A kind of pollution test extra-high voltage direct-current voltage generator
Technical field
The present invention relates to a kind of DC voltage generator, in particular to a kind of super, extra-high voltage insulator pollution test is used
Extra-high voltage direct-current voltage generator.
Background technology
The determination of the external insulation level of extra-high voltage electric transmission and transformation equipment will consider following three kinds of voltage:Lightning surge, operation
Overvoltage and pollution flashover voltage.Since extra-high voltage electric transmission and transformation system takes a variety of pressure limiting measures and the improvement of breaker performance,
Lightning surge and switching overvoltage may be limited to acceptable level, the external insulation water of line insulator and change of current station equipment
The flat dirty tolerance level depending under working voltage.Pollution flashover becomes the major control factors of project of transmitting and converting electricity external insulation design.With
Plains region is compared, and the external insulation pollution flashover problem of high altitude localities merits attention especially.
Super, extra-high voltage direct-current transmission has the advantages that stability is high, and governing speed is flexible, remote transmission, so in state
It is inside and outside to be used widely.However, due to being mostly long distance powedr transmission, super, extra-high voltage transmission line line channel passes through area
Mostly environment is complicated, such as:The area of Yun Guang ± 800kV extra-high voltage direct-current transmission engineerings 1/3 is plateau;Burner zone to Shanghai, breathe out
For ± 800kV the extra-high voltage direct-current transmission engineerings such as Mi Nan-Zhengzhou, Xi Luodu-West Zhejiang Province across more provinces and cities, line channel environment is multiple
It is miscellaneous, it is more to be related to factor.The lending analysis such as pollution flashover, the ice sudden strain of a muscle of insulator, can not carry out simulation calculating, also not by numerical simulation
It can simply be solved by increasing nargin by the design experiences of previous circuit.Extra-high voltage grade higher, transmission line capability is big, once
Pollution flashover accident occurs, consequence is quite serious;The research of filth insulation characteristic is for UHVDC Transmission Lines tower head size etc.
The determination of external insulation parameter is particularly significant, and the experiment of extra-high voltage direct-current insulator contamination is established in an urgent demand, to study super, extra-high voltage
The Flashover Characteristics of insulator.
± 1100kV extra-high voltage direct-current transmission technologies are the new peaks of HVDC Transmission Technology, in overlength distance power transmission project
Play irreplaceable important function.In order to ensure the safety of ± 1100kV extra-high voltage direct-current transmission engineerings, at the same take into account through
Ji property, it is necessary to which the filth insulation experimental study for carrying out extra-high voltage insulator material object under full-scale conditions is used for engineering to obtain
The reference data of design.
In order to simulate high-capacity direct Flow Line working voltage, direct current pollution test power supply must assure that test product is larger in appearance
Under current conditions, experiment power supply output voltage keeps relative stability, to ensure the accuracy of test data.± 1100kV is completely new
Extra-high voltage direct-current voltage class, external insulation experiment is carried out to test products such as the insulators of the voltage class, needs large capacity, high electricity
The DC voltage generator that pressure, low output voltage fluctuate, test voltage fluctuation is bigger, resistance to carrying out test product voltage using lifting and lowering method
The data dispersibility obtained when being put to the test is bigger, and the deviation of relative standard the also high, is unfavorable for carrying out engineering design.The prior art
Middle experiment power supply voltage class is up to ± 1000kV, cannot meet the external insulation examination of ± 1100kV and above engineering
Test Research Requirements;On the other hand, experiment power supply is in the single test for generating test product voltage resistance results, and output voltage pressure drop is not
More than 10%, opposite voltage overshoot is no more than 10% ", and output voltage fluctuation is larger, causes test result not accurate enough.
Invention content
In order to solve the above problem in the presence of the prior art, the present invention provides a kind of pollution test extra-high voltage direct-current
Voltage generator, the DC voltage generator can generate the DC voltage between -1600KV~+1600KV, for super, extra-high voltage is exhausted
Edge pollution test provides power supply, and in the single test for generating test product voltage resistance results, output voltage pressure drop is no more than
5%, opposite voltage overshoot is no more than 5%, can meet the external insulation experimental study of ± 1100kV and above engineering and need
It asks, improves the accuracy and reliability of pollution test result.
