CN104537161A - Medium voltage distribution network diagnostic analysis method based on power supply safety standards - Google Patents

Abstract

Disclosed is a medium voltage distribution network diagnostic analysis method based on power supply safety standards. The method includes that a power distribution network structure is input, and a connecting relation among lines of a power distribution network is orderly arranged; the power distribution network is subjected to wiring mode analysis; whether conditions of over-limit voltage occur or not after supply transfer is verified through load flow calculation; the lines of the power distribution network are subjected to preprocessing analysis, the lines that can not pass 'N-1' verification are found out and input and stored in a result table, and other data are stored in a component list that requires 'N-1' verification; the lines stored in the component list that requires 'N-1' verification are subjected to 'N-1' verification according to a routing selection method in which switch number is preferential; an 'N-1' verification result table is analyzed in combination with the city power supply safety standards; supply transfer time of different lines is determined, and whether the supply transfer time meets requirement of specific time of the city power supply safety standards or not is determined; measures are given. By means of the medium voltage distribution network diagnostic analysis method based on the power supply safety standards, power supply safety can be subjected to quantitative analysis and guided, and solutions and guiding ideas are provided for the power supply safety of the power distribution network.

Description

A kind of medium voltage distribution network diagnostic analysis method based on power supply safety standard

Technical field

The present invention relates to one.Particularly relate to a kind of medium voltage distribution network diagnostic analysis method based on power supply safety standard.

Background technology

Develop rapidly and the improving constantly of living standards of the people along with socioeconomic, urban distribution network terminal user has higher requirement to Supply Security and power supply reliability level, investment as how appropriateness meets the acceptable Supply Security of user and power supply reliability requirement, becomes subject matter and technological difficulties that China's urban distribution network faces.

Power supply reliability level not only depends on quality and the operation and maintenance level of element, also closely related with element stoppage in transit afterload loss degree, i.e. the Supply Security level of electrical network.Power supply safety criterion must be set scientifically and rationally, make simple and practical power supply safety standard, effectively could solve and improve Supply Security, contradiction between power supply reliability and raising investment economy.Therefore, carefully compare in the urgent need to carrying out the power supply safety standard of domestic and international urban distribution network and analyse in depth, draw advanced theory and ripe method, and according to the actual conditions of China's urban distribution network, utilize data resource and operating experience scientifically and rationally, creatively carry out the research of power supply safety criterion, for the development and perfection of China's urban distribution network power supply safety standard provide theoretical foundation and method guarantee.

Therefore, building the medium voltage distribution network diagnostic analysis method based on power supply safety standard, is practical problems urgently to be resolved hurrily, has good using value and construction value.

Electric system reform experienced by multiple developing stage, tentatively establishes competition, open Regional Electric Market, industrially experienced by need for electricity from " rudiment growth " to the process of " rapid growth ", and forward " fluctuation is risen " stage strides forward.At present, oneself is basicly stable for the electric pressure sequence of urban distribution network, transformer capacity series, and electric network composition is left to be desired, grid automation level and developed country close, power supply reliability level in progressively ascendant trend, but still has a certain distance compared with the urban distribution network of developed country.China's urban electricity supply safety standard is as the basic file of power grid security standard, its core concept is: using the power supply reliability of End-Customer as the object of planning, security of system is associated with client's payload, rank is divided according to load group size, by " N-1 " and " N-1-1 " rule as measure, provide different safety and confidence level that electrical network at different levels should reach.

Urban electricity supply safety standard has deep theory and engineering practice background, and strict logic basis is rigorous, and is the certainty criterion quantized completely, short and sweet, is convenient to direct use.This standard formulates according to China's urban distribution network actual conditions, based on practical operation experience for many years with how to investigate remittance the long and, more meet China's actual conditions and present stage China's power grid architecture performance level, foreign achievement by advanced countries simultaneously, with reference to Britain ERP2/6 standard, have certain international vision, compare with developed country, analysis result has comparability.

In addition, China's grid automation degree is not high.Electric network performance is more perfect, and automaticity is higher, and entire system level is more advanced, and the statistics accuracy provided is higher.Current China electrical network integrated automation degree is not high, and partial data source needs complicate statistics to complete, and comparatively large in data collection phase human factor, partial data authenticity has problems.Therefore build a set of medium voltage distribution network diagnostic method based on power supply safety standard and there is important using value.

