CN101478154A - Measure for solving AC, DC earthing and short circuit and novel design of DC system - Google Patents

Abstract

Aiming to solve the problems that the electric power plant trips due to the ground fault for the strings under alternating current or direct current condition, and a plurality of accidents appear, for example, the device is damaged, the important relay coil with easy incorrect-tripping is connected with a shunt resistor in parallel, the communication is carried out between the electric devices, and a rectification, insulating and tripping functional switch is installed on a direct-current power supply branch circuit, so that the influence on the fault source is reduced or isolated. The invention provides a novel direct current system design principle and a method, a special hall sensor for the unbalanced current is adopted, a grounding resistance-capacitance loop is increased, the unbalanced current of the grounding branch circuit is increased, the sensitivity of measurement is improved, a distributed on-site monitoring module finishes the data acquisition and the data transmission of the busbar voltage, the unbalanced current, the on/off state, and the like, the monitoring center finishes processing all the data and warning according to the logic of the design, the tripping command is transmitted to the fault branch circuit through the distributed on-site monitoring module, and a switch with tripping function is used for shutting the fault branch circuit off in time after receiving the command. Therefore, the technical problem that the fault range is extended due to the short circuit and the ground fault for strings under the alternating current and the direct current condition is solved.

Description

Solve the measure and the direct current system new design of string interchange, DC earthing and short circuit

(1) technical field under:

The technical barrier that the present invention is directed to direct current system power failure influences such as solving string interchange, DC earthing and direct-current short circuit or cause other power supply direct current main equipment accidents to enlarge, new solution and method are proposed, and new technology, thinking, principle and the method for direct current system design proposed with this new solution and method, upgraded the direct current system design concept, solve the technical barrier that present direct current system exists, be applicable to the field of any direct current system and dc operation power supply system.

(2) background technology:

At present, in large enterprise or electric power system, the direct current system operating power all is conventional design: comprise batteries, rectifier charging device, distribution loop and monitoring and insulating monitoring device etc., dc bus directly arrives the operating power of main equipment through switch (or fuse), the problem that exists is: the DC power system fault (exchanges as string, DC earthing, direct-current short circuit etc.) can pass through the safe operation that dc bus directly have influence on other direct current operative power sources and main equipment, cause the main equipment malfunction or the tripping of other operational power source circuits that accident is enlarged, insulating monitoring and line selection apparatus that present direct current system is generally used are ac-current inject method, can't correctly judge improved direct current system commutating circuit earth fault, part utilizes the insulating monitoring of Hall sensor and line selection apparatus that the direct current sampling precision is required than higher, be not easy to realize that polling period is long.

A large amount of in recent years microelectronics and new technology are used, the equipment operation reliability requirement is also than higher, particularly the reliability requirement of direct current system operating power is also more and more higher, because the direct current operative power source fault causes big accident and loss often, particularly string exchanges, DC earthing, problems such as direct-current short circuit cause power plant's power cut of whole factory, jump unit and cause accident such as device damage many, I am through theory analysis and test under this background, exchange at string, DC earthing, problems such as direct-current short circuit are carried out case study and investigation, new solution and measure have been proposed, and the design new technology of Novel DC system and corresponding accessory kit thereof proposed with this new solution and measure, thinking, principle and method have solved the technical barrier of present existence.

(3) summary of the invention:

The DC power system fault (exchanges as string, DC earthing, short circuit etc.) time, the source of trouble directly has influence on other direct current operative power sources and main equipment safe operation through dc bus, cause the main equipment malfunction or the tripping of other operational power source circuits that accident is enlarged, at this problem, take at the important relay coil of easily malfunction shunt resistance in parallel, communication contact between important electric equipment, at DC power supply branch road dress commutating circuit, the measures such as direct current special switch of DC/DC direct current equipment for converting and insulating and tripping operation (disconnection) function weaken or have isolated the influence of the source of trouble.At this new approaches of direct current system design are proposed, principle and method: the direct current special switch that adopts the special-purpose Hall sensor of high accuracy unsymmetrical current and band tripping operation (disconnection) function, increase the unsymmetrical current that ground connection capacitance-resistance loop increases the ground connection branch road, improve and measure sensitivity, distributed monitoring module is on the spot finished busbar voltage, unsymmetrical current, the collection of data such as on off state and transmission, Surveillance center finishes all data processing and warning by the logic of design, and by distributed monitoring module on the spot, send out the TRIP instruction to fault branch, the electronic switch of band switch of trip avoidance function or turn-off function is received after the order open failure branch road in time, dwindled the scope of DC power supply fault effects, solved because of direct-current short circuit, string AC and DC earth fault causes the technical barrier of accident expansions such as main equipment malfunction.

The present invention solves string subject matter such as interchange, DC earthing and direct-current short circuit and the solution and method and direct current system design technical scheme (accompanying drawing 1: the be Novel DC system design circuit theory schematic diagram of the present invention) particular content that new technology, principle, thinking and method adopted that propose:

1, interchange of branch road string or DC earthing have influence on the safe operation of other direct current operative power source loop main equipments, cause the principle analysis of switch or protection malfunction.As Fig. 2: DC power supply branch road of supposing 11 and branch road 12 be normally operation all, 11 control contact CKJ11 far away are illogical for branch road, relay coil ZJ11 in the branch road 11 is failure to actuate, certain is the negative electricity subject string AC power E12 fault of branch road 12 constantly, this AC power E12 must be through the switch QFK12 and the dc bus-KM11 of branch road 12, branch road 11 switch QFK11 are to the end (negative power end) of relay coil ZJ11, the other end of coil ZJ11 (positive power source terminal) is connected with ground through the distributed capacitance C11 of cable, constitute the closed loop of AC power E11, if the current ratio that interchange trouble power E12 produces on distributed capacitance C11 is big (as 0.1A), the alternating current (as 0.1A) that promptly flows through relay coil ZJ11 will cause the misoperation (contact CKJ11 is logical, and relay coil ZJ11 should not move and malfunction) of relay coil ZJ11 during greater than the operating current (as 0.05A) of relay coil ZJ11.If (voltage of E12 is zero to the constantly unexpected ground connection of the negative supply E12 of branch road 12, resistance is zero), the electric energy that accumulates on the electric capacity also constitutes closed loop through above-mentioned same path, and the words that the capacitance discharges electric current is enough big also cause the misoperation of relay coil ZJ11 easily.As Togtoh power plant " 10.25 " accident etc. is exactly the case that above-mentioned reason and principle cause the accident and enlarge.For the DC power supply branch, short-circuit, if the not tripping or the dc switch master switch tripping of bypassing the immediate leadership of branch road dc switch may cause the main equipment tripping and accident is enlarged.The method and the measure that solve:

The method one that solves, safeguard procedures to relay: at the two ends of the important exit relay coil that is easy to malfunction shunt resistance in parallel, as Fig. 3, in the two ends of relay coil ZJ11 resistance R 11 that resistance is suitable in parallel, the AC impedance of relay coil ZJ11 is bigger, when above-mentioned string AC power E12 (or ground connection) fault takes place when, electric current I c11 on the distributed capacitance C11 (as 0.1A), shunting (Ir11=0.09A) through resistance 11, the electric current (0.01A) that flows through relay coil ZJ11 is got final product less than operating value (0.05A), relay ZJ11 can misoperation, has weakened the influence of the source of trouble.