Technical solution provided by the invention is:A kind of pollution test extra-high voltage direct-current voltage generator, including pressure regulator,
Group of Silicon Controlled Rectifier, step-up transformer, voltage-doubler rectifier, voltage and current measurement unit, Group of Silicon Controlled Rectifier voltage-regulation voltage-stabilization control device and behaviour
Make console;
It is theed improvement is that:The input terminal of the pressure regulator is connected by prime switchgear with alternating-current voltage source, defeated
Outlet is connected by rear class switchgear with the input terminal of Group of Silicon Controlled Rectifier;The output end of the Group of Silicon Controlled Rectifier and step-up transformer it is defeated
Entering end to be connected, the output end of the step-up transformer is connected by harmonics resistance with the input terminal of the voltage-doubler rectifier,
The output end of the voltage-doubler rectifier is connected by direct current protecting resistance with voltage and current measurement unit;The voltage and current measurement
Unit is connected with the Group of Silicon Controlled Rectifier voltage-regulation voltage-stabilization control device and the operating console respectively by signal acquisition circuit, institute
Group of Silicon Controlled Rectifier voltage-regulation voltage-stabilization control device is stated by overvoltage protector BOD to be connected with the control pole of the Group of Silicon Controlled Rectifier;The behaviour
The pressure regulator and the Group of Silicon Controlled Rectifier voltage-regulation voltage-stabilization control device are separately connected and sent a signal to as console.
Preferably, the operating console monitors the input electricity of the pressure regulator by current transformer and voltage transformer
The input current and voltage of stream and voltage, the output current of the switchgear and voltage and the booster;And pass through electric current
Voltage measurement unit and signal acquisition circuit monitor the output voltage and electric current of the voltage-doubler rectifier;
The operating console judges overvoltage or current signal according to the input voltage or electric current of the step-up transformer,
When the input voltage of the step-up transformer or excessive electric current, overvoltage or current signal are sent to by the operating console
The Group of Silicon Controlled Rectifier voltage-regulation voltage-stabilization control device, the Group of Silicon Controlled Rectifier voltage-regulation voltage-stabilization control device is by controlling the Group of Silicon Controlled Rectifier
Turn on and off and carry out overvoltage or overcurrent protection.
Preferably, the operating console is human-computer interaction interface;The operating console is for setting direct current pressure
The output voltage values of raw device, and the pressure regulator and the Group of Silicon Controlled Rectifier voltage-regulation voltage-stabilization control device are sent a signal to respectively;
The pressure regulator automatically adjusts input-output ratio according to the output voltage values;
The Group of Silicon Controlled Rectifier voltage-regulation voltage-stabilization control device exports corresponding trigger pulse according to the output voltage values, and leads to
It crosses after the overvoltage protection of the overvoltage protector BOD and is output to the control pole of the Group of Silicon Controlled Rectifier, it is described silicon-controlled to control
The turn-on and turn-off of group, adjust the input voltage and electric current of the booster.
Preferably, the Group of Silicon Controlled Rectifier includes two groups of one-way SCRs;The one of which list of two groups of one-way SCRs
To silicon-controlled including sequentially connected silicon-controlled V11, V12, V13, V14, V15 and V16, another group of one-way SCR includes successively
Silicon-controlled V21, V22, V23, V24, V25 and V26 of connection;
Described silicon-controlled V11, V12, V13, V14, V15 and V16 respectively with described silicon-controlled V21, V22, V23, V24, V25
It is connected with V26 inverse parallels, forms six groups of bidirectional triode thyristors;
The anode of the silicon-controlled V11 is the input terminal of the Group of Silicon Controlled Rectifier, and the cathode of the silicon-controlled V16 can for described in
Control the output end of silicon group.
Further, overvoltage protector BOD include respectively with bidirectional triode thyristor V11 and V21, bidirectional triode thyristor V12 and V22,
Bidirectional triode thyristor V13 and V23, bidirectional triode thyristor V14 and V24, bidirectional triode thyristor V15 and V25 and bidirectional triode thyristor V16 and
Overvoltage protector BOD1, BOD2, BOD3, BOD4, BOD5 and BOD6 that the cathode of V26 is connected with control pole.
Further, Group of Silicon Controlled Rectifier voltage-regulation voltage-stabilization control device includes PLC controller and pulse signal generator;
The pulse signal generator include respectively with the overvoltage protector BOD1, BOD2, BOD3, BOD4, BOD5, with
And BOD6 correspond to connected pulse signal generator A1 and A2, A3 and A4, A5 and A6, A7 and A8, A9 and A10 and A11 and
A12;
The PLC controller respectively with the pulse signal generator A1, A2, A3, A4, A5, A6, A7, A8, A9, A10,
A11 is connected with A12.