Summary of the invention

Technical matters to be solved by this invention is, provide a kind of be applicable to China's electrical network diagnostic work the medium voltage distribution network diagnostic analysis method based on power supply safety standard,

The technical solution adopted in the present invention is: a kind of medium voltage distribution network diagnostic analysis method based on power supply safety standard, comprises the steps:

1) power distribution network network structure is inputted, comprise component information, line length, each load position and load peak, isolating switch and disconnector position, power distribution network communication relationship, first Analysis of Topological Structure is carried out to power distribution network, the communication relationship between combing distribution network line;

2) Connection Mode analysis is carried out to power distribution network, comprise and carry out classification process according to different Connection Modes, be divided into single supply radiation wiring, the wiring of different bus ring type, wiring is got in touch with in segmentation two and wiring is got in touch with in segmentation three, according to different Connection Mode integrating step 1) information data analysis is carried out to power distribution network network;

3) whether there is the situation of voltage out-of-limit to occur after being supplied by Load flow calculation checking turn, comprising:

(1) frontly calculation is pushed: according to the branch road order sequenced, from the branch road be connected with leaf node, utilize leaf node power and corresponding node voltage, initial value is circuit rated voltage, against the direction that power transmits, calculate power attenuation and the power distribution of each section of branch road successively;

(2) voltage of each section of branch road beginning node is calculated;

(3) back substitution computing, according to the backward of the branch road order sequenced, from power supply point, along the direction that power transmits, the voltage of this branch road beginning node utilizing the head end power and (2) of each section of branch road of (1) step gained to calculate, branch road calculates one by one, tries to achieve the voltage of each branch road terminal note;

(4) when the magnitude of voltage of terminal note exceedes the standard voltage value that power supply safety standard specifies, voltage out-of-limit is thought.

4) carry out Preprocessing to distribution network line, by judging distribution network line contact situation, finding out not by the circuit that " N-1 " verifies, and they are input in result table preserve, remainder data is stored in the element table needing " N-1 " to verify;

5) to stored in needing circuit in " N-1 " element table of verifying to carry out " N-1 " verification according to the routing resource that switch number is preferential, the preferential routing resource of described switch number specifically comprises:

(1) formed and need to turn the switch set got in touch with for region;

(2) main the turning of selection carries out turning confession for path;

(3) main turning carries out turning confession for the circuit beyond path;

(4) to causing the loaded portion of voltage out-of-limit to shift;

(5) obtain by " N-1 " School Affairs not by the circuit that " N-1 " verifies, corresponding data result to be recorded respectively, generate " N-1 " check results analytical table.

6) in conjunction with urban electricity supply safety standard to step 5) obtain " N-1 " check results analytical table and analyze, obtain load power stage;

7) according to the average grid switching operation time of power distribution network operation maintenance, and turn for path switch number number, determining different circuit turns for the time, judges to turn whether to reach the requirement of urban electricity supply safety standard official hour for the time;

8) turn and reach the requirement of urban electricity supply safety standard official hour for the time, revision power supply safety standard, turns and does not reach the requirement of urban electricity supply safety standard official hour for the time, transformation circuit, lifting operation and maintenance level, result and step is gathered, obtains diagnosis report.

Step 3) in described in (1) step before push calculation specifically:

A () determines the injecting power of the whole load buses needed for Load flow calculation;

B () supposes that each node voltage initial value is the load voltage value of described each node;

C (), by the injecting power of node and magnitude of voltage, uses the following formula of formula, solve power attenuation and the power distribution of each branch road,

$\mathrm{\Δ}{S}_{\mathrm{ij}}=\frac{P_j^2+Q_j^2}{V_j^2}(R+\mathrm{jX})\×{10}^{-3}---\left(1\right)$

S _ij＝S _j+△S _ij(2)

S _i＝∑S _ij(3)

D (), by outlet head end root node magnitude of voltage and branch road top power, use following equations node voltage, described voltage comprises amplitude and phase angle,

$V_j=\sqrt{{(V_i-\frac{P_{\mathrm{ij}}R+Q_{\mathrm{ij}}X}{V_i})}^2+{\left(\frac{P_{\mathrm{ij}}X-Q_{\mathrm{ij}}R}{V_i}\right)}^2}---\left(4\right)$

${\mathrm{\δ}}_j={\mathrm{\δ}}_i-{\tan }^{-1}(\frac{P_{\mathrm{ij}}X-Q_{\mathrm{ij}}R}{V_i}/V_i-\frac{P_{\mathrm{ij}}R+Q_{\mathrm{ij}}X}{V_i})---\left(5\right)$

S _ijrepresent the applied power of circuit, P represents the active power of circuit, and V represents the magnitude of voltage of circuit, and δ represents the phase angle of voltage, and Q represents the reactive power of circuit, and R represents the resistance of circuit, and X represents the reactance of circuit, and i, j represent that line node is numbered.