The method two that solves; cable capacitance is revealed; the safeguard procedures that cable grounding etc. are taked: at the state that needs the electrical cable contact; distributed monitoring module is on the spot installed in design additional on the equipment of signal and control contact; utilize communication to transmit all data between the equipment; switching value and trip signal etc.; visual plant design duplicate supply; the bimodulus piece; duplex; improve reliability; as sending out protection of change group and ECS; generator outlet switch (establishing distributed monitoring module on the spot); line switching (establishing distributed monitoring module on the spot); main transformer body (establishing distributed monitoring module on the spot); electric data between the equipment such as route protection (analog quantity; switching value; trip signal etc.) all transmit by communication; has only the contact of feed cable and communication cable or optical cable between each main equipment; the amount of laying and the Method of Cable Trouble Point of cable have been reduced; improved antijamming capability, isolated or weakened of the direct influence of DC power supply fault other Main Equipment Protection and control loop.

The method three that solves, the safeguard procedures that DC power system is taked: (1), all branch roads and subordinate's branch road DC power supply switch outlet thereof on dc bus, install commutating circuit (rectifier diode) additional as quarantine measures, when string interchange or earth fault take place when, utilize the principle of the unidirectional energising of rectifier diode, isolation has also weakened the influence of string AC power to other dc power supply circuits, as Fig. 4, if positive and negative dc bus over the ground normal voltage be+55V and-55V, respectively go here and there two isolating diodes (capacity is suitable) D111 at the switch QFK11 of DC power supply branch road 11 and branch road 12 and QFK12 end opening, D112, D121, D122, when above-mentioned string AC power E12 (as 220VAC) fault takes place when, AC power E12 is through diode D122, when the voltage (a point) of E12 greater than DC bus-bar voltage-KM11 (b point,-55V) time effectively (among Fig. 5-55V straight line with top), when the voltage (a point) of E12 less than DC bus-bar voltage-KM11 (b point,-55V) time (among Fig. 5-55V straight line lower part, be the negative peak part of dotted line) since the unidirectional of diode D122 be cut off, on dc bus-KM11, have only among Fig. 5-waveform on 55V straight line top, the negative peak part that is dotted line has been reamed, power supply on dc bus-KM11 passes through the same effect of diode D112 again, the load end of diode D112 (d point) is the highest voltage to earth+55V normally, promptly when the voltage (c point) of the bus end of diode D112 during less than load end (d point) voltage of diode D112 (among Fig. 5+55V straight line top, be the positive peak part of dotted line) also because the unidirectional of diode D112 is cut off, string interchange earthing power supply E12 can only show as the DC power supply in the scope in branch road 11.And because the unidirectional of diode D112, D122, string exchanges the E12 trouble power and do not produce AC signal on the distributed capacitance C11 of cable, do not constitute the closed loop of AC power E11, branch road 12 string exchange the E12 faults to branch road 11 relay coil ZJ11 without any influence.When above-mentioned E12 earth fault (E12 is 0) takes place, the electric energy of distributed capacitance C11 since the buffer action of diode D122 and D112 can not discharge over the ground through branch road 11 relay coil ZJ11 and earth point E12, to relay coil ZJ11 also without any influence.Equally isolate diode D121 when fault such as string AC and DC ground connection takes place and D111 also can play above-mentioned same effect in that branch road 12 is anodal, solved the safe operation that faults such as string AC and DC ground connection do not influence other duplexures.(2), all branch roads and subordinate's branch road DC power supply switch outlet thereof on dc bus, design the equipment for converting and insulating of new DC/DC direct current special use, DC/DC electric energy transducer DC/DC21 as Fig. 1 branch road 21, i.e. input, output is equal direct current energy transducer, has the electrical isolation effect, load end generation string interchange when branch road 21, ground connection, during DC power supply faults such as short circuit, because the buffer action of direct current transducer, only work to the load of branch road 12 in the fault point, isolated influence, and signals such as internal fault have been transferred to distributed monitoring module on the spot (as the MK2 of Fig. 1) other dc power supply circuits.

The method four that solves; the safeguard procedures that the branch road mains switch is taked: (1); design new direct current special switch (as the QFK11 of Fig. 1; QFK12 etc.); this direct current power source special switch designs has on off state contact (switch closes state); functions (outer protection contact TRIP function) such as action connection point (improper tripping operation such as overcurrent) and the outside trip signal TRIP of acceptance; receiving outside tripping operation make (as the outlet of the distributed MK1 of monitoring module on the spot of Fig. 1 contact that trips) to have the function of TRIP (as the QFK11 of Fig. 1; switches such as QFK12); calculate and the timely tripping trouble power of logic analysis branch road according to sampled data; branch road 11 faults as Fig. 1; Surveillance center disconnects the QFK11 switch by the outlet tripping operation contact of the distributed MK1 of monitoring module on the spot, has isolated the influence of branch road 11 fault points to other direct current systems.(2), the electronic switch (as the GFK11 of Fig. 1) of design direct current special use, be divided into and accept to have source contact to turn-off electronic switch, wireless remote control turn-offs electronic switch and serial communication turn-offs three kinds of electronic switches, with the new direct current special switch of above-mentioned design (as the QFK11 of Fig. 1) effect, receive and outside close order (as the outlet tripping operation contact of the distributed MK0 of monitoring module on the spot of Fig. 1 or by wireless, the open command of serial communication etc. transmission) turn-offs the function of the electronic switch (as the GFK11 of Fig. 1) of corresponding function, and have status signal and be transferred to distributed monitoring module on the spot (as the MK0 of Fig. 1).Isolated of the influence of branch road 1 fault point, the scope of having dwindled the DC power supply fault effects to other direct current systems.

The method five that solves, to the improved measure of dc system grounding route selection: as Fig. 1, owing in above-mentioned solution three, proposed to increase in the DC power supply branch road rectifier diode (D11 in as Fig. 1, D12, D111, D112 etc.) or DC/DC direct current energy transducer (as DC/DC21 among Fig. 1) as quarantine measures, traditional dc system grounding line selection apparatus can not meet the demands, dc system grounding route selection design adopts new high accuracy direct current unsymmetrical current (as Hall sensor H1 among Fig. 1, H11, H12 etc.) judge ground connection and select correct branch road, it is the power supply wiring of one group of two different capabilities that the special-purpose Hall sensor of direct current unsymmetrical current is designed to go here and there primary winding unshakable in one's determination, and primary winding twines multi-turn (be equivalent to measure a direct current leakage electric current many times) as requested, has improved certainty of measurement and sensitivity.Design increases ground connection capacitance-resistance loop (as resistance R 0 and the capacitor C 0 of Fig. 1), data analysis and logic determines through direct current system supervisory control system (Surveillance center and the distributed MK0 of monitoring module on the spot), (minus earth is K1 by the distributed MK0 of monitoring module on the spot control relay by Surveillance center, plus earth is K2) action, select bus to drop into ground connection capacitance-resistance loop, unsymmetrical current when increasing the ground connection branch trouble, improve and measure sensitivity, and in ground connection capacitance-resistance loop, increase Hall sensor (as the Hall sensor H0 of Fig. 1) and measure the ground connection Leakage Current and be used for auxiliary judgment, accurately judge ground path and earth point rapidly, the electric capacity (as the capacitor C 0 of Fig. 1) of capacitance-resistance loop serial connection, avoid the direct ground connection of (relay (K1 or K2) that is to say ground connection capacitance-resistance loop was thrown in the time of moving back) dc bus in ground connection detection and route selection process, reduced the failure rate of dc bus.