Further, the Group of Silicon Controlled Rectifier voltage-regulation voltage-stabilization control device receives the electricity at product to be tested both ends by PLC controller
Pressure and electric current, and the pulse signal generator is controlled according to the voltage and current value and generates trigger pulse, the triggering arteries and veins
To the silicon-controlled control pole, triggering is described silicon-controlled to be switched on or off for output after overvoltage protector BOD synthesis for punching, from
And control the input voltage of the step-up transformer.
Preferably, the voltage and current measurement unit includes divider and current sampling resistor;
The voltage-doubler rectifier includes capacitor tower C0, capacitor tower C0 ', high voltage silicon rectifier stack D1, high voltage silicon rectifier stack D2;
One end of the capacitor tower C0 connects with the cathode of the anode of the high voltage silicon rectifier stack D1 and the high voltage silicon rectifier stack D2 respectively
It connects, the both ends of the capacitor tower C0 ' are separately connected the anode of the cathode and the high voltage silicon rectifier stack D2 of the high voltage silicon rectifier stack D1;
It connects between the other end of the capacitor tower C0 and the output end of the step-up transformer harmonics resistance;
The anode of the high voltage silicon rectifier stack D2 is separately connected another output end and ground of the step-up transformer;
The cathode of the high voltage silicon rectifier stack D1 is connect with one end of the direct current protecting resistance, the direct current protecting resistance it is another
One end is separately connected one end of the divider and one end of product to be tested;
The other end of the product to be tested is connect with one end of the current sampling resistor, the current sampling resistor it is another
One end is separately connected the other end and ground of the divider.
Further, the High Level AC Voltage that the step-up transformer exports is converted to high voltage direct current by the voltage-doubler rectifier
It is exported to product to be tested by direct current protecting resistance;
The divider acquires the voltage at the product to be tested both ends, and the voltage is transmitted by voltage collection circuit
Group of Silicon Controlled Rectifier voltage-regulation voltage-stabilization control device, the current sampling resistor acquisition is given to flow through the electric current of the product to be tested and will be described
Electric current is transferred to Group of Silicon Controlled Rectifier voltage-regulation voltage-stabilization control device by current collection circuit.
Further, the current sampling resistor includes five sampling resistors, and five sampling resistor both ends are in parallel respectively
It is sequentially connected in series after fast recovery diode, transient voltage suppressor TVP and zinc oxide;
The fast recovery diode, the transient voltage suppressor TVP and the zinc oxide are for realizing described
The overvoltage protection of sampling resistor.
Further, power frequency supply by ground potential restraining device respectively with the voltage sampling circuit and the current sample
Circuit is connected, the working power for providing the voltage sampling circuit and the current sampling circuit;When preventing line flashover
Counterattack and ground potential are too high to the voltage sampling circuit and described caused by voltage sampling circuit and current sampling circuit
Destruction caused by current sampling circuit.
Further, the ground potential restraining device includes inductance L1, L2, L3, L4, L5 and L6, resistance R1, R2, R3, R4 and
RL, Zinc-oxide piezoresistor Re1, Re2 and Re3 and capacitor tower C1, C2, C3 and C4;
The inductance L1, L2, L3, the resistance RL, described inductance L6, L5 and L4 are sequentially connected;The inductance L1's is another
The other end of one end and the inductance L4 are the input terminal for connecting power frequency supply;The both ends of the resistance RL are connection voltage sample
The output end of circuit and current sampling circuit;
The resistance R1, described capacitor tower C1, C2 and the resistance R2 are sequentially connected;The other end of the resistance R1 is distinguished
It is connected with the resistance Re1 and one end and the connecting pin of the inductor L1 and the inductance L2, the resistance R2's is another
End is connected with one end of the resistance Re2 and the connecting pin of the inductance L4 and the inductance L5 respectively;The resistance Re2
The other end be connected respectively with the other end of the resistance Re1, the connecting pin of the capacitor tower C1 and C2 and ground;
The resistance R3, described capacitor tower C3, C4 and the resistance R4 are sequentially connected;The other end of the resistance R3 is distinguished
It is connected with the resistance Re3 and one end and the connecting pin of the inductor L2 and the inductance L3, the resistance R4's is another
End is connected with the other end of the resistance Re3 and the connecting pin of the inductance L5 and the inductance L6 respectively;The capacitor tower
The connecting pin of C1 and C2 is grounded.
