CN107834527B

CN107834527B - Optimal control method and device for power fluctuation overvoltage of half-wavelength power transmission line

Info

Publication number: CN107834527B
Application number: CN201711048811.9A
Authority: CN
Inventors: 张媛媛; 王平; 王毅; 班连庚; 项祖涛; 韩彬; 宋瑞华; 郑彬; 杨大业; 宋修友; 张翼
Original assignee: State Grid Corp of China SGCC; Beijing Jiaotong University; China Electric Power Research Institute Co Ltd CEPRI; Electric Power Research Institute of State Grid Jiangsu Electric Power Co Ltd
Current assignee: State Grid Corp of China SGCC; Beijing Jiaotong University; China Electric Power Research Institute Co Ltd CEPRI; Electric Power Research Institute of State Grid Jiangsu Electric Power Co Ltd
Priority date: 2017-10-31
Filing date: 2017-10-31
Publication date: 2022-04-29
Anticipated expiration: 2037-10-31
Also published as: CN107834527A

Abstract

The invention provides an optimal control method and device for half-wavelength power transmission line power fluctuation overvoltage, which define the half-wavelength power transmission line power fluctuation overvoltage for the first time, determine the characteristics of the power fluctuation overvoltage, and finally realize the optimal control of the half-wavelength power transmission line power fluctuation overvoltage through an auxiliary control strategy, an arrester uniform configuration strategy and a differentiation configuration strategy. The problem of power fluctuation overvoltage of the half-wavelength power transmission system can be effectively solved, and the safe operation of the half-wavelength power transmission system can be ensured. The auxiliary control strategy of the invention can shorten the duration time of the power fluctuation overvoltage and reduce the amplitude of the power fluctuation overvoltage, thereby reducing the absorption energy of the lightning arresters along the half-wavelength power transmission line, reducing the configuration number of the lightning arresters along the half-wavelength power transmission line, optimizing the configuration of the lightning arresters and reducing the configuration cost of the lightning arresters.

Description

Optimal control method and device for power fluctuation overvoltage of half-wavelength power transmission line

Technical Field

The invention relates to the technical field of power systems, in particular to an optimal control method and device for half-wavelength power transmission line power fluctuation overvoltage.

Background

The half-wavelength power transmission technology (HWACT) refers to a three-phase alternating current power transmission technology with the power frequency half-wavelength close to the power frequency half-wavelength, namely, the ultra-long distance of about 3000km (50Hz) or about 2600km (60Hz), and has the advantages of full-line reactive power self-balancing, no need of installing reactive power compensation equipment and no need of arranging an intermediate switch station. The power transmission capacity is strong, the economy and the reliability are good, and the long-distance synchronous networking can be realized. With the push of the global energy internet, half-wave power transmission is widely concerned as a scheme suitable for large-scale power intercontinental transmission.

However, engineering application of half-wavelength power transmission is also urgently needed to solve some technical problems such as safety and stability control, overvoltage and secondary current suppression, relay protection configuration and the like, wherein the overvoltage suppression is one of the key problems restricting the half-wavelength power transmission application. Due to the special circuit structure of the half-wavelength power transmission line, the overvoltage characteristics of the half-wavelength power transmission line are greatly different from those of the conventional power transmission line. Under the fault conditions of single-phase grounding, two-phase-to-ground short circuit, three-phase grounding short circuit, interphase short circuit and the like, the half-wavelength characteristic of the half-wavelength power transmission line is damaged, the transient overvoltage problem excited by a fault phase and an adjacent sound phase is extremely prominent under the action of a capacitance-rise effect and parameter resonance, and a serious fault point can reach multiple times, so that the half-wavelength power transmission line is the key point for suppressing the overvoltage of the half-wavelength power transmission line.

The half-wavelength power transmission line is connected with a lightning arrester, and the half-wavelength power transmission line is connected with a half-wavelength power transmission line through the lightning arrester. On the other hand, under the condition of a fault in the half-wavelength transmission line area, power fluctuation with a higher amplitude value may occur on the half-wavelength transmission line, so that the transient stability limit and the transmission capacity of the half-wavelength alternating-current transmission system are reduced.

Disclosure of Invention

In order to overcome the defect that a half-wavelength power transmission line cannot safely operate due to overvoltage caused by fault in the prior art, the invention provides an optimal control method and device for the power fluctuation overvoltage of the half-wavelength power transmission line And if the duration of the power fluctuation overvoltage and the maximum absorption energy of the arrester meet the power fluctuation limiting requirement at the same time, optimizing the differential configuration strategy, otherwise, correcting the differential configuration strategy, and realizing the optimal control of the power fluctuation overvoltage of the half-wavelength power transmission line.

In order to achieve the purpose of the invention, the invention adopts the following technical scheme:

on one hand, the invention provides an optimal control method for half-wavelength power transmission line power fluctuation overvoltage, which comprises the following steps:

determining the maximum absorption energy of the lightning arrester under a preset auxiliary control strategy and a preset uniform configuration strategy of the half-wavelength power transmission line;

determining a differential configuration strategy of the arrester along the half-wavelength power transmission line according to the maximum absorption energy of the arrester under the auxiliary control strategy and the uniform configuration strategy, and determining the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the arrester of the half-wavelength power transmission line under the auxiliary control strategy and the differential configuration strategy;

judging whether the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the lightning arrester of the half-wavelength power transmission line under the auxiliary control strategy and the differential configuration strategy simultaneously meet the power fluctuation limiting requirement, optimizing the differential configuration strategy if the power fluctuation overvoltage and the power fluctuation overvoltage simultaneously meet the power fluctuation limiting requirement, and correcting the differential configuration strategy if the power fluctuation overvoltage and the maximum absorption energy of the lightning arrester simultaneously meet the power fluctuation limiting requirement;

the secondary control strategy comprises:

after the half-wavelength power transmission line has a single-phase earth fault, cutting transmission power at a transmission end after a first time interval; and after the single-phase earth fault is cleared, the transmission end power transmission is put into the power transmission system again after a second time interval.

The power fluctuation overvoltage of the half-wavelength power transmission line comprises overvoltage which occurs on the half-wavelength power transmission line when power fluctuation generated under the condition that the half-wavelength power transmission line has a fault exceeds natural power;

the amplitude of the power fluctuation overvoltage is proportional to the ratio of the power fluctuation to the natural power of the half-wavelength power transmission line;

the duration of the power fluctuation overvoltage is consistent with the power fluctuation time of the half-wavelength power transmission line;

if the fault is a single-phase instantaneous earth fault, the fault process of the single-phase instantaneous earth fault comprises a fault period process, a reclosing process and a swinging process.

