CN103078318B - Overvoltage improvement method on basis of historical data of overhead power transmission line - Google Patents

Abstract

The invention discloses an overvoltage improvement method based on historical data of overhead transmission lines. , as well as the type and structural size of the wires and overhead ground wires selected for the transmission line, using electromagnetic transient analysis to calculate the zero-sequence and positive-sequence resistance, inductance, and capacitance of the line, and then comprehensively calculate the overvoltage under various operating modes , a method for improving the overvoltage is proposed, so that the corresponding strategy can be called in a targeted manner, which is beneficial to realize the differential design of the circuit.

Description

An Overvoltage Improvement Method Based on Historical Data of Overhead Transmission Lines

technical field

The invention belongs to the technical field of power grid transmission lines, and relates to an overvoltage improvement method for overhead transmission lines.

Background technique

In recent years, insulator flashover tripping accidents have occurred many times in the transmission lines of various voltage levels in the power grid, especially in the Northwest Power Grid, which has had a major impact on the reliability of power supply in the power grid and caused great economic losses; according to the analysis of flashover accidents, the pollution accumulated on the surface of insulators It is one of the main causes of flashover. In view of the randomness, variability and multiple influencing factors of pollution, the calculation of line overvoltage is particularly important. There are few similar research results on high-altitude, long-distance, cross-regional and complex transmission lines. Up to now, there is no complete and reasonable overvoltage improvement method to effectively deal with transmission line insulator flashover accidents. There are problems in the operation of transmission lines. significant safety hazard.

Contents of the invention

The technical problem to be solved by the present invention is how to effectively use the historical data of overhead transmission lines, including flashover data and steady-state data, to propose a method for improving overvoltage, so that the corresponding strategies can be targeted, so as to facilitate the realization of line Differentiated design.

The invention discloses an overvoltage improvement method based on historical data of overhead transmission lines, which is characterized in that:

① Select the flashover frequency section of the transmission line based on historical data, and use electromagnetic transient analysis to determine the Calculate the resistance, inductance, and capacitance of the zero-sequence and positive-sequence lines;

② Calculate the parameters of the power supply, including: line transmission capacity, load side power factor, three-phase and single-phase short-circuit current of the substation, and equivalent positive-sequence impedance and equivalent negative-sequence impedance of the substation;

③ If there are high-voltage shunt reactors installed at the first and last ends of the line, then obtain the parameters of the shunt reactor, including: rated voltage, rated capacity, and compensation during operation;

④ Obtain circuit breaker parameters, including: circuit breaker closing resistance, access time, upper limit of closing three-phase non-synchronous time, and opening three-phase non-synchronous time upper limit;

⑤ Obtain the arrester parameters in the line;

⑥ Calculate the power frequency steady-state voltage reference value, power frequency overvoltage reference value, and operating overvoltage reference value;

⑦ Based on historical data, calculate the steady-state phase-to-ground voltage and steady-state phase-to-phase voltage when the line is in normal steady-state operation, the first and last sections of the transmission line are in normal operation, and calculate the phase-to-ground voltage distribution along the line and the phase-to-phase voltage of the line distributed along the line;

⑧ On the basis of completing the above steps, simulate and calculate power frequency overvoltage, operating overvoltage, and lightning overvoltage;

⑨ According to the calculation results of the above steps, the staff implement appropriate overvoltage improvement strategies.