E () checks the condition of convergence, terminate to calculate when meeting the condition of convergence, otherwise returns (3) continuation iterative computation.

Step 3) in the calculating of voltage of each section of branch road beginning node described in (2) step be adopt following formula,

$V_j=\sqrt{{(V_i-\frac{P_{\mathrm{ij}}R+Q_{\mathrm{ij}}X}{V_i})}^2+{\left(\frac{P_{\mathrm{ij}}X-Q_{\mathrm{ij}}R}{V_i}\right)}^2}---\left(4\right).$

Step 3) in back substitution computing described in (3) step, be according to the formulae discovery given by (1) step, try to achieve the voltage of each branch road terminal note, described voltage comprises amplitude and phase angle.

Step 8) described in urban electricity supply safety standard in time rule be:

(1) deadline is keeped in repair, according to the difference of maintenance objects, from several hours to several days; (2) undertaken turning for load by manual operation reconstruct electrical network, the time that load restoration power supply station is needed is 3h; (3) straighforward operation reconstruct electrical network, the time 15min that power system restoration is powered; (4) by aut.eq. complete operation 60s.

A kind of medium voltage distribution network diagnostic analysis method based on power supply safety standard of the present invention, by the diagnostic method built in conjunction with urban electricity supply safety standard, quantitative test and guidance can be carried out to power supply safety, excavate the weak link in distribution network line, provide solution and instruction to power distribution network power supply safety.

Accompanying drawing explanation

Fig. 1 is medium voltage distribution network diagnostic process;

Fig. 2 is circuit " N-1 " checking process figure;

Fig. 3 is circuit compare of analysis process flow diagram;

Fig. 4 is comparison determination module determination flow schematic diagram.

Embodiment

Below in conjunction with embodiment and accompanying drawing, a kind of medium voltage distribution network diagnostic analysis method based on power supply safety standard of the present invention is described in detail.

A kind of medium voltage distribution network diagnostic analysis method based on power supply safety standard of the present invention is the security diagnosing China's medium voltage distribution network.

The power supply safety of urban distribution network adopts " N-1 " criterion, that is:

(1) lose in transformer station any one back into line or a step-down transformer time, do not lose load;

(2) pole line in high voltage distribution network, an or cable, or step-down transformer breaks down when stopping transport,

A) under normal circumstances, load is not lost;

B) to break down again under the condition of planned outage stoppage in transit, allow brownout, but should restore electricity in official hour;

(3) pole line in middle voltage distribution networks, an or cable, or in switchgear building a station power distribution transformer break down stop transport time;

A) under normal circumstances, do not have a power failure except faulty section, and brownout must not occur, and the unallowed overload of power-supply unit;

B) in planned outage situation, there occurs again fault and stop transport, allow brownout, but should restore electricity at the appointed time.

(4) in low-voltage network, when a transformer or low-voltage circuit break down, allow brownout, restore electricity after pending fault reparation.

China's urban distribution network power supply safety standard is organized load according to the large young pathbreaker of group load and is divided into A level and has 6 grades altogether to F level, and rank is higher, and the service restoration time after the stoppage in transit of loop is shorter, and load restoration degree is higher.For medium voltage distribution network, load level is A level and B level two class, under the concrete analysis of different group load class is shown in.

A level: group load range is at 0 ~ 2MW.The typical volume of separate unit 10/0.4kV transformer is 0.015 ~ 1MVA.Several (usually choosing less than 5) 10/0.4kV transformer isolation are become a unit by adjacent 2 block switches, and the load of each unit is about 0 ~ 2MW, does not need other current supply circuits.