2, exchange at string, influence of dc system fault such as DC earthing and direct-current short circuit or the problem that causes other DC loop main equipment accidents to enlarge, above-mentioned solution one, the two design new technologies that can only take at main equipment, method and measure, in the direct current system design, by above-mentioned solution three, four, the measure of describing in detail in five proposes to install quarantine measures such as rectifier diode or DC/DC direct current energy transducer additional in each direct current branch design, earthing wire-selecting is judged in the Hall sensor of design high-acruracy survey direct current unsymmetrical current and increase ground connection capacitance-resistance loop, the scope that design band trip avoidance function direct current special switch or turn-off function direct current special electronic switch dwindle the DC power supply fault effects, design the design new technology of Novel DC systems such as distributed monitoring module on the spot and direct current centralized monitoring system (Surveillance center) monitoring in real time, thinking, principle and method.

In the Novel DC system design of above-mentioned proposition, increase design DC distribution split screen at the dc load center, the direct current special switch of each branch road band tripping operation (or shutoff) function in the design split screen, rectifier diode or DC/DC direct current energy transducer, the special-purpose Hall sensor of direct current unsymmetrical current, design increases ground connection capacitance-resistance loop on dc bus, in above-mentioned solution three, four, described in detail in five, the distributed monitoring module on the spot of design specialized is to each DC distribution branch road in the split screen and bus parameter centralized monitor, have real-time monitoring and gather analog data and (measure busbar voltage on the spot in real time, the branch road unsymmetrical current, bus insulation resistance etc.), switching value input (branch switch state, emergency stop valve trip signal or fuse melting signal), control command output (switching value output, can jump branch switch according to a condition distant place) and function such as communication, receive Surveillance center start patrol and examine instruction after, each distributed in-site collecting monitoring module is finished busbar voltage synchronously, data acquisition and maximums such as each branch switch state of each branch road unsymmetrical current, primary Calculation such as weighted average, in time transfer of data is arrived Surveillance center, after receiving Surveillance center's jumping fault branch order, in time selectivity is jumped the fault branch switch or is turn-offed corresponding electronic switch.

In the Novel DC system design of above-mentioned proposition, direct current centralized monitoring system (Surveillance center) (is finished all data processing and warning as Figure 10-Figure 14) by the logic diagram of design, and pass through distributed monitoring module on the spot (as MK0 among Fig. 1, MK1, MK2), send out the TRIP order to fault branch (branch road 11 in as Fig. 1), direct current special switch (as QFK11 among Fig. 1 etc.) or direct current special electronic switch (as GFK1 among Fig. 1) are received outside tripping operation makes tripping fault point branch switch (above-mentioned solution four) immediately, begin to selecting correct branch road and tripping fault point branch switch from fault, only need little time (as a few tens of milliseconds), reduced polling period, improved reaction speed, can in time take measures (jumping the branch road mains switch), reduce because of string AC and DC ground connection, the probability that direct current faults such as short circuit cause other main equipment accidents to enlarge.

Direct current centralized monitoring system (Surveillance center), by with the distributed communication of monitoring module and rectification module etc. on the spot, real-time sampling and analytical test direct-current power supply ripple coefficient, direct current system voltage is monitored in real time, battery pack and charging and discharging of accumulator electric current automatic or manual are measured, the charge-discharge characteristic of analytical test direct-flow storage battery and batteries, the quality of judgement direct-flow storage battery.Integrate D.C. isolation supervision and route selection, discharge and recharge rectification module monitoring, the direct current centralized monitoring system of the major function of accumulator cell charging and discharging characteristic test and devices such as curve is recorded, the attributional analysis of dc bus power supply.Reduce the investment of direct current system equipment, also reduced the fault point, improved the operational reliability of direct current system.

Direct current centralized monitoring system (Surveillance center) adopts industrial computer and Chinese Windows operating system, be easy to be familiar with, the programming of operation, system and software upgrading etc., the capacity of memory is big, can store more fault and recorder data, be provided with power down and preserve data function, when preserving fault or each measuring point data (recorder data that comprises a period of time before and after starting) when manually booting the record ripple, realize the high-resolution logout, can draw at this machine, utilize zoom function, can observe the trickleest details.Possess parameter setting, equipment self-inspection, accident record, warning, printing and with the functions such as Ethernet, UBS, serial and speech interface of other system communication.Details are as follows with regard to the logic function of its earthing wire-selecting in Surveillance center:

(1), during to branch road ground connection (or string exchanges) fault, R11 ground connection or E11 string as Fig. 6 branch road 11 exchange fault, mainly contain dc bus voltage to earth imbalance (as Fig. 6 dc bus ± KM1 and ± busbar voltage of KM11) and ground connection branch road direct current imbalance (as the H1 of Fig. 6, phenomenon such as H11), start and return decision logic figure as Figure 10, judge by positive and negative busbar voltage to earth degrees of offset (bus is over against the negative voltage to earth value of ground voltage value-bus=busbar voltage deviant): metallic earthing (deviant/rated value is greater than setting value), nonmetal character ground connection (deviant/rated value is in suitable scope), plus earth (deviant is that negative value is less than zero), minus earth (deviant be on the occasion of greater than zero), bus insulation does not normally have ground connection (deviant/rated value is less than setting value), voltage to earth comprehensive for the crest voltage that exchanges and busbar voltage when string exchanges is when crest voltage is judged to the string interchange during greater than dc rated voltage (as 1.2 times).

Start and return the criterion logic diagram as Figure 10, gather and calculate busbar voltage in real time, positive and negative insulation against ground resistance value and insulating resistance value rate of change etc., and according to bus voltage to earth rate of change, arbitrary value all starts the earthing wire-selecting program greater than the startup value of correspondence in the rate of change of busbar voltage skew and three conditions of insulating resistance value rate of change, start each data acquisition of distributed monitoring module on the spot and calculating simultaneously, and drop into relay K 2 (or K1) respectively ground connection capacitance-resistance loop is devoted negative (or just) bus according to just (or negative) polarity of earth bus, increase ground connection branch road Leakage Current.Start the back or recover the normal value certain hour of delaying time again when busbar voltage and bus insulation, withdraw from the relay K 2 (or K1) in ground connection capacitance-resistance loop, and the discharge resistance over the ground (as resistance R among Fig. 1 01) in connection ground connection capacitance-resistance loop, discharge the energy of electric capacity (as capacitor C among Fig. 1 0), the no electric charge of electric capacity (as capacitor C among Fig. 1 0) when dropping in order to next time, ground connection unsymmetrical current sampling period and sampling precision that capacitance-resistance resistance in circuit value (as resistance R among Fig. 10 and R01) and capacitance (as capacitor C among Fig. 1 0) are selected to satisfy each branch road and capacitance-resistance loop get final product.