The uniform configuration strategy is determined according to the following process:

the half-wavelength transmission line is evenly divided into a plurality of line units in a fixed length, and the same groups of lightning arresters are arranged at the end points of each line unit.

The maximum absorption energy of the lightning arrester under the auxiliary control strategy and the uniform configuration strategy is determined according to the following process:

and under the condition of the maximum power transmission capacity of the half-wavelength power transmission line, determining the maximum absorption energy of the lightning arrester under an auxiliary control strategy and a uniform configuration strategy through an electromagnetic transient simulation model of the half-wavelength power transmission system.

The differential configuration strategy for determining the arrester along the half-wavelength power transmission line according to the maximum absorption energy of the arrester under the auxiliary control strategy and the uniform configuration strategy comprises the following steps:

the lightning arresters are arranged at the tail end points and the interior of each line unit on the principle that the maximum absorption energy of a single group of lightning arresters does not exceed 80% of the energy absorption capacity of the lightning arresters, at most two groups of lightning arresters are arranged at each lightning arrester installation position, and the lightning arresters are preferentially arranged at the tail ends of the line units.

The terminal end point and the internally installed arrester of the line unit include:

determining the number of terminal ends of the line units and the number of installations of the internal arresters, comprising:

the terminal end points and the interior of the line unit are provided with m groups of lightning arresters, and the maximum absorption energy of the lightning arresters in the uniform configuration strategy is E_UWhen E is_U＜0.8E_MWhen m is 1; when E is_U≥0.8E_MWhen m is ═ E_U/0.8E_M]，[]Denotes rounding off, where E_MThe ability to withstand the energy absorbed by the arrester;

determining the terminal end point of the line unit and the installation position of the internal arrester, including:

when m is 1, a group of lightning arresters are installed at the tail end of the line unit;

when m is 2, two groups of lightning arresters are installed at the end points of the tail end of the line unit;

when m is more than or equal to 3, two groups of lightning arresters are installed at the end points of the tail end of the line unit, and the rest lightning arresters are arranged in the line unit according to the following modes:

the rest lightning arresters are arranged at positions which are at distances of d, 2d, … and kd from the tail end of the line unit, wherein k is a natural number, d represents the span of the half-wavelength transmission line, and when m is an even number,

when m is an odd number, the number of the carbon atoms,

the determining of the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the lightning arrester of the half-wavelength power transmission line under the auxiliary control strategy and the differential configuration strategy comprises the following steps:

under the condition of the maximum power transmission capacity of the half-wavelength power transmission line, the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the lightning arrester of the half-wavelength power transmission line under an auxiliary control strategy and a differential configuration strategy are determined through an electromagnetic transient simulation model of the half-wavelength power transmission system.

The power fluctuation limit requirements include:

1) the power fluctuation overvoltage of the transformer substation line side is not more than 1.4p.u., and the duration time of the power fluctuation overvoltage of the transformer substation line side is not more than 0.5 s;

2) the amplitude of the power fluctuation overvoltage of the half-wavelength power transmission line and the duration of the power fluctuation overvoltage of the half-wavelength power transmission line meet the temporary overvoltage tolerance of the lightning arrester;

3) the maximum absorption energy of the arrester along the half-wavelength power transmission line meets the tolerance capability of the arrester for absorbing energy.

The optimizing the differential configuration strategy comprises:

the installation position of the lightning arrester on the half-wavelength transmission line is set to be L₁,…,L_h,…,L_HOf, singlyThe maximum absorption energy of the group lightning arrester is E_hH is 1,2, …, H, H represents the total number of installation positions of the lightning arrester on the half-wavelength transmission line;

if E_h＜0.5E_MAnd the terminal of the line unit and the interior share at least two groups of lightning arresters, and the differentiated configuration strategy is updated according to the principle that one group of lightning arresters is reduced from the head end of the line unit to the tail end of the line unit each time, and determining the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the lightning arrester under the updated differential configuration strategy according to the electromagnetic transient simulation model of the half-wavelength power transmission system and in combination with the auxiliary control strategy, judging whether the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the lightning arrester simultaneously meet the power fluctuation limiting requirement under the updated differential configuration strategy, if so, taking the updated differential configuration strategy as a final lightning arrester configuration strategy, and if not, taking the non-updated differential configuration strategy as a final lightning arrester configuration strategy;

if 0.5E_M≤E_h≤E_MAnd the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the arrester of the half-wavelength power transmission line under the auxiliary control strategy and the differential configuration strategy simultaneously meet the power fluctuation limiting requirement, and then the differential configuration strategy is used as a final arrester configuration strategy.

The correcting the differential configuration strategy comprises:

the terminal end point of the line unit and the installation position of the internal lightning arrester are set to be L₁,…,L_i,…,L_NI is 1,2, …, N represents the total number of lightning arrester installation positions in the line unit, L_iIndicates the ith mounting position;

if L is_iClose to L₁Then at L₁And near the head end of the line unit and with L₁And correcting the differential configuration strategy at the position with the distance d according to the principle of adding a group of lightning arresters at each time until the power fluctuation overvoltage and the power of the half-wavelength power transmission line under the auxiliary control strategy and the differential configuration strategyThe duration of the fluctuating overvoltage and the maximum absorption energy of the lightning arrester simultaneously meet the power fluctuation limiting requirement, and the corrected differential configuration strategy is used as a final lightning arrester configuration strategy;

if L is_iClose to L_NThen near the end of the half-wavelength transmission line and L_NAnd (d) correcting the differential configuration strategy at the position with the distance d according to the principle of adding a group of lightning arresters at each time until the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the lightning arresters of the half-wavelength power transmission line under the auxiliary control strategy and the differential configuration strategy simultaneously meet the power fluctuation limiting requirement, and taking the corrected differential configuration strategy as a final lightning arrester configuration strategy.