Preferably, the input voltage phase of the Group of Silicon Controlled Rectifier voltage-regulation voltage-stabilization control device monitoring and the pressure regulator
And the output voltage phase of the voltage-doubler rectifier, the angle of flow of the Group of Silicon Controlled Rectifier is adjusted according to comparison result, makes institute
Input voltage phase is stated to be consistent with the output voltage phase.
Compared with immediate technical solution, the present invention has following marked improvement:
1) DC voltage generator provided by the invention is easy to operate, flexible, and cost of investment is low, and reliability is high, stability
Good, in the single test for generating test product voltage resistance results, output voltage pressure drop is no more than 5%, and opposite voltage overshoot does not surpass
5% is crossed, the experiments such as can meet the filth of UHVDC Transmission Lines insulator and current conversion station external insulation equipment, icing, drench with rain and grinding
Study carefully the requirement to experiment power supply, improve the accuracy and reliability of pollution test result, to build super, extra-high voltage direct-current transmission
Provide important technical support;
2) in the output end series AC protective resistance of booster, the output of voltage-doubler rectifier terminates direct current protecting resistance,
Improve the resistance to shorting performance of equipment;
3) present invention generates trigger pulse by PLC controller control wave generator, using overvoltage protector
BOD is exported to the control pole of Group of Silicon Controlled Rectifier, it is therefore prevented that overvoltage protector BOD loses pulse phenomenon;
4) present invention acquires the output voltage and electric current of voltage-doubler rectifier by divider and current sampling resistor, then passes through
Voltage collection circuit and current collection circuit, which export, gives Group of Silicon Controlled Rectifier voltage-regulation voltage-stabilization control device, current feedback and Voltage Feedback structure
At two close cycles voltage-regulating system, improve the stability of complete equipment;
5) current sampling resistor realizes the measurement of 5 range shelves with five sampling resistors, and each sampling resistor both ends are simultaneously
Three-level over-voltage protection element is joined, ensure that measuring system is safe and reliable, it can be achieved that the pulse-width only shock pulse of 10 μ s
Accurate measurement;
6) power frequency supply is connected by ground potential restraining device with voltage collection circuit and current collection circuit, for providing
The working power of voltage collection circuit and current collection circuit, to voltage and current measurement part when preventing monitored line flashover
Caused by counterattack and ground potential raise the destruction to system.
Description of the drawings
Fig. 1 is the hardware block diagram of DC booster provided by the invention;
Fig. 2 is the circuit diagram of DC booster provided by the invention;
Fig. 3 is the structural schematic diagram that Group of Silicon Controlled Rectifier voltage-regulation voltage-stabilization control device is connected with Group of Silicon Controlled Rectifier in Fig. 1;
Fig. 4 is the circuit diagram that sampling resistor installs three-level protective additional;
Fig. 5 is the structure principle chart of ground potential restraining device.
Specific implementation mode
For a better understanding of the present invention, present disclosure is done further with example with reference to the accompanying drawings of the specification
Explanation.
As shown in Figure 1 and Figure 2:The nominal input voltage of DC voltage generator provided by the invention is exchange 10KV, defeated
It is adjustable to go out -1600KV~+1600KV, output-current rating 2A, electric current be 500mA, the duration be no more than 0.5 second situation
Under, test product voltage drop is less than 5%, and voltage overshoot is less than 5%.
DC voltage generator is mainly become by operating console, pressure regulator, Group of Silicon Controlled Rectifier voltage-regulation voltage-stabilization control device, boosting
Depressor, voltage-doubler rectifier and measuring system composition;
Group of Silicon Controlled Rectifier outputs and inputs termination AC-DC conversion switch, need to can when carrying out DC voltage and generating experiment
Control silicon group is connected between rear class switchgear and step-up transformer.
The allomeric function of DC voltage generator is as follows:
Operating console setting DC voltage generator needs the target voltage values exported, then sends a signal to silicon-controlled
Group voltage-regulation voltage-stabilization control device and pressure regulator;And the switching signal of prime switchgear and rear class switchgear is provided, by being manually closed
Prime switchgear and rear class switchgear;
Pressure regulator carries out coarse adjustment according to target voltage values, automatically adjusts the input-output ratio of itself;Front stage switchgear closes
After conjunction, Group of Silicon Controlled Rectifier voltage-regulation voltage-stabilization control device sends out trigger pulse, and the trigger pulse is after overvoltage protector BOD synthesis
It is output to the control pole of Group of Silicon Controlled Rectifier, the primary side input current of adjusting step-up transformer is switched on or off by triggering Group of Silicon Controlled Rectifier
And voltage;The alternating current of step-up transformer output is input to voltage-doubler rectifier through harmonics resistance, will by voltage-doubler rectifier
Alternating current is converted to direct current, and direct current is output to product to be tested insulator by direct current protecting resistance, and it is exhausted to carry out product to be tested
Edge is in Flashover Characteristics research super, under extra-high voltage.Systematic survey measures the voltage and current at product to be tested both ends, and will measure
Voltage and current signals feed back to operating console and controllable groups voltage-regulation voltage-stabilization control device, by Group of Silicon Controlled Rectifier voltage-regulation voltage-stabilization control
Device processed is turned on and off according to feedback signal dynamic regulation is silicon-controlled;Voltage and current of the operating console to test product both ends
Amplitude and waveform are shown and are recorded.