In relay K 1 (or K2) action during this period of time in (being that the time of moving back is thrown in ground connection capacitance-resistance loop), start the ground connection Leakage Current (as the H0 of Fig. 6) of gathering all branch road ground connection unsymmetrical currents (as the H1 of Fig. 6 and H11 etc.) and ground connection capacitance-resistance loop simultaneously by distributed monitoring module on the spot, the maximum of analytical calculation image data and weighted average (following said earth current, unsymmetrical current or ground connection Leakage Current etc. are two groups of corresponding maximum and weighted averages respectively), and data in time are transferred to Surveillance center's analyzing and processing.

(2) when DC earthing (or string exchanges) takes place, start according to above-mentioned Figure 10 and return the criterion logic diagram and judge and confirm earth fault type by the Surveillance center of direct current system, start the earthing wire-selecting process, R11 minus earth as Fig. 6, drop into K1 positive bus-bar ground connection capacitance-resistance loop, exchange or the earthing discrimination logic diagram as Figure 12 branch road string, the ground connection unsymmetrical current that ground connection branch road Hall sensor detects (as the H1 of Fig. 6 and H11 etc.) is greater than set point, the ground connection unsymmetrical current that earth-free other branch road Hall sensors detect (as the H12 of Fig. 1 etc.) less than set point, the ground connection Leakage Current (as the H0 of Fig. 6) that detects of the Hall sensor in the ground connection capacitance-resistance loop of Tou Ruing is greater than set point simultaneously, selects correct ground connection branch road number.

DC earthing exchanges the differentiation of fault with the direct current string: when interchange seals in direct current, exchange fault as the anodal string of the E11 of Fig. 6, the busbar voltage of sampling over the ground (as Fig. 6 dc bus ± KM1 and ± busbar voltage of KM11) be main criterion greater than dc rated voltage (as more than 1.2 times).In addition, drop into K2 negative busbar ground connection capacitance-resistance loop, the detected ground connection unsymmetrical current of the Hall sensor of ground connection branch road (as the H1 of Fig. 6 and H11 etc.) is direct current leakage electric current and the always over the ground Leakage Current of AC power by other all branch roads of itself, therefore the detected ground connection unsymmetrical current of Hall sensor of ground connection branch road (as the H1 of Fig. 6 and H11 etc.) will be zero metallic earthing unsymmetrical current (set point) greater than earth resistance, the detected ground connection Leakage Current of Hall sensor (as the H0 of Fig. 6) in the ground connection capacitance-resistance loop that installs additional is also greater than set point, as the assistant criteria of string interchange.

When dc bus ± KM has ground connection or string to exchange, start the earthing wire-selecting process, R0 or E1 bus negative pole fault as Fig. 7, drop into K1 positive bus-bar ground connection capacitance-resistance loop, exchange the differentiation logic diagram with string as Figure 11 busbar grounding, all branch road ground connection unsymmetrical currents (as the H1 of Fig. 7) are all less than the startup value, but the busbar voltage imbalance satisfies condition (deviant/rated value is greater than setting value), the ground connection Leakage Current (as the H0 of Fig. 7) of the Hall sensor in the ground connection capacitance-resistance loop of Tou Ruing detection simultaneously is also greater than set point, be the busbar grounding fault, the bus voltage to earth exchanges main criterion greater than dc rated voltage (as more than 1.2 times) for string in addition, the assistant criteria that the detected ground connection Leakage Current of Hall sensor (as the H0 of Fig. 6) in the ground connection capacitance-resistance loop that installs additional also exchanges as string greater than set point.

Select different branch road number and earth point according to above-mentioned same principle when 2 above ground connection or string exchange, and analyze the earth fault type of each earth point, (comprise warnings, jump branch road, record ripple and preservation data and figure etc.) takes appropriate measures.

Above criterion is all judged earth point and earth fault type by maximum and weighted average respectively.As Figure 10 to Figure 12 logic diagram, by maximum, weighted average and over the ground condition such as sampled voltage satisfy the logic OR relation of setting and report to the police, after satisfying the logical AND relation of setting, again according to open barring conditions such as on off state, device setting, equipment operation situation and plant failure warnings, send out jumping fault branch switch command (or turn-offing fault branch electronic switch) and warning and also in time enroll the Wave data of accident point, form database file and graphic file.

(3), for the judgement and the processing that have loop in the direct current system branch road, as Fig. 9, branch road 1 switch QFK1, branch road 2 switch QFK2 and ± when the bar coupler MK12 of KM11 and ± KM21 closes a floodgate, branch road bus ± KM11 and ± KM21 loop operation.Logic diagram is differentiated in operation as Figure 13 branch road bus loop, judges that according to the branch switch (as QFK1, the QFK2 of Fig. 9) of 2 buses and the "on" position contact of interconnection switch (as the MK12 of Fig. 9) 2 sections separate branches buses move through the interconnection switch loop.In addition, do not having under the situation of DC earthing, 2 sections independent direct current buses are through the operation of interconnection switch loop, and the electric characteristic before and after the loop operation changes: 2 groups of buses and 2 groups of branch road buses (as Fig. 9 ± KM11 and ± KM21) over the ground insulation resistance balance, no bus and branch road ground connection situation; 2 groups of branch road busbar voltages, voltage to earth and insulation against ground are by original unequal identical suddenly; For the unsymmetrical current (as H1 and the H2 of Fig. 9) all unexpected big (greater than set point) that the Hall sensor of 2 sections independent direct current bus inlet wire branch roads is monitored, each branch road of its subordinate does not all have unsymmetrical current (as H11, the H21 etc. of Fig. 1) (less than set point); The unsymmetrical current direction that the Hall sensor of the inlet wire branch road of loop bus detects opposite (as H1 and the H2 current opposite in direction of Fig. 9); Come 2 sections separate branches buses of auxiliary judgment to move by maximum and weighted average respectively according to above-mentioned 4 conditions through the interconnection switch loop.And according to situation about judging, take appropriate measures (comprise warning, jump interconnection switch, record ripple and preserve data and figure etc.).

(4), for the judgement and the processing of short circuit in the direct current system branch road, as Fig. 9, the outlet of branch road 11 d11 that is short-circuited, differentiate logic diagram as Figure 13 branch, short-circuit, according to branch current (as Fig. 9, the H1 of the electric current H11 of branch road 11 and total branch road 1) greater than set point and current changing rate (as Fig. 9, the H1 of the electric current H11 of branch road 11 and total branch road 1) greater than set point, judge by branch, short-circuit and overload differentiation logic diagram as Figure 13: overload, closing pulse electric current and short circuit current, judge the branch, short-circuit fault by maximum and weighted average respectively.By maximum, the weighted average design conditions satisfy the logic OR relation of setting and report to the police, after satisfying the logical AND relation of setting, again according on off state, device is provided with, open barring condition such as equipment operation situation and plant failure warning, send out and jump fault branch switch command (or on-off switching tube) and warning, the certain hour of delaying time, not tripping of short circuit branch switch (as the QFK11 tripping of Fig. 9 branch road 11), and this moment branch current (as Fig. 9, the H1 of the electric current H11 of branch road 11 and total branch road 1) still greater than the short circuit set point, according to the situation that is provided with of branch road master switch (as the QFK11 of Fig. 9 branch road 1 or as the GFK1 of Fig. 1 branch road 1 etc.), jump branch road master switch (as the QFK11 of Fig. 9 branch road 1 or as the GFK1 of Fig. 1 branch road 1 etc.).And in time enroll the Wave data of accident point, form database file and graphic file.