On the other hand, the invention provides an optimal control device for power fluctuation overvoltage of a half-wavelength power transmission line, which comprises:

the first determining module is used for determining the maximum absorption energy of the lightning arrester under a preset auxiliary control strategy and a preset uniform configuration strategy of the half-wavelength power transmission line;

the second determination module is used for determining a differential configuration strategy of the arrester along the half-wavelength power transmission line according to the maximum absorption energy of the arrester under the auxiliary control strategy and the uniform configuration strategy, and determining the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the arrester of the half-wavelength power transmission line under the auxiliary control strategy and the differential configuration strategy;

the judging module is used for judging whether the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the lightning arrester of the half-wavelength power transmission line under the auxiliary control strategy and the differential configuration strategy simultaneously meet the power fluctuation limiting requirement, if so, the differential configuration strategy is optimized, and otherwise, the differential configuration strategy is corrected;

the secondary control strategy comprises:

The first determining module determines a uniform configuration policy according to the following process:

The first determining module determines the maximum absorption energy of the lightning arrester under an auxiliary control strategy and a uniform configuration strategy according to the following processes:

The second determining module determines the differential configuration strategy of the arrester along the half-wavelength power transmission line according to the maximum absorption energy of the arrester under the auxiliary control strategy and the uniform configuration strategy and the following processes:

The second determining module installs the lightning arrester at the terminal end point and inside the line unit according to the following procedure:

when m is an odd number, the number of the carbon atoms,

the second determining module determines the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the lightning arrester of the half-wavelength power transmission line under the auxiliary control strategy and the differentiation configuration strategy according to the following processes:

The determination module is configured to determine the following power fluctuation limit requirements:

The third determining module optimizes the differential configuration strategy according to the following process:

the installation position of the lightning arrester on the half-wavelength transmission line is set to be L₁,…,L_h,…,L_HThe maximum absorption energy of the single-group lightning arrester is E_hH is 1,2, …, H, H represents the total number of installation positions of the lightning arrester on the half-wavelength transmission line;

if 0.5E_M≤E_h≤E_MAnd the power fluctuation overvoltage of the half-wavelength power transmission line under the auxiliary control strategy and the differential configuration strategy,And (3) the duration of the power fluctuation overvoltage and the maximum absorption energy of the lightning arrester simultaneously meet the power fluctuation limiting requirement, and then the differentiated configuration strategy is used as the final lightning arrester configuration strategy.

The third determining module corrects the differential configuration strategy according to the following process:

if L is_iClose to L₁Then at L₁And near the head end of the line unit and with L₁Correcting the differential configuration strategy at the position with the distance d according to the principle of adding a group of lightning arresters at each time until the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the lightning arresters of the half-wavelength power transmission line under the auxiliary control strategy and the differential configuration strategy simultaneously meet the power fluctuation limiting requirement, and taking the corrected differential configuration strategy as a final lightning arrester configuration strategy;

Compared with the closest prior art, the technical scheme provided by the invention has the following beneficial effects:

the invention provides an optimization control method of half-wavelength transmission line power fluctuation overvoltage, which comprises the steps of firstly determining the preset auxiliary control strategy of the half-wavelength transmission line and the maximum absorption energy of an arrester under the uniform configuration strategy, then determining the differential configuration strategy of the arrester along the half-wavelength transmission line according to the auxiliary control strategy and the maximum absorption energy of the arrester under the uniform configuration strategy, determining the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the arrester of the half-wavelength transmission line under the auxiliary control strategy and the differential configuration strategy, finally judging whether the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the arrester of the half-wavelength transmission line under the auxiliary control strategy and the differential configuration strategy simultaneously meet the power fluctuation limiting requirement, and optimizing the differential configuration strategy if the requirements are met simultaneously, otherwise, correcting the differential configuration strategy to realize the optimal control of the power fluctuation overvoltage of the half-wavelength power transmission line;

the invention provides an optimization control device of half-wavelength power transmission line power fluctuation overvoltage, which comprises a first determining module, a second determining module and a judging module, wherein the first determining module is used for determining the preset maximum absorption energy of an arrester under an auxiliary control strategy and a uniform configuration strategy of the half-wavelength power transmission line;

the optimization control method of the half-wavelength power transmission line power fluctuation overvoltage provided by the invention defines the half-wavelength power transmission line power fluctuation overvoltage for the first time, determines the power fluctuation overvoltage comprising the characteristics that the amplitude of the power fluctuation overvoltage is in direct proportion to the ratio of the power fluctuation to the natural power of the half-wavelength power transmission line and the duration of the power fluctuation overvoltage is consistent with the power fluctuation time of the half-wavelength power transmission line, and provides a basis for the research of the half-wavelength power transmission line;

the power fluctuation limiting requirements in the optimized control method of the half-wavelength power transmission line power fluctuation overvoltage provided by the invention comprise that the power fluctuation overvoltage at the side of the transformer substation line is not more than 1.4p.u., the duration time of the power fluctuation overvoltage at the side of the transformer substation line is not more than 0.5s, the power fluctuation overvoltage amplitude of the half-wavelength power transmission line and the duration time of the power fluctuation overvoltage of the half-wavelength power transmission line both meet the temporary overvoltage tolerance performance of the lightning arrester, and the maximum absorption energy of the lightning arrester along the half-wavelength power transmission line meets the absorption energy tolerance capability of the lightning arrester, so that a judgment basis is provided for the optimized control of the power fluctuation overvoltage;

the optimal control method for the power fluctuation overvoltage of the half-wavelength power transmission line can effectively solve the problem of the power fluctuation overvoltage of the half-wavelength power transmission system, can ensure the safe operation of the half-wavelength power transmission system, and provides a basis and foundation for the suppression of the power fluctuation overvoltage of the half-wavelength power transmission line;

the optimization control method for the half-wavelength power transmission line power fluctuation overvoltage solves the technical problem of novel overvoltage (namely the power fluctuation overvoltage of the half-wavelength power transmission line) faced by the half-wavelength power transmission technology, and provides powerful technical support for the implementation of the half-wavelength alternating current power transmission technology test engineering;

the auxiliary control strategy in the method for optimizing and controlling the power fluctuation overvoltage of the half-wavelength power transmission line can shorten the duration time of the power fluctuation overvoltage and reduce the amplitude of the power fluctuation overvoltage, so that the absorption energy of the lightning arresters along the half-wavelength power transmission line is reduced, the number of the lightning arresters along the half-wavelength power transmission line is reduced, the configuration of the lightning arresters is optimized, and the configuration cost of the lightning arresters is reduced.