Detailed ways

The invention discloses an overvoltage improvement method based on historical data of overhead transmission lines, which is characterized in that:

① Select the flashover frequency section of the transmission line based on historical data, and use electromagnetic transient analysis to determine the Calculate the resistance, inductance, and capacitance of the zero-sequence and positive-sequence lines;

② Calculate the parameters of the power supply, including: line transmission capacity, load side power factor, three-phase and single-phase short-circuit current of the substation, and equivalent positive-sequence impedance and equivalent negative-sequence impedance of the substation;

③ If there are high-voltage shunt reactors installed at the first and last ends of the line, then obtain the parameters of the shunt reactor, including: rated voltage, rated capacity, and compensation during operation;

④ Obtain circuit breaker parameters, including: circuit breaker closing resistance, access time, upper limit of closing three-phase non-synchronous time, and opening three-phase non-synchronous time upper limit;

⑤ Obtain the arrester parameters in the line;

⑥ Calculate the power frequency steady-state voltage reference value, power frequency overvoltage reference value, and operating overvoltage reference value;

⑦ Based on historical data, calculate the steady-state phase-to-ground voltage and steady-state phase-to-phase voltage when the line is in normal steady-state operation, the first and last sections of the transmission line are in normal operation, and calculate the phase-to-ground voltage distribution along the line and the phase-to-phase voltage of the line distributed along the line;

⑧ On the basis of completing the above steps, simulate and calculate power frequency overvoltage, operating overvoltage, and lightning overvoltage;

⑨ According to the calculation results of the above steps, the staff implement appropriate overvoltage improvement strategies.

Based on the above-mentioned embodiments, those skilled in the art can fully understand its technical path. The characteristics of this technical solution are: starting from historical data, effectively using historical data, forming a complete system that enables staff to call or execute corresponding processes in a targeted manner. Approaches to voltage improvement strategies. The innovation of the above embodiment lies in the combination of many parameters, distribution along the line and various overvoltage calculations, thus forming an overvoltage improvement method that is different from the prior art and includes as many parameters as possible, which is conducive to the comprehensive consideration of the staff Conventional overvoltage improvement strategies of various natures are targeted to deal with specific situations. This technical solution forms a complete and organic technical solution through the connection of various steps to solve practical problems in the technology, so that it can efficiently solve the safety problem of the line, especially the existing and potential problems in the aspect of overvoltage.

In another embodiment, the overvoltage improvement strategy in the ninth step above includes any one or a combination of the following strategies: changing the configuration parameters of the shunt reactor, changing the configuration parameters of the circuit breaker, changing the creepage distance or the number of insulators, improving the insulator Performance, reduce tower grounding resistance, reduce ground wire protection angle, install line arrester, strengthen ground wire shielding, add bypass ground wire, and add coupling ground wire. It is not difficult for those skilled in the art to find that the purpose of the embodiments herein is to refine alternative overvoltage improvement strategies based on specific calculation results, such as rationally configuring lightning arresters.

In another embodiment, in the above eighth step, the calculation of power frequency overvoltage includes the voltage distribution along the line under the following multiple operation modes: the operation mode of three-phase symmetrical opening of the circuit breaker, the operation of single-phase grounding at the end of the line mode, two-phase grounding operation mode at the end of the line, and two-phase short circuit at the end of the line. As far as this embodiment is concerned, the purpose is to refine the voltage distribution along the line in a lower and more specific operation mode involved in the calculation of the industrial frequency overvoltage. As far as this embodiment is concerned, various factors are comprehensively considered, and by combining historical data of long-term operation, the overvoltage characteristics of the transmission line under specific various operation modes are obtained.

In another embodiment, in the above eighth step, the calculation of the operating overvoltage includes the calculation of the overvoltage in the following multiple operation modes: the calculation of the overvoltage of the three-phase circuit breaker in the operation mode of closing at different times, the calculation of the overvoltage of the single-phase circuit breaker Overvoltage calculation under reclosing operation mode, overvoltage calculation under different phase opening operation mode of three-phase circuit breaker, overvoltage calculation under different phase opening operation mode of three-phase circuit breaker with single-phase grounding. As far as this embodiment is concerned, the purpose is to refine the calculation of the overvoltage involved in the calculation of the operating overvoltage in a lower and more specific operating mode.

In another embodiment, the overvoltage calculation of the above-mentioned three-phase circuit breaker in the different-phase closing operation mode includes: three-phase different-phase closing operation statistical overvoltage calculation, and three-phase different-phase closing operation maximum overvoltage calculation. As far as this embodiment is concerned, the purpose is to refine the overvoltage calculation of the three-phase circuit breaker in different closing operation modes.