B level: group load range is at 2 ~ 12MW.Article one, 10kV circuit transmission capacity is 3 ~ 4MW, and the common capacity of separate unit 35/10kV transformer is: 31.5MVA, 20MVA, 16MVA, 5MVA.The typical volume of 35/10kV transformer station is configured to 5*2MVA, 16*2MVA, and institute's bringing onto load is about 5 ~ 10MW.The load that this part provides is about 2 ~ 12MW.

For a power supply rank, " N-1 " stops transport and " N-1-1 " stops transport and may comprise multiple situation, and the most serious " N-1-1 " stoppage in transit situation is: when a loop planned outage, breaks down stoppage in transit in another loop with said function again.Such as, when a transformer circuit (or an inlet wire) planned outage of certain transformer station, another transformer circuit (or another inlet wire) of this transformer station again fault is stopped transport.In order to better meet the standard of security, only the most serious situation is discussed below.

A level (0 ~ 2MW): " N-1 " stops transport, an element fault in segmentation is stopped transport or planned outage, and after having keeped in repair, recovery group load is powered." N-1-1 " stops transport not requirement.

B level (2 ~ 12MW): " N-1 " stops transport, and is divided into 2 kinds of situations a: element fault in (1) segmentation is stopped transport or planned outage, requires to supply group load-2MW in 3h, has keeped in repair rear recovery group load and powered; (2) 10kV circuit trunk On line switch, the equipment failure stoppages in transit such as protection or planned outage, or a transformer circuit fault is stopped transport or planned outage, requires that can recover group load in 3h powers." N-1-1 " stops transport not requirement.

The power supply safety level of urban distribution network needs to be ensured by effective network structure, comprises the many aspects such as standby power supply, spare part, redundancy capacity and grid automation level.In China's urban electricity supply safety standard, power supply safety level and network structure relationship analysis as follows.

A level (0 ~ 2MW): when " N-1 " stops transport, keeped in repair rear recovery group load, this type load does not need standby power supply, and the performance of system depends on the length of breakdown maintenance time.Shorten servicing time, be the only resource ensureing class A user's group system performance as far as possible.

B level (2 ~ 12MW): when " N-1 " stops transport, must in 3h recovery group load-2MW, 3h determined based on artificial reconstruction's electrical network required time that restores electricity, typically refer to and manually complete the time required for manual operation, so this type load group needs standby power supply to scene.The 2MW user be not resumed organizes and is automatically downgraded to A level, after waiting to be repaired completing, restores electricity.

As shown in Figure 1 to 4, a kind of medium voltage distribution network diagnostic analysis method based on power supply safety standard of the present invention, comprises, comprises the steps:

1) power distribution network network structure is inputted, comprise component information, line length, each load position and load peak, isolating switch and disconnector position, power distribution network communication relationship, first Analysis of Topological Structure is carried out to power distribution network, the communication relationship between combing distribution network line;

2) Connection Mode analysis is carried out to power distribution network, comprise and carry out classification process according to different Connection Modes, be divided into single supply radiation wiring, the wiring of different bus ring type, wiring is got in touch with in segmentation two and wiring is got in touch with in segmentation three, according to different Connection Mode integrating step 1) information data analysis is carried out to power distribution network network;

3) whether there is the situation of voltage out-of-limit to occur after being supplied by Load flow calculation checking turn, comprising:

(1) frontly calculation is pushed: according to the branch road order sequenced, from the branch road be connected with leaf node, utilize leaf node power and corresponding node voltage, initial value is circuit rated voltage, against the direction that power transmits, calculate power attenuation and the power distribution of each section of branch road successively;

Calculation is pushed specifically before described:

A () determines the injecting power of the whole load buses needed for Load flow calculation;

B () supposes that each node voltage initial value is the load voltage value of described each node;

C (), by the injecting power of node and magnitude of voltage, uses the following formula of formula, solve power attenuation and the power distribution of each branch road,

$\mathrm{\Δ}{S}_{\mathrm{ij}}=\frac{P_j^2+Q_j^2}{V_j^2}(R+\mathrm{jX})\×{10}^{-3}---\left(1\right)$

S _ij＝S _j+△S _ij(2)

S _i＝∑S _ij(3)

D (), by outlet head end root node magnitude of voltage and branch road top power, use following equations node voltage, described voltage comprises amplitude and phase angle,

$V_j=\sqrt{{(V_i-\frac{P_{\mathrm{ij}}R+Q_{\mathrm{ij}}X}{V_i})}^2+{\left(\frac{P_{\mathrm{ij}}X-Q_{\mathrm{ij}}R}{V_i}\right)}^2}---\left(4\right)$

${\mathrm{\δ}}_j={\mathrm{\δ}}_i-{\tan }^{-1}(\frac{P_{\mathrm{ij}}X-Q_{\mathrm{ij}}R}{V_i}/V_i-\frac{P_{\mathrm{ij}}R+Q_{\mathrm{ij}}X}{V_i})---\left(5\right)$

E () checks the condition of convergence, terminate to calculate when meeting the condition of convergence, otherwise returns (3) continuation iterative computation.