Drawings

Fig. 1 is a flowchart of an optimization control method for half-wavelength power transmission line power fluctuation overvoltage in embodiment 1 of the present invention;

fig. 2 is a schematic diagram of a timing sequence and a process of a single-phase ground transient fault occurring in a half-wavelength power transmission line in embodiment 1 of the present invention;

fig. 3 is a schematic wiring diagram of a half-wavelength power transmission system in embodiment 2 of the present invention;

FIG. 4 is a power waveform diagram of three phases at the beginning of a healthy phase in a single-phase instantaneous ground fault process of an extra-high voltage half-wavelength transmission line in embodiment 2 of the present invention;

fig. 5 is a schematic diagram of power fluctuation overvoltage distribution characteristics of an extra-high voltage transmission half-wavelength power transmission line in a single-phase instantaneous ground fault process in embodiment 2 of the present invention;

fig. 6 is a waveform diagram of power fluctuation overvoltage at three stages in the middle of a healthy full-phase line of an extra-high voltage transmission half-wavelength power transmission line in the single-phase instantaneous ground fault process in embodiment 2 of the present invention;

FIG. 7 is a schematic diagram of the maximum absorbed energy distribution characteristic of the lightning arresters along the line of the extra-high voltage transmission half-wavelength power transmission line under the uniform configuration strategy in embodiment 2 of the invention;

fig. 8 is a schematic diagram of the number of lightning arresters to be configured in the line unit of the extra-high voltage half-transmission wavelength line under the auxiliary control strategy and the differential configuration strategy in embodiment 2 of the present invention;

fig. 9 is a schematic diagram of a configuration strategy of 4 groups of lightning arresters in a 10 th line unit under a differential configuration strategy of an extra-high voltage half-wavelength power transmission line in embodiment 2 of the present invention;

fig. 10 is a schematic diagram of a configuration strategy of 3 groups of lightning arresters of a 12 th line unit under a differential configuration strategy of an extra-high voltage half-wavelength power transmission line in embodiment 2 of the present invention;

fig. 11 is a power fluctuation overvoltage waveform diagram of the extra-high voltage half-wavelength power transmission line under the auxiliary control strategy and the differentiated configuration strategy in embodiment 2 of the present invention;

fig. 12 is a maximum absorbed energy distribution diagram of an extra-high voltage half-wavelength transmission line arrester along the line under an auxiliary control strategy and a differential configuration strategy in embodiment 2 of the present invention;

fig. 13 is a power fluctuation overvoltage waveform diagram of the extra-high voltage half-wavelength power transmission line under the differentiated configuration strategy and the auxiliary control strategy after optimization in embodiment 2 of the present invention;

fig. 14 is a diagram of a maximum absorption energy distribution of the lightning arresters along the extra-high voltage half-wavelength power transmission line under the differentiated configuration strategy and the auxiliary control strategy after optimization in embodiment 2 of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

Example 1

The embodiment 1 of the invention provides an optimal control method for half-wavelength power transmission line power fluctuation overvoltage, a specific flow chart is shown in fig. 1, and the specific process is as follows:

s101: determining the maximum absorption energy of the lightning arrester under a preset auxiliary control strategy and a preset uniform configuration strategy of the half-wavelength power transmission line;

s102: determining a differential configuration strategy of the arrester along the half-wavelength power transmission line according to the maximum absorption energy of the arrester under the auxiliary control strategy and the uniform configuration strategy, and determining the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the arrester of the half-wavelength power transmission line under the auxiliary control strategy and the differential configuration strategy;

s103: and judging whether the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the lightning arrester simultaneously meet the power fluctuation limiting requirement under the auxiliary control strategy and the differential configuration strategy, optimizing the differential configuration strategy if the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the lightning arrester simultaneously meet the power fluctuation limiting requirement, and otherwise, correcting the differential configuration strategy.

The power fluctuation overvoltage of the half-wavelength power transmission line comprises overvoltage appearing on the half-wavelength power transmission line when power fluctuation generated under the condition that the half-wavelength power transmission line has a fault exceeds natural power;

the amplitude of the power fluctuation overvoltage is in direct proportion to the ratio of the power fluctuation to the natural power of the half-wavelength power transmission line;

if the fault is a single-phase instantaneous earth fault, the fault process of the single-phase instantaneous earth fault comprises a fault period process, a reclosing process and a swinging process, a specific time sequence and a process of the single-phase instantaneous earth fault of the half-wavelength power transmission line are shown in fig. 2, and t in fig. 2₀Is the time when the half-wavelength power transmission line has single-phase earth fault, t_B1For breaking a faulty phaseTime of trip of the device, t_B2The reclosing time of the fault phase breaker.

The step S101 specifically includes the following steps:

1. determining the following auxiliary control strategy of the half-wavelength power transmission line:

the half-wavelength transmission line is at t shown in figure 2₀A single-phase earth fault occurs at all times, after a first time interval T_C1(T_C1＜t_B2-t_B1) Cutting off transmission power of a transmitting end; after the single-phase earth fault is cleared, a second time interval T is passed_C2The transmission side transmission power is newly input, and the newly input transmission side transmission power is the same as the transmission side transmission power that was cut out before.

2. Determining the following uniform configuration strategy of the arrester along the half-wavelength power transmission line:

uniformly dividing the half-wavelength power transmission line into a plurality of line units in a fixed length, and installing the same group number of lightning arresters at the end point of each line unit;

3. determining the maximum absorption energy of the lightning arrester under an auxiliary control strategy and a uniform configuration strategy according to the following processes:

The step S102 specifically includes the following steps:

1. determining a differential configuration strategy of the arrester along the half-wavelength power transmission line according to the maximum absorption energy of the arrester under the auxiliary control strategy and the uniform configuration strategy, wherein the specific process comprises the following steps:

the method is characterized in that the maximum absorption energy of a single group of lightning arresters does not exceed 80% of the absorption energy tolerance capacity of the lightning arresters, the maximum two groups of lightning arresters are installed at each lightning arrester installation position, and the lightning arresters are preferentially installed at the tail ends of line units, wherein the specific process of installing the lightning arresters at the tail ends and the interior of the line units is as follows:

1) determining the number of terminal ends of the line units and the number of installations of the internal arresters, comprising:

2) determining the terminal end point of the line unit and the installation position of the internal arrester, including:

when m is an odd number, the number of the carbon atoms,

2. determining the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the lightning arrester of the half-wavelength power transmission line under an auxiliary control strategy and a differential configuration strategy according to the following processes:

The step S103 specifically includes the following steps:

1. the following power fluctuation limit requirements are determined:

4) the maximum absorption energy of the arrester along the half-wavelength power transmission line meets the tolerance capability of the arrester for absorbing energy.