It is the concrete function introduction of DC voltage generator each section below:
1) operating console
Operating console includes mainly human-computer interaction interface, uses remote controlled manner;Main realization target voltage values
Setting, controls the lifting of pressure regulator, the functions such as monitoring and over-voltage over-current protection to each section voltage and current.
As shown in Figure 2:Operating console by current transformer and voltage transformer monitor pressure regulator input voltage and
The input voltage and electric current of electric current, the output voltage of rear class switchgear and electric current, booster;Pass through divider and current sample electricity
The voltage and current at resistance monitoring product to be tested both ends.It can carry out accident analysis and diagnosis.
Operating console carries out overvoltage and overcurrent protection by monitoring input voltage and the C phases input current of booster,
When the voltage and current of monitoring is excessive, operating console sends protection signal to Group of Silicon Controlled Rectifier voltage-regulation voltage-stabilization control device, leads to
Group of Silicon Controlled Rectifier voltage-regulation voltage-stabilization control device control Group of Silicon Controlled Rectifier is crossed to turn on and off to carry out overvoltage and overcurrent protection.
Operating console by monitoring the voltage and current at product to be tested both ends, can dynamic regulation pressure regulator output electricity
Pressure, maintains the output of DC voltage generator to stablize.
2) Group of Silicon Controlled Rectifier voltage-regulation voltage-stabilization control device
As shown in Figure 3:Group of Silicon Controlled Rectifier voltage-regulation voltage-stabilization control device mainly include PLC controller and pulse signal generator,
It is by the changing rule of divider and current sampling resistor real-time tracking product to be tested both end voltage and electric current, in conjunction with Fuzzy Control
Algorithm processed carries out operation to value of feedback, finally provides the controlling value of matrixing, real-time control turn on thyristors, binding operation control
Platform processed is exported according to product to be tested both end voltage and current control pressure regulator in real time, can effectively maintain DC voltage generator defeated
Go out voltage stabilization.
In addition, Group of Silicon Controlled Rectifier voltage-regulation voltage-stabilization control device can also be by comparing the input voltage phase of pressure regulator and tested
The voltage-phase at product both ends, the silicon-controlled angle of flow of dynamic regulation, makes input and output phase sequence always, realizes the stabilization of voltage.
3) Group of Silicon Controlled Rectifier
As shown in Figure 3:The concatenated forward and reverse connection of one-way SCR of Group of Silicon Controlled Rectifier 6 forms six groups of bidirectional triode thyristors,
Every group of bidirectional triode thyristor is sent out by two pulse signals of one piece of Overvoltage Protection Board BOD and Group of Silicon Controlled Rectifier voltage-regulation voltage-stabilization control device
Raw device connection generates trigger pulse by the PLC controller control wave generator of Group of Silicon Controlled Rectifier voltage-regulation voltage-stabilization control device,
It is exported respectively to silicon-controlled cathode and control pole after Overvoltage Protection Board BOD synthesis;Trigger silicon-controlled be switched on or off.
4) pressure regulator
Pressure regulator is single-phase column structure, nominal input voltage:10kV, output voltage 0-10.5kV, output-current rating
457A, rated capacity:4800kVA, under different output voltages, voltage waveform distortion is small, output voltage waveforms distortion it is small (≤
3%), total harmonic component is less than 0.4%.Short-circuit impedance is small, and in the 50%-100% ranges of nominal tension, short-circuit impedance is less than
5%.
Pressure regulator can adjust the input-output ratio of itself according to the signal dynamics that operating console is sent, to maintain direct current
Voltage generator output voltage stabilization meets the experiment demand under different voltages grade.