S _ijrepresent the applied power of circuit, P represents the active power of circuit, and V represents the magnitude of voltage of circuit, and δ represents the phase angle of voltage, and Q represents the reactive power of circuit, and R represents the resistance of circuit, and X represents the reactance of circuit, and i, j represent that line node is numbered.

(2) calculate the voltage of each section of branch road beginning node, the calculating of the voltage of each section of described branch road beginning node adopts following formula,

$V_j=\sqrt{{(V_i-\frac{P_{\mathrm{ij}}R+Q_{\mathrm{ij}}X}{V_i})}^2+{\left(\frac{P_{\mathrm{ij}}X-Q_{\mathrm{ij}}R}{V_i}\right)}^2}---\left(4\right);$

(3) back substitution computing, according to the backward of the branch road order sequenced, from power supply point, along the direction that power transmits, the voltage of this branch road beginning node utilizing the head end power and (2) of each section of branch road of (1) step gained to calculate, branch road calculates one by one, try to achieve the voltage of each branch road terminal note, described back substitution computing, according to the formulae discovery given by (1) step, try to achieve the voltage of each branch road terminal note, described voltage comprises amplitude and phase angle;

In order to improve computational accuracy, can repeat the calculating of above (1) ~ (3) step, selecting immediate value is final end value.

Due to the radial structure of power distribution network, the trend can thinking in an outlet changes and can not cause other outlet power flow changings, the relevant outlet after needing the outlet of inspection and network structure change can be selected Partial Load Flow calculating is carried out, to reduce the number of times of Load flow calculation when carrying out Load flow calculation.

(4) when the magnitude of voltage of terminal note exceedes the standard voltage value that power supply safety standard specifies, voltage out-of-limit is thought.

4) carry out Preprocessing to distribution network line, by judging distribution network line contact situation, finding out not by the circuit that " N-1 " verifies, and they are input in result table preserve, remainder data is stored in the element table needing " N-1 " to verify;

5) to stored in needing circuit in " N-1 " element table of verifying to carry out " N-1 " verification according to the routing resource that switch number is preferential, the preferential routing resource of described switch number specifically comprises:

(1) formed and need to turn the switch set got in touch with for region;

(2) main the turning of selection carries out turning confession for path;

(3) main turning carries out turning confession for the circuit beyond path;

(4) to causing the loaded portion of voltage out-of-limit to shift;

(5) obtain by " N-1 " School Affairs not by the circuit that " N-1 " verifies, corresponding data result to be recorded respectively, generate " N-1 " check results analytical table.

The basic data processing module of " N-1 " is divided into three parts: topological analysis, Connection Mode analysis and Load flow calculation analysis.

By the combing to system raw data, for the tidal current computing method proposed in " N-1 " method of calibration, convert and standardization process to the data obtained, making it to become can for the data of algorithm.The status information of communication relationship between main transformer and circuit and switch can be found out, for " N-1 " verify calculation breaker in middle operation choice set provides data encasement by power network topology analysis.Obtain each main transformer by Load flow calculation and confess power, the trend that each element flows through, turn on-load for main transformer is maximum in " N-1 " algorithm, maximum turn of circuit provides data encasement for load etc.

" N-1 " verifies preprocessing part and mainly contains two large functions: one is get rid of obviously not by the data of verification, and they are input in result table, and another one function is the obvious data by verification of screening, in input results table.Remainder data enters in the element table needing verification.

" N-1 " verifies the core that turning solution determining section is " N-1 " checking algorithm module, and its effect the element that need verify in element table is carried out to " N-1 " verification and provides turn for path, and record turns the size for load.Circuit " N-1 " verification is taked to diverse ways to carry out.