2. Under the condition that the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the lightning arrester of the half-wavelength power transmission line under the auxiliary control strategy and the differential configuration strategy simultaneously meet the power fluctuation limiting requirement, the differential configuration strategy is optimized according to the following processes:

the installation position of the lightning arrester on the half-wavelength transmission line is set to be L₁,…,L_h,…,L_HThe maximum absorption energy of the single-group lightning arrester is E_hH is 1,2, …, H, H represents the total number of installation positions of the lightning arrester on the half-wavelength transmission line; the method is divided into the following two aspects:

1) if E_h＜0.5E_MAnd the terminal of the line unit and the interior share at least two groups of lightning arresters, and the differentiated configuration strategy is updated according to the principle that one group of lightning arresters is reduced from the head end of the line unit to the tail end of the line unit each time, and determining the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the lightning arrester under the updated differential configuration strategy according to the electromagnetic transient simulation model of the half-wavelength power transmission system and in combination with the auxiliary control strategy, and judging whether the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the lightning arrester simultaneously meet the power fluctuation limiting requirement under the updated differential configuration strategy, if so, taking the updated differential configuration strategy as a final lightning arrester configuration strategy, and if not, taking the non-updated differential configuration strategy as a final lightning arrester configuration strategy.The lightning arrester configuration strategy;

2) if 0.5E_M≤E_h≤E_MAnd the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the arrester of the half-wavelength power transmission line under the auxiliary control strategy and the differential configuration strategy simultaneously meet the power fluctuation limiting requirement, and then the differential configuration strategy is used as a final arrester configuration strategy.

3. Under the condition that the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the lightning arrester cannot simultaneously meet the power fluctuation limiting requirement under the auxiliary control strategy and the differential configuration strategy, the differential configuration strategy is corrected according to the following processes:

the terminal end point of the line unit and the installation position of the internal lightning arrester are set to be L₁,…,L_i,…,L_NI is 1,2, …, N represents the total number of lightning arrester installation positions in the line unit, L_iIndicates the ith mounting position; the method is divided into the following two aspects:

1) if L is_iClose to L₁Then at L₁And near the head end of the line unit and with L₁Correcting the differential configuration strategy at the position with the distance d according to the principle of adding a group of lightning arresters at each time until the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the lightning arresters of the half-wavelength power transmission line under the auxiliary control strategy and the differential configuration strategy simultaneously meet the power fluctuation limiting requirement, and taking the corrected differential configuration strategy as a final lightning arrester configuration strategy;

2) if L is_iClose to L_NThen near the end of the half-wavelength transmission line and L_NAnd (d) correcting the differential configuration strategy at the position with the distance d according to the principle of adding a group of lightning arresters at each time until the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the lightning arresters of the half-wavelength power transmission line under the auxiliary control strategy and the differential configuration strategy simultaneously meet the power fluctuation limiting requirement, and taking the corrected differential configuration strategy as a final lightning arrester configuration strategy.

Based on the same inventive concept, the embodiment of the invention also provides an optimal control device for the power fluctuation overvoltage of the half-wavelength power transmission line, the principle of solving the problems of the devices is similar to the optimal control method for the power fluctuation overvoltage of the half-wavelength power transmission line, the optimal control device for the power fluctuation overvoltage of the half-wavelength power transmission line provided by the embodiment of the invention comprises a first determining module, a second determining module and a judging module, and the functions of the modules are respectively explained in detail below:

the second determining module is used for determining a differential configuration strategy of the arrester along the half-wavelength power transmission line according to the maximum absorption energy of the arrester under the auxiliary control strategy and the uniform configuration strategy, and determining the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the arrester of the half-wavelength power transmission line under the auxiliary control strategy and the differential configuration strategy;

the judging module is used for judging whether the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the lightning arrester of the half-wavelength power transmission line under the auxiliary control strategy and the differential configuration strategy simultaneously meet the power fluctuation limiting requirement, if so, the differential configuration strategy is optimized, otherwise, the differential configuration strategy is corrected;

the power fluctuation overvoltage of the half-wavelength power transmission line comprises the overvoltage appearing on the half-wavelength power transmission line when the power fluctuation generated under the condition that the half-wavelength power transmission line has a fault exceeds natural power;

if the fault is a single-phase instantaneous earth fault, the fault process of the single-phase instantaneous earth fault comprises a fault periodThe interval process, reclosing process and swing process are shown in FIG. 2, and t in FIG. 2 is a time sequence and a process of a single-phase grounding instantaneous fault of a half-wavelength transmission line₀Is the time when the half-wavelength power transmission line has single-phase earth fault, t_B1The time of tripping of the fault phase breaker; t is t_B2The reclosing time of the fault phase breaker.

In one aspect, the auxiliary control strategy determined by the first determining module is as follows:

On the other hand, the uniform configuration policy determined by the first determining module is as follows:

In another aspect, the first determining module determines the maximum absorption energy of the lightning arrester under the auxiliary control strategy and the uniform configuration strategy according to the following procedures:

On one hand, the second determining module determines the differential configuration strategy of the arrester along the half-wavelength power transmission line according to the maximum absorption energy of the arrester under the auxiliary control strategy and the uniform configuration strategy and according to the following processes:

On the other hand, the above-mentioned second determination module installs the lightning arrester at the terminal end point and inside of the line unit according to the following procedure:

when m is an odd number, the number of the carbon atoms,

on the other hand, the second determining module determines the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the lightning arrester of the half-wavelength power transmission line under the auxiliary control strategy and the differentiation configuration strategy according to the following processes:

In one aspect, the determination module determines the following power fluctuation limit requirements:

On the other hand, under the condition that the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the lightning arrester of the half-wavelength power transmission line under the auxiliary control strategy and the differential configuration strategy simultaneously meet the power fluctuation limiting requirement, the third determining module optimizes the differential configuration strategy according to the following processes:

the installation position of the lightning arrester on the half-wavelength transmission line is set to be L₁,…,L_h,…,L_HThe maximum absorption energy of the single-group lightning arrester is E_hH is 1,2, …, H, H represents the total number of installation positions of the lightning arrester on the half-wavelength transmission line; the following two cases are distinguished:

1) if E_h＜0.5E_MAnd the end point and the interior of the line unit are provided with at least two groups of lightning arresters, the differential configuration strategy is updated according to the principle that one group of lightning arresters is reduced from the head end of the line unit to the tail end of the line unit each time, the power fluctuation overvoltage, the duration time of the power fluctuation overvoltage and the maximum absorption energy of the lightning arresters of the half-wavelength power transmission line under the updated differential configuration strategy are determined by combining an auxiliary control strategy according to an electromagnetic transient simulation model of the half-wavelength power transmission system, and the power fluctuation overvoltage, the duration time of the power fluctuation overvoltage and the maximum absorption energy of the lightning arresters of the half-wavelength power transmission line under the updated differential configuration strategy are judged, and the power of the half-wavelength power transmission line under the updated differential configuration strategy is judgedWhether the rate fluctuation overvoltage, the duration time of the power fluctuation overvoltage and the maximum absorption energy of the lightning arrester meet the power fluctuation limiting requirement or not simultaneously, if so, taking the updated differentiated configuration strategy as a final lightning arrester configuration strategy, and if not, taking the un-updated differentiated configuration strategy as a final lightning arrester configuration strategy;