(5), the parameters of real-time sampling DC bus-bar voltage, the analytical test direct-current power supply ripple coefficient is to real-time ripple voltage test of direct current system voltage and monitoring.

(6), the charging and discharging currents automatic or manual of battery pack is measured, the charge-discharge characteristic of analytical test direct-flow storage battery group is to the battery pack test and the monitoring of direct current system.Also can expand to each charging and discharging of accumulator electric current automatic or manual is measured, the charge-discharge characteristic of all direct-flow storage batteries of analytical test, judge the quality of direct-flow storage battery, take appropriate measures (comprise warning, replenish discharge, record ripple and preserve data and figure etc.).

The beneficial effect of patent of the present invention is: exchange at string, direct current such as DC earthing and direct-current short circuit fault directly has influence on the technical barrier of the main equipment safe operation of other dc power supply circuits through dc bus, novel solution and measure are proposed, and the mentality of designing of direct current system novelty proposed, principle and method, improved the new concept of direct current system design, solved the ubiquitous technical barrier of present direct current system, can be applied in all direct current system designs, to reduce the probability that dc system fault causes main equipment substantial equipment accident and economic loss, obvious social benefit greatly after the enforcement.

(4) description of drawings

Below in conjunction with drawings and Examples Novel DC system design principle of the present invention, thinking and method are further specified.

Fig. 1: Novel DC system design circuit theory schematic diagram of the present invention.

Fig. 2: the direct current system string exchanges the circuit theory diagrams of (or ground connection) relay misoperation at present.

Fig. 3: parallel resistance solves the circuit theory diagrams of direct current system string AC relay malfunction.

Fig. 4: commutating circuit (diode) solves the direct current system string as quarantine measures and exchanges.

Fig. 5: voltage to earth oscillogram on the bus that commutating circuit (diode) is isolated.

Fig. 6: the branch road string exchanges or the earthed circuit schematic diagram.

Fig. 7: the bus string exchanges or the earthed circuit schematic diagram.

Fig. 8: bus loop circuit schematic diagram.

Fig. 9: branch, short-circuit circuit theory diagrams.

Figure 10: start and return the criterion logic diagram.Among Fig. 9,1: the busbar voltage degrees of offset is greater than set point; 2: the rate of change of bus offset voltage is greater than set point; 3: bus insulation resistance change rate is greater than set point; 4: plus or minus bus voltage to earth amplitude of variation is greater than set point; 5: start insulation route selection process and the distributed sampling of monitoring on the spot instruction; 6: the bus insulation resistance value is greater than set point; 7: the bus voltage to earth recovers normal; 8: the beginning analyzing and processing data; 9: bus insulation is normal; 10: busbar voltage does not have skew (deviant/rated value is following less than 10% (can adjust)); 11: nonmetal character ground connection (about deviant/rated value 95%-10% (can adjust)); 12: nonmetal character ground connection; 13: metallic earthing (deviant/rated value is greater than more than 95% (can adjust)); 14: metallic earthing; 15: minus earth (deviant be on the occasion of greater than zero); 16: start minus earth (K1 is moving); 17: plus earth (deviant is that negative value is less than zero); 18: start plus earth (K2 is moving).

Figure 11: busbar grounding exchanges with string differentiates logic diagram.Among Figure 11,1:(bus voltage to earth/rated voltage) maximum is greater than set point; 2: all branch road ground connection unsymmetrical current maximums are all less than set point; The Leakage Current of the ground connection Leakage Current/metal ground connection in 3:(capacitance-resistance loop) maximum is greater than set point; The Leakage Current of the ground connection Leakage Current/metal ground connection in 4:(capacitance-resistance loop) weighted average is greater than set point; 5: bus negative pole string exchanges fault; 6: the anodal string of bus exchanges fault; 7: all branch road ground connection unsymmetrical current maximums are all less than set point; 8: the ground connection Leakage Current maximum in ground connection capacitance-resistance loop is greater than set point; 9: the busbar grounding signal; 10: bus minus earth signal; 11: bus plus earth signal; 12: all branch road ground connection unsymmetrical current weighted averages are all less than set point; 13: the ground connection Leakage Current weighted average in ground connection capacitance-resistance loop is greater than set point; 14: busbar grounding is reported to the police; 15: bus minus earth fault; 16: bus plus earth fault; 17: start minus earth (K1 is moving); 18: start plus earth (K2 is moving).

Figure 12: the branch road string exchanges or the earthing discrimination logic diagram.Among Figure 12,1:(bus voltage to earth/rated voltage) weighted average is greater than set point; 2:(bus voltage to earth/rated voltage) maximum is greater than set point; 3: branch road negative pole string AC signal; The ground connection Leakage Current in 4:(branch road ground connection unsymmetrical current/ground connection capacitance-resistance loop) maximum is greater than set point; The Leakage Current of 5:(branch road ground connection unsymmetrical current/metal ground connection) maximum is greater than set point; 6: branch road string AC signal; 7: the anodal string of branch road AC signal; The ground connection Leakage Current in 8:(branch road ground connection unsymmetrical current/capacitance-resistance loop) weighted average is greater than set point; The Leakage Current of 9:(branch road ground connection unsymmetrical current/metal ground connection) weighted average is greater than set point; 10: the branch road string exchanges reports to the police; 11: branch road negative pole string exchanges reports to the police; 12: the anodal string of branch road exchanges reports to the police; 13: branch road ground connection unsymmetrical current maximum is greater than set point; 14: the ground connection Leakage Current maximum in ground connection capacitance-resistance loop is greater than set point; 15: the branch road ground signalling; 16: branch road minus earth signal; 17: branch road ground connection unsymmetrical current weighted average is greater than set point; 18: the ground connection Leakage Current weighted average in ground connection capacitance-resistance loop is greater than set point; 19: the branch road grounding alarm; 20: branch road plus earth signal; 21: branch road dc switch state closes; 22: start minus earth (K1 is moving); 23: start plus earth (K2 is moving); 24: the branch road minus earth is reported to the police; 25: the branch road minus earth is reported to the police; 26: equipment running status; 27: branch switch is provided with to throw and jumps; 28: the self-check of device fault-free.

Figure 13: logic diagram is differentiated in the operation of branch road bus loop.Among Figure 13,1: bus 1 branch road dc switch state closes; 2: bus 2 branch road dc switch states close; 3: the contact dc switch state of bus 1 and bus 2 closes; 4: the operation of bus contact loop is reported to the police; 5: branch road ground connection unsymmetrical current maximum is all less than set point; 6: the ground connection Leakage Current maximum in ground connection capacitance-resistance loop is less than set point; 7: bus 1 branch road unsymmetrical current maximum is greater than set point; 8: bus 2 branch road unsymmetrical current maximums are greater than set point; 9: branch road ground connection unsymmetrical current weighted average is all less than set point; 10: the ground connection Leakage Current weighted average in ground connection capacitance-resistance loop is less than set point; 11: bus 1 branch road unsymmetrical current weighted average is greater than set point; 12: bus 2 branch road unsymmetrical current weighted averages are greater than set point; 13: bus 1 branch road unsymmetrical current and bus 2 branch road unsymmetrical current directions are anti-; 14:(bus 1 insulation against ground resistance-bus 2 insulation against ground resistance buses) less than set point; 15: the contact dc switch is provided with to throw and jumps; 16: the self-check of device fault-free.