6) in conjunction with urban electricity supply safety standard to step 5) obtain " N-1 " check results analytical table and analyze, obtain load power stage;

7) according to the average grid switching operation time of power distribution network operation maintenance, and turn for path switch number number, determining different circuit turns for the time, judges to turn whether to reach the requirement of urban electricity supply safety standard official hour for the time;

8) turn and reach the requirement of urban electricity supply safety standard official hour for the time, revision power supply safety standard, turns and does not reach the requirement of urban electricity supply safety standard official hour for the time, transformation circuit, lifting operation and maintenance level, result and step is gathered, obtains diagnosis report.Time rule in described urban electricity supply safety standard is: (1) maintenance deadline, according to the difference of maintenance objects, from several hours to several days; (2) undertaken turning for load by manual operation reconstruct electrical network, the time that load restoration power supply station is needed is 3h; (3) straighforward operation reconstruct electrical network, the time 15min that power system restoration is powered; (4) by aut.eq. complete operation 60s.

In analysis of results table, there is the check results of different elements, different load, in order to same urban electricity supply safety standard contrasts, need to classify according to load level to it.

(1) typical volume of separate unit 10/0.4kV transformer is 0.015 ~ 1MVA, and that common is 0.8MVA.Several (usually choosing less than 5) 10/0.4kV transformer isolation are become a segmenting unit by adjacent 2 block switches, and the load of each segmenting unit is about 0 ~ 2MW.A level group load is belonged within the scope of this.

Article (2) one, 10kV circuit transmission capacity is 3 ~ 4MW, and the common capacity of separate unit 35/10kV transformer is: 16MVA, 5MVA.The typical volume of 35/10kV transformer station is configured to 5*2MVA, 16*2MVA, and institute's bringing onto load is about 5 ~ 10MW.The load that 10kV circuit and 35/10 substation provide is about 2 ~ 12MW, belongs to B level group load within the scope of this.

This type load meets the specified in more detail in standard in time, turns and also reaches explicitly calling in standard for load.Can think that this part electric network composition reaches safe power supply requirement.

Different according to different regions development degree, if actual conditions are generally short than the time of this standard-required, in the light of actual conditions can carry out correction standard, standard can be played and promote the effect that electric network composition and O&M level improve.This type load is discontented with sufficient related request, is mainly manifested in official hour, can not turn and supply load or turn not meet for load the load required in standard.At this moment, whether inquiry " N-1 " check results analytical table, analyze this subelement by " N-1 " verification.(1) if this subelement can by " N-1 " verification, when illustrating that reason not up to standard is load transfer, artificial reconstruction's process is consuming time longer, needs to improve O&M level; Consider this area's electrical network O&M actual conditions simultaneously, if generally cannot standard-required be reached, then suitably can adjust standard, more meet this area's actual conditions.(2) if this subelement cannot by " N-1 " verification, illustrate that reason not up to standard is the problem of network itself, need to transform electrical network, it is comparatively complicated how to carry out electric network reconstruction, will not discuss in this article.

Provide instantiation below:

MATLAB is the business mathematics software of U.S. MathWorks Company, is one and can be used for algorithm development, data visualization, the advanced techniques computational language of data analysis and numerical evaluation and interactive environment.The present invention is based on MATLAB, achieve the Distribution Network Reliability assessment models containing distributed power source access, the present invention is applied wherein, and based on IEEERBTS power distribution network standard example (Fig. 4), testing authentication has been carried out to effect.

Analyze as example, to this called after A district, region using the somewhere electrical network of transformation.Improved system is as shown in table 1, comprises 3 transformer stations, and each transformer station comprises 2 transformers, outlet totally 88.The contact situation of concrete circuit is as shown in table 2.

(1) A1 station (10kV side power supply capacity 100MVA, load factor is 49%)

A1 station is for 110kV transformer station, and this erect-position, in the middle part of this region, has 32 circuits to power for institute overlay area at present.

(2) A2 station (10kV side power supply capacity 80MVA, load factor is 56.25%)

A2 erect-position is in northeast, one's respective area, and this station owner wants service area to be A district center based on the part rural power grids electricity consumption in the living land of living and the north, district, and this station has 28 circuits at present for institute overlay area and powers.

(3) A3 station (10kV side power supply capacity 80MVA, load factor is 50%)

A3 erect-position in south, this region district, service area be in this region to live, the land used of travel in holiday.This station has 28 circuits at present for institute overlay area and powers.