On the other hand, under the condition that the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the lightning arrester cannot simultaneously meet the power fluctuation limiting requirement under the auxiliary control strategy and the differential configuration strategy, the third determining module corrects the differential configuration strategy according to the following processes:

the terminal end point of the line unit and the installation position of the internal lightning arrester are set to be L₁,…,L_i,…,L_NI is 1,2, …, N represents the total number of lightning arrester installation positions in the line unit, L_iIndicates the ith mounting position; the following two cases are distinguished:

2) if L is_iClose to L_NThen near the end of the half-wavelength transmission line and L_NAnd (3) correcting the differential configuration strategy at the position with the distance d according to the principle of adding one group of lightning arresters every timeAnd simultaneously meeting the power fluctuation limiting requirement by the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the lightning arrester of the half-wavelength power transmission line under the auxiliary control strategy and the differential configuration strategy, and taking the corrected differential configuration strategy as a final lightning arrester configuration strategy.

Example 2

The embodiment 2 of the present invention takes a single-circuit extra-high voltage half-wavelength power transmission system as an example, and explains the method for optimally controlling the power fluctuation overvoltage of a half-wavelength alternating current power transmission line:

the wiring schematic diagram of a certain point-to-grid ultra-high voltage half-wavelength power transmission system is shown in fig. 3, wherein a transmitting end of the system adopts 10 600MW units to boost the voltage to 1000kV, and the transmitting end is connected to a receiving end system through a 3000km line erected in a single loop, and the receiving end is directly connected to a 1000kV power grid. The receiving end adopts a single machine infinite system, and the short-circuit capacity of the half-wavelength transmission line is 40kA before the half-wavelength transmission line is connected. The maximum transmission power is designed according to 5000 MW. The approximate sequence parameters of the 1000kV single-circuit line are shown in table 1:

TABLE 1

Neglecting the line loss, the wave impedance Z of the extra-high voltage line can be obtained according to the table 1_c245.8 Ω, natural power 4485MW (1p.u.) at 1050kV, wavelength 5898km, exact half wavelength 2949 km. In the research, the length of a half-wavelength transmission line is set to be 3000km, and the number of the half-wavelength transmission line is 30, and each half-wavelength transmission line is 100 km. The rated voltage of the lightning arrester along the extra-high voltage half-wave long power transmission system is 876kV, and the energy absorption tolerance E of the lightning arrester_MIs 42 MJ.

The method for controlling the power fluctuation overvoltage of the half-wavelength power transmission system provided by the embodiment 2 of the invention comprises the following specific processes:

step 1: determining the maximum absorption energy of the lightning arrester under a preset auxiliary control strategy and a uniform configuration strategy of the half-wavelength power transmission line:

step 1-1: when the extra-high voltage half-wavelength transmission line has a single-phase transient fault, high-amplitude power fluctuation exists on the half-wavelength transmission line, as shown in fig. 4. When the power fluctuation exceeds the natural power, overvoltage occurs along the half-wavelength power transmission line, and the overvoltage extreme point along the line is located in the middle section of the line, as shown in fig. 5. The overvoltage at the position of the extreme point is shown in fig. 6, the amplitude (per unit value) of the overvoltage is proportional to the ratio of the power fluctuation to the natural power, and the overvoltage duration is consistent with the time of the power fluctuation. The overvoltage is the power fluctuation overvoltage defined by the invention. The power fluctuation overvoltage is characterized by the category of temporary overvoltage, high amplitude, long duration and wide coverage area along the line.

Step 1-2: the single-phase instantaneous grounding fault is used as the power fluctuation overvoltage research fault condition of the half-wavelength power transmission line, and the single-phase instantaneous grounding process is divided into three stages, namely a fault process, a reclosing period and a system swinging process after reclosing is successful. Moment t of single-phase earth fault of half-wavelength power transmission line₀4s, and the tripping time of the fault phase breaker is t_B1Is 4.125 s; reclosing time t of fault phase circuit breaker_B2It was 5.025 s.

Step 1-3: determining an auxiliary control strategy of the half-wavelength power transmission line: determining maximum transmission power S which can be cut off at one time by a transmission end power supply of the extra-high voltage half-wavelength power transmission system under the condition of single-phase instantaneous earth fault of the extra-high voltage half-wavelength power transmission system_C600MW, a unit rated power. Under the condition that the half-wavelength power transmission line has single-phase instantaneous earth fault, T is carried out after the fault_C(T_C200ms), namely at the time of 4.2s, the power supply of the transmitting terminal of the half-wavelength power transmission line cuts 1 set T with 600MW_C＜t_B2-t_B1900 ms. And at the moment of 6.5s, the power supply of the transmitting terminal of the half-wavelength power transmission line is put into the 600MW unit again.

Step 1-4: the extra-high voltage half-wavelength transmission line is evenly divided into 30 line units with the fixed length of 100km, and 2 groups of lightning arresters are arranged at the end point of each line unit.

Step 1-5: the maximum absorption energy of the arrester under the auxiliary control strategy and the uniform configuration strategy of the half-wavelength power transmission line is determined according to the following processes: under the condition that the maximum power transmission capacity of the extra-high voltage half-wavelength power transmission line is 5000MW, the maximum absorption energy of the lightning arrester in the single-phase instantaneous ground fault process is shown in fig. 7 under the auxiliary control strategy and the uniform configuration strategy of the half-wavelength power transmission line determined by the electromagnetic transient simulation model of the half-wavelength power transmission system.