In another embodiment, the calculation of the overvoltage in the reclosing operation mode of the single-phase circuit breaker includes: calculation of the maximum statistical overvoltage of 2% single-phase reclosing operation, and calculation of the maximum overvoltage of single-phase reclosing operation. As far as this embodiment is concerned, the purpose is to refine the overvoltage calculation in the single-phase circuit breaker reclosing mode of operation.

In another embodiment, the overvoltage calculation of the above-mentioned three-phase circuit breaker in the different phase opening operation mode includes: 2% calculation of the maximum statistical overvoltage of the three phase different phase opening operation, the maximum overvoltage of the three phase different phase opening operation calculate. As far as this embodiment is concerned, the purpose is to refine the overvoltage calculation of the three-phase circuit breaker in different phase opening operation modes.

In another embodiment, the overvoltage calculation of the above-mentioned three-phase circuit breaker with single-phase grounding in different periods of opening operation mode includes: 2% of the maximum statistical overvoltage of three-phase circuit breakers with ground faults in different periods of opening operation, with grounding Calculation of maximum overvoltage for faulty three-phase circuit breaker opening operation in different phases. As far as this embodiment is concerned, the purpose is to refine the calculation of the overvoltage under the different phase opening operation mode of the three-phase circuit breaker with single-phase grounding.

In another embodiment, in the above eighth step, the calculation of the lightning overvoltage includes: calculating the annual thunderstorm day according to the altitude and historical thunderstorm data of the region. As far as this embodiment is concerned, the purpose is to effectively utilize historical thunderstorm data under certain altitude conditions to improve the calculation of lightning overvoltage. This technical solution is more beneficial for lines with a large range of elevation changes.

In another embodiment, in the above eighth step, the calculation of the lightning overvoltage includes: referring to the above-mentioned annual thunderstorm day, performing lightning counterattack calculation and lightning shielding calculation. As far as this embodiment is concerned, the purpose is to further refine the calculation of lightning overvoltage based on altitude and historical data.

In another embodiment, the tower in the lightning counter calculation adopts a multi-wave impedance model. As far as this embodiment is concerned, the purpose is to specifically select the tower model in the calculation of lightning counterattack.

Among them, the tower model in the calculation of lightning shielding adopts the cat head tower model. As far as this embodiment is concerned, the purpose is to specifically select the tower model in the lightning shielding calculation.

Of course, for the multiple operation modes of the above embodiments, the reason is related to the faults that may be caused by overvoltage in practice, no matter from the perspective of existing theory or practical experience, so the embodiments of the present invention The simulation calculations involved take into account a number of operating modes.

Finally, it should be noted that: the above embodiments are only used to illustrate the present invention rather than limit the technical solutions described in the present invention; therefore although the specification has described the present invention in detail with reference to the above-mentioned various embodiments, those skilled in the art Personnel should understand that the present invention can still be modified or equivalently replaced; and all technical solutions and improvements that do not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims (9)

1. the overvoltage improvement method based on overhead transmission line historical data, is characterized in that:

(1) based on historical data, choose the flashover section of taking place frequently of described transmission line, according to the physical dimension of circuit transposition form, shaft tower, and the wire selected of transmission line and model and the physical dimension thereof of overhead ground wire, utilize electromagnetic transient analysis to come resistance, inductance and the electric capacity of computational scheme zero sequence and positive sequence;

(2) calculate the parameter of power supply, comprising: three-phase and the single-phase short circuit current of circuit transmission capacity, load side power factor, transformer station, and the equivalent positive sequence impedance of transformer station and equivalent negative sequence impedance;

(3) if circuit head and end is provided with high-voltage shunt reactor, obtain so shunt reactor parameter, comprising: rated voltage, rated capacity, and when operation compensativity;