This region voltage device situation of table 1

Table 2 A district circuit communication relationship

Line fault result of calculation is as shown in table 3.

Table 3A district 10kV line fault analysis result

According to upper table analysis result, be described in detail as follows.

(1) A1 station track route 7, line 8, A2 station track route 37, line 38, line 39, line 40, A3 station track route 67, line 72, line 88.These circuits are single radial lines, do not meet " N-1 " verification, cannot turn on-load when breaking down, and just can restore electricity after needing line fault maintenance by the time.Wherein A1 station track route 8, A2 station track route 37, line 39, line 40, A3 station track route 67, line 72, line 88, these circuits belong to A stage load, and 8 hours servicing time reached safe power supply standard, met the demands; A1 station track route 7, A2 station track route 38 on-loads are comparatively large, belong to B stage load, can not turn the load confessing the standard of reaching when an error occurs, therefore need to carry out transformation and upgrade to this part circuit, make it turn confession time meeting power supply safety prescribed by standard.

(2) A1 station track route 2, line 10, A2 station track route 36.These circuits are single interconnectors, owing to turning for off-capacity, can not turn the whole load of band when a failure occurs it, not meet " N-1 " verification, and there is sub-load needs to restore electricity after breakdown maintenance completes.Need the part turning confession can complete within 2 hours and turn confession, reach power supply safety master gauge and fix time, remainder, after breakdown maintenance completes, namely restores electricity after 8 hours, also meets power supply safety standard.

(3) all the other circuits.All the other circuits are all the circuits having contact, by " N-1 " verification, can complete and turn confession, reach the requirement of power supply safety standard within 2 hours.

Through above-mentioned analysis, the operation and maintenance level in this region can meet power supply safety standard-required, and remove outside 2 circuits urgently improved, remainder can reach standard-required preferably.

A district development is better, has good contact, and get in touch with capacity adequacy between circuit.Under consideration current development case conditions, suitable raising power supply safety standard, promotes that the operation and maintenance level of this area promotes further.Safety standard is revised, obtains result shown in table 4.

Table 4 is applicable to the power supply safety standard correction in A district

Sequence number	Time standard is classified	Release time
			1	Breakdown maintenance completes required averaging time	5 hours
2	Based on the averaging time that artificial reconstruction's power system restoration power supply station needs	2 hours
			3	Based on the averaging time that remote control reconstruct power system restoration power supply station needs	15 minutes
4	Complete the averaging time required for automatic switchover	60s

Claims (5)

1., based on a medium voltage distribution network diagnostic analysis method for power supply safety standard, it is characterized in that, comprise the steps:

1) power distribution network network structure is inputted, comprise component information, line length, each load position and load peak, isolating switch and disconnector position, power distribution network communication relationship, first Analysis of Topological Structure is carried out to power distribution network, the communication relationship between combing distribution network line;

2) Connection Mode analysis is carried out to power distribution network, comprise and carry out classification process according to different Connection Modes, be divided into single supply radiation wiring, the wiring of different bus ring type, wiring is got in touch with in segmentation two and wiring is got in touch with in segmentation three, according to different Connection Mode integrating step 1) information data analysis is carried out to power distribution network network;

3) whether there is the situation of voltage out-of-limit to occur after being supplied by Load flow calculation checking turn, comprising:

(1) frontly calculation is pushed: according to the branch road order sequenced, from the branch road be connected with leaf node, utilize leaf node power and corresponding node voltage, initial value is circuit rated voltage, against the direction that power transmits, calculate power attenuation and the power distribution of each section of branch road successively;

(2) voltage of each section of branch road beginning node is calculated;

(3) back substitution computing, according to the backward of the branch road order sequenced, from power supply point, along the direction that power transmits, the voltage of this branch road beginning node utilizing the head end power and (2) of each section of branch road of (1) step gained to calculate, branch road calculates one by one, tries to achieve the voltage of each branch road terminal note;

(4) when the magnitude of voltage of terminal note exceedes the standard voltage value that power supply safety standard specifies, voltage out-of-limit is thought.