Step 2: determining a differential configuration strategy of the arrester along the half-wavelength power transmission line according to the maximum absorption energy of the arrester under the auxiliary control strategy and the uniform configuration strategy of the half-wavelength power transmission line, and determining the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the arrester of the half-wavelength power transmission line in the auxiliary control strategy and the differential configuration strategy:

step 2-1: the differential configuration strategy for determining the lightning arresters along the extra-high voltage half-wavelength power transmission line according to the maximum absorption energy of the lightning arresters under the auxiliary control strategy and the uniform configuration strategy of the half-wavelength power transmission line comprises the following steps: the lightning arresters are arranged at the end points of each line unit and in the line units on the basis that the maximum absorption energy of a single group of lightning arresters does not exceed 80 percent of the energy absorption capacity of the lightning arresters and the maximum two groups of lightning arresters are arranged at the installation position of each lightning arrester. The line unit determines the installation number of the lightning arresters according to the following process:

the terminal end points and the interior of the line unit are provided with m groups of lightning arresters, and the maximum absorption energy of the lower lightning arrester in the uniform configuration strategy is E_UWhen E is_U＜0.8E_MWhen m is 1; when E is_U≥0.8E_MWhen m is ═ E_U/0.8E_M]，[]Denotes rounding off, where E_MAnd the energy absorption endurance capacity of the lightning arrester. Therefore, the number of the lightning arresters required to be configured in each line unit along the extra-high voltage half-wavelength transmission line is obtained, wherein the number of the lightning arresters comprises the tail end point and the interior of the line unit, and as shown in fig. 8, the number of the lightning arresters is 62.

The line unit determines the terminal end point of the line unit and the installation position of the internal arrestor according to the following procedures:

the rest lightning arresters are arranged at positions which are at distances of 400m, 800m, … and k multiplied by 400m from the tail end point of the line unit, wherein k is a natural number, the span of the extra-high voltage half-wavelength transmission line is 400m, and when m is an even number,

when m is an odd number, the number of the carbon atoms,

the arrangement positions of the plural sets of lightning arresters will be described by taking the 10 th line unit (line unit 900km to 1000km from the head end of the line) and the 12 th line unit (line unit 1100km to 1200km from the head end of the line) as examples:

as shown in fig. 8, 4 groups of lightning arresters are required to be configured for the 10 th line unit, 2 groups of lightning arresters are installed at the end points of the line unit, and 2 groups of lightning arresters are required to be installed inside the line. The 2 groups of lightning arresters inside the line are arranged at a distance of 400m from the end points of the line units, as shown in fig. 9.

According to fig. 9, 3 groups of lightning arresters are required to be configured for the 12 th line unit, 2 groups of lightning arresters are installed at the end points of the line unit, and 1 group is required to be installed inside the line. The line interior 1 group of arresters was arranged at a distance of 400m from the end point of the line unit, as shown in fig. 10.

Step 2-2: under the condition that the maximum power transmission capacity of the extra-high voltage half-wavelength power transmission line is 5000MW, determining the power fluctuation overvoltage, the power fluctuation overvoltage duration and the maximum absorption energy of a lightning arrester of the half-wavelength power transmission line under an auxiliary control strategy and a differential configuration strategy through an electromagnetic transient simulation model of a half-wavelength power transmission system: the maximum amplitude of the power fluctuation overvoltage along the line is 1.59pu, and the overvoltage duration of 1.55-1.59 pu is 0.9s, as shown in fig. 11; the maximum absorption energy distribution of the extra-high voltage half-wavelength line arrester (single group) is shown in figure 12.

And step 3: judging whether the power fluctuation overvoltage, the power fluctuation overvoltage duration and the maximum absorption energy of the lightning arrester of the half-wavelength power transmission line under the auxiliary control strategy and the differential configuration strategy simultaneously meet the power fluctuation limiting requirement, optimizing the differential configuration strategy if the power fluctuation overvoltage and the power fluctuation overvoltage duration simultaneously meet the power fluctuation limiting requirement, and otherwise, correcting the differential configuration strategy:

step 3-1: determining the following power fluctuation limiting requirements of the half-wavelength power transmission system:

1) the power fluctuation overvoltage of the ultra-high voltage transformer substation line side is not more than 1.4p.u., and the duration time of the power fluctuation overvoltage of the transformer substation line side is not more than 0.5 s;

2) the power fluctuation overvoltage amplitude of the extra-high voltage half-wavelength power transmission line and the duration of the power fluctuation overvoltage of the half-wavelength power transmission line both meet the temporary overvoltage tolerance performance of the lightning arrester, and are specifically shown in table 2:

TABLE 2

Step 3-2: and optimizing a differentiated configuration strategy:

the installation position of the lightning arrester on the extra-high voltage half-wavelength transmission line is set to be L₁,…,L_h,…,L_H，L_hThe maximum absorption energy of the single group of lightning arresters is E_hAnd H is 1,2, …, H and H represents the total number of the installation positions of the lightning arrester on the half-wavelength transmission line.

According to fig. 12, the arresters of line units 3 and 13 have maximum absorbed energy less than 21MJ (0.5EM), and the ends and the interior share at least two groups of arresters; the maximum absorption energy of the lightning arresters of other line units meets 0.5E_M≤E_h≤E_MAnd the power fluctuation overvoltage duration meet the power fluctuation limiting requirement. Thus updating the difference on the basis of the principle of reducing a group of arresters from the head end of the line unit to the tail end of the line unitAnd configuring the configuration number of the lightning arresters of the 3 rd and 13 th line units in the configuration strategy. And determining the power fluctuation overvoltage, the power fluctuation overvoltage duration and the maximum absorption energy of the lightning arrester of the half-wavelength power transmission line under the updated differential configuration strategy according to an electromagnetic transient simulation model of the half-wavelength power transmission system: the maximum amplitude of the power fluctuation overvoltage along the line is 1.59pu, and the overvoltage duration of 1.55-1.59 pu is 0.9s, as shown in fig. 13; the maximum absorption energy distribution of the extra-high voltage half-wavelength line arrester (single group) is shown in fig. 14. The above results can meet the power fluctuation limitation requirements, so that the updated differentiated configuration strategy is used as the final arrester configuration strategy. 60 groups of lightning arresters are required to be configured on the extra-high voltage half-wavelength transmission line.

For convenience of description, each part of the above-described apparatus is separately described as being functionally divided into various modules or units. Of course, the functionality of the various modules or units may be implemented in the same one or more pieces of software or hardware when implementing the present application.

As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

Finally, it should be noted that: the above embodiments are only intended to illustrate the technical solution of the present invention and not to limit the same, and a person of ordinary skill in the art can make modifications or equivalents to the specific embodiments of the present invention with reference to the above embodiments, and such modifications or equivalents without departing from the spirit and scope of the present invention are within the scope of the claims of the present invention as set forth in the claims.