Figure 14: logic diagram is differentiated in the branch, short-circuit overload.Among Figure 14,1: the branch current maximum is greater than the short circuit set point; 2: the branch current rate of change is greater than set point; 3: branch road dc switch state closes; 4: the branch, short-circuit tripping alarm; 5: the branch current weighted average is greater than the short circuit set point; 6: branch current rate of change weighted average is greater than set point; 7: the branch, short-circuit signal alarm; 8: branch switch is provided with to throw and jumps; 9: branching unit self check fault-free; 10: the branch, short-circuit trip command; 11: the instruction of branch road master switch is jumped in branch, short-circuit tripping time-delay; 12: branch road master switch state closes; 13: the branch road master switch is provided with to throw and jumps; 14: branch road master switch self-check of device fault-free; 15: the locking of branch road master switch is open; 16: the branch current maximum is greater than the overload set point; 17: branch current rate of change maximum is less than set point; 18: branch road overload signal alarm; 19: the branch current weighted average is greater than the overload set point; 20: branch current rate of change weighted average is less than set point; 21: branch road overload tripping alarm; 22: branch road overload trip command; 23: the branch current maximum is less than set point; 24: branch current rate of change maximum is greater than set point; 25: the branch current weighted average is less than set point; 26: branch current rate of change weighted average is greater than set point; 27: branch road closing pulse signal alarm.

(5) embodiment

At Fig. 1: in the embodiments of the invention; at solving because of the string interchange; the technical barrier that DC earthing and direct-current short circuit fault cause accidents such as main equipment malfunction or tripping to enlarge; adopted the direct current special switch (QFK11 etc.) of band trip avoidance function respectively; the electronic DC switch (GFK1) of band turn-off function; isolate the rectifier diode (D111 that weakens AC power; D112 etc.); the DC/DC electric energy transducer (DC/DC21) of DC-isolation; Hall sensor (the H11 of high-acruracy survey direct current unsymmetrical current; H21 etc.); the ground connection capacitance-resistance loop (K1 that increases for the unsymmetrical current that increases the ground connection branch road; K2; R0; C0; R01); distributed decentralized supervisory control of monitoring module on the spot and measures such as Surveillance center's centralized Analysis and processing; busbar grounding when capacitor C 0 is avoided detecting, the current-limiting protection resistance when R01 is the C0 discharge.

The design principle of direct current system novelty is proposed at above measure, thinking and method, design Surveillance center's 1 cover as Fig. 1, logic by design is finished all data processing and warning, and by communication and the distributed MK0 of monitoring module on the spot, MK1, the MK2 contact, be provided with man-machine interfaces such as display and keyboard, dc bus ± KM1, ± KM2 is a main bus bar, the busbar voltage of the distributed MK0 of monitoring module on the spot monitoring dc bus ± KM1, all branch road unsymmetrical currents (H1 of Fig. 1 branch road 1 etc.) and all branch switchs or electronic switch (Fig. 1 branch road 1 is electronic switch GFK1), also the instruction and the switching value order of Surveillance center are carried out in transmission simultaneously, the distributed MK0 of monitoring module on the spot drives the K1 or the K2 actuating of relay according to the instruction of Surveillance center, be respectively applied for and drop into ground connection capacitance-resistance loop increase ground connection branch road unsymmetrical current when negative pole or plus earth, dc bus ± KM2 also has an above-mentioned same cover system.Branch road dc bus ± the KM11 of branch road 1 also is provided with a distributed MK1 of monitoring module on the spot, busbar voltage, all branch road unsymmetrical currents (H11 of Fig. 1 branch road 1, H12 etc.) and all branch switchs or the electronic switch (as the direct current special switch QFK11 of branch road among Fig. 1 11) of monitoring and control dc bus ± KM11, also the instruction and the switching value order of Surveillance center are carried out in transmission simultaneously, and the distributed MK1 of monitoring module on the spot is according to the instruction difference tripping or the last corresponding branch switch of shutoff ± KM1 of Surveillance center.Branch road dc bus ± the KM21 of branch road 2 also is provided with a distributed MK2 of monitoring module on the spot, the state and the operation monitoring of busbar voltage, all branch road unsymmetrical currents (H21 of Fig. 1 branch road 1 etc.) and all branch road equipment for converting and insulating (as the direct current DC/DC electric energy transducer DC/DC21 of branch road among Fig. 1 21) thereof of monitoring and control dc bus ± KM21, also the instruction and the switching value order of Surveillance center are carried out in transmission simultaneously, and the distributed MK1 of monitoring module on the spot is according to instruction difference tripping or the last corresponding branch switch of shutoff ± KM21 or the spacer assembly of Surveillance center.And in time report to the police and start that fault and data are preserved and the record wave energy, print and preserve database file and waveform graph file etc.

The data of equipment such as the distributed MK0 of monitoring module on the spot, MK1, MK2 and rectifying device are gathered and handle by Surveillance center by communication, realization is monitored in real time to direct current system voltage, the analytical test direct-current power supply ripple coefficient, to battery pack and charging and discharging of accumulator current measurement and analysis charge-discharge characteristic, judge the quality of storage battery.Realization integrates D.C. isolation supervision and route selection, discharges and recharges the direct current centralized monitoring system of the major function of rectification module monitoring, accumulator cell charging and discharging characteristic test and devices such as curve is recorded, the attributional analysis of dc bus power supply, reduce equipment investment, improved the reliability of equipment.

Surveillance center adopts industrial computer and Chinese Windows operating system, be easy to be familiar with, operation and system programming upgrading etc., capacity according to memory, can store more fault and recorder data, be provided with power down and preserve data function, when preserving fault or each measuring point data (recorder data that comprises a period of time before and after starting) when manually booting the record ripple, realize the high-resolution logout, can draw at this machine, utilize zoom function, can observe the trickleest details.Adopt industrial computer be easy to realize parameter setting, equipment self-inspection, accident record, warning, printing and with the functions such as Ethernet, UBS, serial and speech interface of other system communication.

Claims (9)

1, the technical barrier that influences or cause other DC loop main equipment accidents to enlarge at direct current system power failures such as string interchange, DC earthing and direct-current short circuit, new solution and method are proposed, and new technology, thinking, principle and the method for direct current system design proposed with this new measure and method, upgrade the direct current system design concept, solved the technical barrier that present direct current system exists.Be following five new methods of addressing the above problem, measure and propose new technology, thinking, principle and the method for Novel DC system design for the claim of the present invention patent with this, and all products of producing in view of the above.

2, the method one of Xie Jueing, safeguard procedures to relay: at the two ends of the important exit relay coil that is easy to malfunction shunt resistance in parallel, when the generation interchange seals in direct current (or DC earthing) fault, because the AC impedance of relay coil is more much bigger than shunt resistance in parallel, alternating current is most of through the parallel resistor shunting during fault, the electric current that flows through relay coil is got final product less than operating value, make the relay can misoperation, weakened the influence of the source of trouble.