5) voltage-doubler rectifier
The input of voltage-doubler rectifier terminates harmonics resistance, output termination direct current protecting resistance, harmonics resistance R7
Resistance value be 10k Ω, direct current protecting resistance R0 be 18Kk Ω;The multiplication of voltage capacitor tower C0=2 μ F of voltage-doubler rectifier, filter capacitor tower
The μ of C0 '=1 F;
Multiplication of voltage capacitor tower C0 and filter capacitor tower C0 ' is connected with ground connection discharge switch, when after the test, multiplication of voltage capacitor tower
There is also a large amount of charges by C0 and filter capacitor tower C0 ', in order to ensure safety, it is necessary to by multiplication of voltage capacitor tower C0 and filter capacitor tower
The quantity of electric charge on C0 ' all drains, and traditional ground connection discharge switch protective resistance of partial earthing discharge switch in electric discharge goes out
Existing breakdown between adjacent turns, over time, protective resistance can be burnt out;The present invention is using the noninductive glaze resistance of high pressure as earthing switch
Protective resistance;Often section earthing switch uses drop hammer type knot by the pressure test of 300kV and conductive discharge experiment, overall structure
Structure is driven by cylinder and is controlled, and improves ground connection discharge switch reliability of operation.
6) measuring system
Measuring system includes mainly divider, current sampling resistor Ra, the voltage sampling circuit being connect with divider and electricity
Flow the current sampling circuit composition of sampling resistor connection;
Divider includes high-voltage arm R5 and low-voltage arm R6;Voltage for measuring product to be tested both ends, measuring signal warp
It is exported respectively to the PLC controller and operating console of Group of Silicon Controlled Rectifier voltage-regulation voltage-stabilization control device after voltage collection circuit acquisition;
Realize the closed-loop control of voltage.
As shown in Figure 4:Current sampling resistor Ra includes five resistance, and 3 grades of overvoltage protections of each resistor coupled in parallel are (fast to restore
Diode, transient voltage suppressor TVP, zinc oxide), it is ensured that measuring system is safe and reliable.5 amounts of current sampling resistor point
Journey shelves realize the large scale and high accuracy measurement to transient current 1mA -90A, 500kpbs/s are up to using rate for the first time.It can be real
The accurate measurement of the existing pulse-width only shock pulse of 10 μ s.Ns grades of automatic switchover can be achieved in each range shelves of system, protects
Demonstrate,prove the measurement essence in 1mA -50mA, 50mA -300mA, 300mA -1.5A, 1.5A -10A, each range abilities of 10A -90A
Degree.Its measuring signal exports after current collection circuit acquires respectively to the PLC controls of Group of Silicon Controlled Rectifier voltage-regulation voltage-stabilization control device
Device and operating console realize the closed-loop control of electric current.
7) ground potential restraining device
As shown in Figure 5:Ground potential restraining device is connected between power supply and voltage collection circuit and current collection circuit,
Working power for providing measuring system, the power supply of protection system is from interference, when preventing monitored line flashover
Caused by counterattack and ground potential raise the destruction to system.
Ground potential restraining device is mainly made of voltage-suppressing circuit and filter circuit.Voltage-suppressing circuit is by zinc oxide pressure
Quick resistance is constituted, and effect is to inhibit surge voltage and electric current;Filter circuit is made of LC low-pass filter circuits, for filtering electricity
High fdrequency component in pressure, current signal.
Wherein Zinc-oxide piezoresistor Re1, Re2 is connected between the firewire, zero curve and earth point of power supply, and Re3 is connected on power supply
Firewire and zero curve between, they inhibit supply voltage and current surge to load RL impact.Capacitor tower C1-C4 will connect
The voltage and supply voltage in place link together, and line voltage is made to be associated with ground potential, it is therefore prevented that the suddenly change pair of ground potential
The influence of power supply.The second order lc circuit being made of inductance and capacitance effectively inhibits power supply ripple, has filtered out the high frequency in circuit
Clutter and interference.Resistance R1-R4 is sealed in circuit, and LC filter circuits generate self-oscillation in order to prevent.Pass through zinc oxide pressure-sensitive
The reasonable combination of resistance and LC filter circuits realizes the effective protection to system power supply, ensure that being normally carried out for measurement.For
Power supply is exported after inductance L1 and L4 input by the both ends resistance RL, and work is provided to voltage sampling circuit and current sampling circuit
Make power supply.
It these are only the embodiment of the present invention, be not intended to restrict the invention, it is all in the spirit and principles in the present invention
Within, any modification, equivalent substitution, improvement and etc. done are being applied within pending scope of the presently claimed invention.