(4) obtain circuit breaker parameters, comprising: breaker closing resistance, turn-on time, combined floodgate three-phase not the same period time upper limit value, and separating brake three-phase not the same period time upper limit value;

(5) obtain the lightning arrester parameter in circuit;

(6) calculate power frequency steady state voltage fiducial value, power-frequency overvoltage fiducial value, and switching overvoltage fiducial value;

(7), based on historical data, during the normal steady operation of computational scheme, transmission line first and last section stable state phase-ground voltage and stable state phase-phase voltage while normally moving, and computational scheme phase-ground voltage is along the line distributes and circuit phase-phase voltage distributes along the line;

(8) complete on the basis of aforementioned each step simulation calculation power-frequency overvoltage, switching overvoltage, and lightning overvoltage;

(9), according to aforementioned each step result of calculation, staff carries out suitable overvoltage and improves strategy;

The overvoltage of above-mentioned the 9th step is improved strategy and is comprised arbitrary or its combination in following strategy: change shunt reactor configuration parameter, change circuit breaker configuration parameter, change insulator creep distance or sheet number, improve Insulators Used, reduce pole tower ground resistance, reduce ground wire shielding angle, install leakage conductor additional, strengthen ground shield, set up bypass ground wire, set up coupling ground wire.

2. method according to claim 1, it is characterized in that: in above-mentioned the 8th step, the calculating of power-frequency overvoltage comprises that the voltage along the line under following multiple operational mode distributes: the operational mode of the operational mode of circuit breaker three-phase symmetrical separating brake, line end generation single-phase earthing, the operational mode of line end generation two phase ground, line end generation two-phase phase fault.

3. method according to claim 1 and 2, it is characterized in that: in above-mentioned the 8th step, the calculating of switching overvoltage comprises that overvoltage under following multiple mode of operation calculates: do not calculate, the overvoltage under single-phase circuit breaker reclosing operation mode is calculated by the overvoltage under the closing operation mode same period for three-phase breaker, three-phase breaker not the overvoltage under the sub-switching operation mode same period calculate, with single-phase earthing three-phase breaker not the overvoltage under the sub-switching operation mode same period calculate.

4. method according to claim 3, is characterized in that: the above-mentioned three-phase breaker not overvoltage under the closing operation mode same period calculates and comprises: three-phase not the same period closing operation statistical overvoltage calculate, three-phase the maximum overvoltage of the closing operation same period calculate.

5. method according to claim 3, is characterized in that: the overvoltage under above-mentioned single-phase circuit breaker reclosing operation mode is calculated and comprised: 2% single-pole reclosing operates maximum statistical overvoltage calculating, single-pole reclosing operates maximum overvoltage and calculates.

6. method according to claim 3, is characterized in that: the above-mentioned three-phase breaker not overvoltage under the sub-switching operation mode same period calculates and comprises: 2% three-phase the maximum statistical overvoltage of the sub-switching operation same period calculate, three-phase the maximum overvoltage of the sub-switching operation same period calculate.

7. method according to claim 3, is characterized in that: above-mentioned with single-phase earthing three-phase breaker not the overvoltage under the sub-switching operation mode same period calculate and comprise: 2% fault three-phase breaker with ground the maximum statistical overvoltage of the sub-switching operation same period calculate, fault three-phase breaker with ground the maximum overvoltage of the sub-switching operation same period calculate.

8. method according to claim 3, is characterized in that: in above-mentioned the 8th step, the calculating of lightning overvoltage comprises: according to the historical thunderstorm data of height above sea level and their location, calculate a year thunderstorm day.

9. method according to claim 8, it is characterized in that: in above-mentioned the 8th step, the calculating of lightning overvoltage comprised: with reference to above-mentioned year thunderstorm day, carrying out back flashover calculating and thunderbolt calculates, and the shaft tower during back flashover calculates adopts multi-wave impedance model, the shaft tower during thunderbolt calculates adopts cat head Tower Model.