3; the method two that solves; cable capacitance is revealed; the safeguard procedures that cable grounding etc. are taked: at all states that need the electrical cable contact; distributed monitoring module is on the spot installed in design additional on the equipment of signal and control contact; utilize communication data transmission between the equipment; switching value and trip signal etc.; visual plant design duplicate supply; the bimodulus piece; duplex; improve reliability; as sending out protection of change group and ECS; generator outlet switch (establishing distributed monitoring module on the spot); line switching (establishing distributed monitoring module on the spot); main transformer (establishing distributed monitoring module on the spot); electric data between the equipment such as route protection (analog quantity; switching value; trip signal etc.) all transmit by communication; has only the contact of feed cable and communication cable or optical cable between each main equipment; cable laying and fault point have been reduced; improved antijamming capability, isolated or weakened of the direct influence of DC power supply fault other equipment protection and control loop.

4, the method three of Xie Jueing, the safeguard procedures that DC power system is taked: (1), all branch roads and subordinate's branch road DC power supply switch outlet thereof on dc bus, install rectifier diode additional and make quarantine measures, utilize the principle of the unidirectional conducting of rectifier diode, isolate and weakened the influence of string AC power (part that exceeds the direct voltage scope) other dc power supply circuits.(2), all branch roads and subordinate's branch road DC power supply switch outlet thereof on dc bus, (input, output are equal direct voltage electric energy transducer to the isolation and switching device of design DC/DC direct current special use, but has the electrical isolation effect), when the generation interchange seals in the DC power supply fault, because the buffer action of current/direct-current conversion device has been isolated the influence of fault point to other dc power supply circuits.

5, the method four of Xie Jueing; the safeguard procedures that the branch road mains switch is taked: (1), futuramic direct current special switch, this direct current power source special switch designs have on off state contact (switch closes state), action connection point (improper tripping operation such as overcurrent) and accept function (outer protection contact TRIP function) such as outside trip signal TRIP.(2), the novel electronic switch of design direct current special use, can be divided into and accept to have source contact shutoff electronic switch, wireless remote control shutoff electronic switch and serial communication to turn-off three kinds of electronic switches, have the function that (orders such as tripping operation contact, remote control or communication tripping operation) shutoff electronic switch and status signal output are ordered in the outside pass of acceptance.Surveillance center sends the order of jumping fault branch according to failure condition and logic, jumps the fault branch switch or turn-offs corresponding electronic switch through the distributed selectivity of monitoring module on the spot, has dwindled the scope of DC power supply fault effects.

6, the method five that solves, to the improved measure of dc system grounding route selection: owing in above-mentioned solution three, proposed to increase in the DC power supply branch road rectifier diode or DC/DC direct current energy transducer as quarantine measures, traditional dc system grounding line selection apparatus can not meet the demands, design adopts novel high accuracy direct current unsymmetrical current to judge ground connection and select correct branch road, it is the power supply wiring of one group of two different capabilities that the special-purpose Hall sensor of novel high accuracy direct current unsymmetrical current is designed to go here and there primary winding unshakable in one's determination, and primary winding twines multi-turn (be equivalent to measure a direct current leakage electric current many times) as requested, has improved certainty of measurement and sensitivity.Design increases ground connection capacitance-resistance loop, data analysis and logic determines through direct current system supervisory control system (Surveillance center and the distributed MK0 of monitoring module on the spot), move by the distributed MK0 of monitoring module on the spot control relay K1 (or plus earth is K2) by Surveillance center, select bus to drop into ground connection capacitance-resistance loop, unsymmetrical current when increasing the ground connection branch trouble, improve and measure sensitivity, and increase Hall sensor measurement ground connection Leakage Current is used for auxiliary judgment in ground connection capacitance-resistance loop, accurately judge ground path or earth point rapidly, the electric capacity of capacitance-resistance loop serial connection, avoid the direct ground connection of (relay that is to say ground connection capacitance-resistance loop was thrown in the time of moving back) dc bus in ground connection detection and route selection process, reduced the failure rate of DC earthing detection and route selection process median generatrix.

7, exchange at string, influence of dc system fault such as DC earthing and direct-current short circuit or the problem that causes other DC loop main equipment accidents to enlarge, above-mentioned solution one and the two design new technologies that can only take at main equipment, method and measure, in the direct current system design, by above-mentioned solution three, four, the measure of describing in detail in five proposes to install quarantine measures such as rectifier diode or DC/DC direct current energy transducer additional in each direct current branch design, earthing wire-selecting is judged in the Hall sensor of design high-acruracy survey direct current unsymmetrical current and increase ground connection capacitance-resistance loop, the scope that design band trip avoidance function direct current special switch or turn-off function direct current special electronic switch dwindle the DC power supply fault effects, design the design new technology of Novel DC systems such as distributed monitoring module on the spot and direct current centralized monitoring system (Surveillance center) monitoring in real time, thinking, principle and method.

8, in the Novel DC system design of above-mentioned proposition, increase design DC distribution split screen at the dc load center, the direct current special switch of each branch road band tripping operation (or shutoff) function in the design split screen, rectifier diode or DC/DC direct current energy transducer, the special-purpose Hall sensor of direct current unsymmetrical current, design increases ground connection capacitance-resistance loop on dc bus, and the distributed monitoring module on the spot of design specialized is to each DC distribution branch road in the split screen and bus parameter centralized monitor, have real-time monitoring and gather analog data and (measure busbar voltage on the spot in real time, the branch road unsymmetrical current, bus insulation resistance etc.), switching value input (branch switch state, emergency stop valve trip signal or fuse melting signal), control command output (switching value output, can jump branch switch according to a condition distant place) and function such as communication, receive Surveillance center start patrol and examine instruction after, each distributed in-site collecting monitoring module is finished busbar voltage synchronously, data acquisition and maximums such as each branch switch state of each branch road unsymmetrical current, primary Calculation such as weighted average, in time transfer of data is arrived Surveillance center, after receiving Surveillance center's jumping fault branch order, in time selectivity is jumped the fault branch switch or is turn-offed corresponding electronic switch.

9, in the Novel DC system design of above-mentioned proposition, direct current centralized monitoring system (Surveillance center) is finished all data processing and warning by the logic diagram of design, and by distributed monitoring module on the spot, send out the TRIP order to fault branch, the direct current special switch is received after the tripping operation order open failure branch switch (solution four) immediately, begin to selecting correct branch road and tripping fault point branch switch from fault, only need little time, reduced polling period, improved reaction speed, can in time take measures (jumping the fault branch switch), reduce because of string AC and DC ground connection, the probability that direct current faults such as short circuit cause other main equipment accidents to enlarge.By with the distributed communication of monitoring module and rectification module etc. on the spot, real-time sampling and analytical test direct-current power supply ripple coefficient, direct current system voltage is monitored in real time,, judged the quality of storage battery battery pack and charging and discharging of accumulator current measurement and analysis charge-discharge characteristic.Integrate D.C. isolation supervision and route selection, discharge and recharge rectification module monitoring, the direct current centralized monitoring system of the major function of accumulator cell charging and discharging characteristic test and devices such as curve is recorded, the attributional analysis of dc bus power supply.Adopt industrial computer and Chinese Windows operating system, be easy to be familiar with, operation and system programming upgrading etc., capacity according to memory, can store more fault and recorder data, be provided with power down and preserve data function, when preserving fault or each measuring point data (recorder data that comprises a period of time before and after starting) when manually booting the record ripple, realize the high-resolution logout, can draw at this machine, utilize zoom function, can observe the trickleest details.Possess parameter setting, equipment self-inspection, accident record, warning, printing and with the functions such as Ethernet, UBS, serial and speech interface of other system communication.Details are as follows with regard to the logic function of its earthing wire-selecting in Surveillance center:

9.1 mainly contain phenomenons such as dc bus voltage to earth imbalance and ground connection branch road direct current imbalance during to arbitrary branch road ground connection (or string exchanges), by starting and returning the criterion logic, judge by gathering positive and negative busbar voltage to earth degrees of offset (bus is over against the negative voltage to earth value of ground voltage value-bus=busbar voltage deviant): metallic earthing (deviant/rated value is greater than setting value), nonmetal character ground connection (deviant/rated value is in suitable scope), plus earth (deviant is that negative value is less than zero), minus earth (deviant be on the occasion of greater than zero), bus insulation does not normally have ground connection (deviant/rated value is less than setting value), when string exchanges voltage to earth for the crest voltage that exchanges and busbar voltage comprehensively, exchange when crest voltage is judged to string during greater than dc rated voltage (tuning coefficient), select branch road number according to ground connection branch road direct current unsymmetrical current.