4) carry out Preprocessing to distribution network line, by judging distribution network line contact situation, finding out not by the circuit that " N-1 " verifies, and they are input in result table preserve, remainder data is stored in the element table needing " N-1 " to verify;

5) to stored in needing circuit in " N-1 " element table of verifying to carry out " N-1 " verification according to the routing resource that switch number is preferential, the preferential routing resource of described switch number specifically comprises:

(1) formed and need to turn the switch set got in touch with for region;

(2) main the turning of selection carries out turning confession for path;

(3) main turning carries out turning confession for the circuit beyond path;

(4) to causing the loaded portion of voltage out-of-limit to shift;

(5) obtain by " N-1 " School Affairs not by the circuit that " N-1 " verifies, corresponding data result to be recorded respectively, generate " N-1 " check results analytical table;

6) in conjunction with urban electricity supply safety standard to step 5) obtain " N-1 " check results analytical table and analyze, obtain load power stage;

7) according to the average grid switching operation time of power distribution network operation maintenance, and turn for path switch number number, determining different circuit turns for the time, judges to turn whether to reach the requirement of urban electricity supply safety standard official hour for the time;

8) turn and reach the requirement of urban electricity supply safety standard official hour for the time, revision power supply safety standard, turns and does not reach the requirement of urban electricity supply safety standard official hour for the time, transformation circuit, lifting operation and maintenance level, result and step is gathered, obtains diagnosis report.

2. a kind of medium voltage distribution network diagnostic analysis method based on power supply safety standard according to claim 1, is characterized in that, step 3) in described in (1) step before push calculation specifically:

A () determines the injecting power of the whole load buses needed for Load flow calculation;

B () supposes that each node voltage initial value is the load voltage value of described each node;

C (), by the injecting power of node and magnitude of voltage, uses the following formula of formula, solve power attenuation and the power distribution of each branch road,

${\mathrm{\ΔS}}_{\mathrm{ij}}=\frac{P_j^2+Q_j^2}{V_j^2}(R+\mathrm{jX})\×{10}^{-3}---\left(1\right)$

S _ij＝S _j+△S _ij(2)

S _i＝∑S _ij(3)

D (), by outlet head end root node magnitude of voltage and branch road top power, use following equations node voltage, described voltage comprises amplitude and phase angle,

$V_j=\sqrt{{(V_i-\frac{P_{\mathrm{ij}}R+Q_{\mathrm{ij}}X}{V_i})}^2+{\left(\frac{P_{\mathrm{ij}}X-Q_{\mathrm{ij}}R}{V_i}\right)}^2}---\left(4\right)$

${\mathrm{\δ}}_j={\mathrm{\δ}}_i-{\tan }^{-1}(\frac{P_{\mathrm{ij}}X-Q_{\mathrm{ij}}R}{V_i}/V_i-\frac{P_{\mathrm{ij}}R+Q_{\mathrm{ij}}X}{V_i})---\left(5\right)$

S _ijrepresent the applied power of circuit, P represents the active power of circuit, and V represents the magnitude of voltage of circuit, and δ represents the phase angle of voltage, and Q represents the reactive power of circuit, and R represents the resistance of circuit, and X represents the reactance of circuit, and i, j represent that line node is numbered.

E () checks the condition of convergence, terminate to calculate when meeting the condition of convergence, otherwise returns (3) continuation iterative computation.

3. a kind of medium voltage distribution network diagnostic analysis method based on power supply safety standard according to claim 1, is characterized in that, step 3) in the calculating of voltage of each section of branch road beginning node described in (2) step be adopt following formula,

$V_j=\sqrt{{(V_i-\frac{P_{\mathrm{ij}}R+Q_{\mathrm{ij}}X}{V_i})}^2+{\left(\frac{P_{\mathrm{ij}}X-Q_{\mathrm{ij}}R}{V_i}\right)}^2}---\left(4\right).$

4. a kind of medium voltage distribution network diagnostic analysis method based on power supply safety standard according to claim 1, it is characterized in that, step 3) in back substitution computing described in (3) step, according to the formulae discovery given by (1) step, try to achieve the voltage of each branch road terminal note, described voltage comprises amplitude and phase angle.

5. a kind of medium voltage distribution network diagnostic analysis method based on power supply safety standard according to claim 1, is characterized in that, step 8) described in urban electricity supply safety standard in time rule be:

(1) deadline is keeped in repair, according to the difference of maintenance objects, from several hours to several days; (2) undertaken turning for load by manual operation reconstruct electrical network, the time that load restoration power supply station is needed is 3h; (3) straighforward operation reconstruct electrical network, the time 15min that power system restoration is powered; (4) by aut.eq. complete operation 60s.