Gather and calculate busbar voltage in real time, positive and negative insulation against ground resistance value and insulating resistance value rate of change etc., by starting and returning the criterion logic, and according to bus voltage to earth rate of change, arbitrary value all starts the earthing wire-selecting program greater than the startup value of correspondence in the rate of change of busbar voltage skew and three conditions of insulating resistance value rate of change, start each data acquisition of distributed monitoring module on the spot and calculating simultaneously, and drop into relay K 1 (or K2) respectively ground connection capacitance-resistance loop is devoted negative (or just) bus according to just (or negative) polarity of earth bus, increase ground connection branch road Leakage Current.Start the back or recover the normal value certain hour of delaying time again when busbar voltage and bus insulation, withdraw from the relay K 1 in ground connection capacitance-resistance loop, and the discharge resistance over the ground in connection ground connection capacitance-resistance loop, discharge the energy of electric capacity, drop into when starting in order to next time, ground connection unsymmetrical current sampling period and sampling precision that capacitance-resistance resistance in circuit and capacitance are selected to satisfy each branch road and capacitance-resistance loop get final product.

In relay K 1 (or K2) action during this period of time in (being that the time of moving back is thrown in ground connection capacitance-resistance loop), start all branch road ground connection Leakage Current (direct current unsymmetrical currents of collection synchronously by distributed monitoring module on the spot, as the H1 of Fig. 6 and H11 etc.) and the ground connection Leakage Current (as the H0 of Fig. 6) in ground connection capacitance-resistance loop, the maximum of analytical calculation image data and weighted average (following said earth current, unsymmetrical current or ground connection Leakage Current etc. are two groups of corresponding maximum and weighted averages respectively), and data in time are transferred to Surveillance center's analyzing and processing.

9.2 when DC earthing (or string exchanges) takes place, by 9.1 conditions of Surveillance center according to the aforesaid right requirement, judge and confirm earth fault type, start the earthing wire-selecting process, pressing the branch road string exchanges or the earthing discrimination logic, the ground connection unsymmetrical current that ground connection branch road Hall sensor detects is greater than set point, the ground connection unsymmetrical current that earth-free other branch road Hall sensors detect is less than set point, the ground connection Leakage Current that detects of the Hall sensor in the ground connection capacitance-resistance loop of Tou Ruing is greater than set point simultaneously, selects correct ground connection branch road number.

DC earthing exchanges the differentiation of fault with the direct current string: when interchange sealed in direct current, sampled voltage was a main criterion greater than dc rated voltage (as more than 1.2 times) over the ground.In addition, the detected ground connection unsymmetrical current of the Hall sensor of ground connection branch road will be greater than set point (earth resistance be zero metallic earthing unsymmetrical current), and the detected ground connection Leakage Current of Hall sensor in the ground connection capacitance-resistance loop that installs additional is greater than set point, as the assistant criteria of string interchange.

When dc bus ± KM has ground connection or string to exchange, exchange the differentiation logic with string by busbar grounding, all branch road unsymmetrical currents are all less than the startup value, but the busbar voltage imbalance satisfies condition (deviant/rated value is greater than setting value), the ground connection Leakage Current of the Hall sensor in the ground connection capacitance-resistance loop of Tou Ruing detection simultaneously is also greater than set point, be the busbar grounding fault, in addition simultaneously over the ground sampled voltage exchange main criterion greater than dc rated voltage (as more than 1.2 times) for string, the detected ground connection Leakage Current of Hall sensor in the ground connection capacitance-resistance loop that installs additional is also greater than set point, as the assistant criteria of string interchange.

When 2 above ground connection or string interchange, select other different branch roads number and earth point by above-mentioned same principle and logic, and analyze the earth fault type of each earth point, (comprise warning, jump branch road, record ripple and preserve data and figure etc.) takes appropriate measures.

Above criterion is all judged earth point and earth fault type by maximum and weighted average respectively.By maximum, weighted average and over the ground condition such as sampled voltage satisfy the logic OR relation of setting and report to the police, after satisfying the logical AND relation of setting, again according to open barring conditions such as on off state, device setting, equipment operation situation and plant failure warnings, send out the Wave data of jumping fault branch switch command (or on-off switching tube) and reporting to the police also timely admission accident point, form database file and graphic file.

9.3 for the judgement and the processing that have loop in the direct current system branch road, press the operation of branch road bus loop and differentiate logic, judge that according to the branch switch of 2 buses and the "on" position contact of interconnection switch 2 sections separate branches buses move through the interconnection switch loop.In addition, do not having under the situation of DC earthing, 2 sections independent direct current buses are through the operation of interconnection switch loop, and the electric characteristic before and after the loop operation changes: 2 groups of buses and 2 groups of branch road buses insulation resistance balance over the ground, no bus and branch road ground connection situation; 2 groups of branch road busbar voltages, voltage to earth and insulation against ground are by original unequal identical suddenly; The unsymmetrical current that detects for the Hall sensor of 2 sections independent direct current bus inlet wire branch roads all becomes big suddenly, but each branch road of its subordinate does not all have earth current and unsymmetrical current; The unsymmetrical current direction that the Hall sensor of the inlet wire branch road of loop bus detects is opposite; Come 2 sections separate branches buses of auxiliary judgment to move by maximum and weighted average respectively according to above-mentioned 4 conditions through the interconnection switch loop.And according to situation about judging, take appropriate measures (comprise warning, jump interconnection switch, record ripple and preserve data and figure etc.).

9.4 judgement and processing for short circuit in the direct current system branch road, press branch, short-circuit and differentiate logic, short circuit current is bigger during the branch road direct-current short circuit, the branch current rate of change is also bigger, judge greater than set point greater than set point and branch current rate of change according to branch current: branch road overload, closing pulse electric current and short circuit current, judge the branch, short-circuit fault by maximum and weighted average respectively.Satisfying the logic OR relation of setting by maximum, weighted average design conditions reports to the police, after satisfying the logical AND relation of setting, again according to open barring conditions such as on off state, device setting, equipment operation situation and plant failure warnings, send out and jump fault branch switch command (or on-off switching tube) and warning, the certain hour of delaying time, short circuit branch is tripping not, and this moment branch current still greater than the short circuit set point, according to the situation that is provided with of branch road master switch, jump the branch road master switch.And in time enroll the Wave data of accident point, form database file and graphic file.

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