Claims

1. An optimal control method for half-wavelength power transmission line power fluctuation overvoltage is characterized by comprising the following steps: determining the maximum absorption energy of the lightning arrester under a preset auxiliary control strategy and a preset uniform configuration strategy of the half-wavelength power transmission line;

judging whether the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the lightning arrester of the half-wavelength power transmission line under the auxiliary control strategy and the differential configuration strategy simultaneously meet the power fluctuation limiting requirement, optimizing the differential configuration strategy if the power fluctuation overvoltage and the power fluctuation overvoltage simultaneously meet the power fluctuation limiting requirement, and correcting the differential configuration strategy if the power fluctuation overvoltage and the maximum absorption energy of the lightning arrester simultaneously meet the power fluctuation limiting requirement; the secondary control strategy comprises:

2. The method for optimally controlling the power fluctuation overvoltage of the half-wavelength power transmission line according to claim 1, wherein the power fluctuation overvoltage of the half-wavelength power transmission line comprises the overvoltage which occurs on the half-wavelength power transmission line when the power fluctuation generated under the condition that a fault occurs on the half-wavelength power transmission line exceeds the natural power;

and if the fault is a single-phase instantaneous earth fault, the fault process of the single-phase instantaneous earth fault comprises a fault period process, a reclosing process and a swinging process.

3. The method for optimizing control over power fluctuation overvoltage of half-wavelength power transmission line according to claim 1 or 2, wherein the uniform configuration strategy is determined according to the following process:

4. The optimal control method for the power fluctuation overvoltage of the half-wavelength power transmission line according to the claim 1 or 2, characterized in that the maximum absorption energy of the lightning arrester under the auxiliary control strategy and the uniform configuration strategy is determined according to the following process:

5. The method for optimally controlling the power fluctuation overvoltage of the half-wavelength power transmission line according to the claim 1 or 2, wherein the step of determining the differential configuration strategy of the lightning arresters along the half-wavelength power transmission line according to the maximum absorption energy of the lightning arresters under the auxiliary control strategy and the uniform configuration strategy comprises the following steps:

6. The method of claim 5 for optimizing control of half-wavelength power transmission line power fluctuation overvoltage, wherein the terminal end points of the line units and the internally installed lightning arresters comprise:

when m is an odd number, the number of the carbon atoms,

7. the method for optimally controlling the power fluctuation overvoltage of the half-wavelength power transmission line according to claim 1 or 2, wherein the determining of the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the lightning arrester of the half-wavelength power transmission line under the auxiliary control strategy and the differentiated configuration strategy comprises:

8. The method of claim 1 for optimizing control of half-wavelength power transmission line power fluctuation overvoltage, wherein the power fluctuation limiting requirement comprises:

9. The method for optimizing control over power fluctuation overvoltage of half-wavelength power transmission line according to claim 1,2 or 8, wherein the optimizing the differential configuration strategy comprises:

E_Mthe ability to withstand the energy absorbed by the arrester; if E_h＜0.5E_MAnd the terminal of the line unit and the interior share at least two groups of lightning arresters, and the differentiated configuration strategy is updated according to the principle that one group of lightning arresters is reduced from the head end of the line unit to the tail end of the line unit each time, and determining the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the lightning arrester under the updated differential configuration strategy according to the electromagnetic transient simulation model of the half-wavelength power transmission system and in combination with the auxiliary control strategy, judging whether the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the lightning arrester simultaneously meet the power fluctuation limiting requirement under the updated differential configuration strategy, if so, taking the updated differential configuration strategy as a final lightning arrester configuration strategy, and if not, taking the non-updated differential configuration strategy as a final lightning arrester configuration strategy;

10. The method according to claim 1,2 or 8, wherein the modifying the differential configuration strategy comprises:

11. An optimal control device for half-wavelength transmission line power fluctuation overvoltage is characterized by comprising:

the secondary control strategy comprises:

12. The apparatus of claim 11, wherein the power fluctuation overvoltage of the half-wavelength power transmission line comprises an overvoltage occurring on the half-wavelength power transmission line when a power fluctuation generated in the event of a fault on the half-wavelength power transmission line exceeds a natural power;

13. The device for optimizing and controlling the power fluctuation overvoltage of the half-wavelength power transmission line according to claim 11 or 12, wherein the first determining module determines the uniform configuration strategy according to the following process:

14. The optimal control device for the power fluctuation overvoltage of the half-wavelength power transmission line according to claim 11 or 12, wherein the first determining module determines the maximum absorption energy of the lightning arrester under an auxiliary control strategy and a uniform configuration strategy according to the following procedures:

15. The optimal control device for the power fluctuation overvoltage of the half-wavelength power transmission line according to claim 11 or 12, wherein the second determination module determines the differential configuration strategy of the arresters along the half-wavelength power transmission line according to the maximum absorption energy of the arresters under the auxiliary control strategy and the uniform configuration strategy and according to the following process:

16. The apparatus for optimizing control of power fluctuation overvoltage of half wavelength power transmission line according to claim 15, wherein the second determining module installs lightning arresters at the end points and inside the line units according to the following procedure:

the terminal end points and the interior of the line unit are provided with m groups of lightning arresters, and the maximum absorption energy of the lightning arresters in the uniform configuration strategy is E_UWhen E is_U＜0.8E_MWhen m is 1; when E is_U≥0.8E_MWhen m is ═ E_U/0.8E_M]，[]Means for rounding offTaking the whole, wherein E_MThe ability to withstand the energy absorbed by the arrester;

when m is an odd number, the number of the carbon atoms,

17. the optimal control device for the power fluctuation overvoltage of the half-wavelength power transmission line according to claim 11 or 12, wherein the second determination module determines the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the lightning arrester of the half-wavelength power transmission line under the auxiliary control strategy and the differential configuration strategy according to the following procedures:

18. The apparatus of claim 11 wherein the decision module is configured to determine the following power fluctuation limiting requirements:

19. The device for optimizing and controlling the power fluctuation overvoltage of the half-wavelength power transmission line according to claim 11, 12 or 18, wherein the judgment module optimizes the differential configuration strategy according to the following process: the installation position of the lightning arrester on the half-wavelength transmission line is set to be L₁,…,L_h,…,L_HThe maximum absorption energy of the single-group lightning arrester is E_hH is 1,2, …, H, H represents the total number of installation positions of the lightning arrester on the half-wavelength transmission line;

E_Mcapability of absorbing energy for lightning arrester, if E_h＜0.5E_MAnd the terminal of the line unit and the interior share at least two groups of lightning arresters, and the differentiated configuration strategy is updated according to the principle that one group of lightning arresters is reduced from the head end of the line unit to the tail end of the line unit each time, and determining the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the lightning arrester under the updated differential configuration strategy according to the electromagnetic transient simulation model of the half-wavelength power transmission system and in combination with the auxiliary control strategy, judging whether the power fluctuation overvoltage, the duration of the power fluctuation overvoltage and the maximum absorption energy of the lightning arrester simultaneously meet the power fluctuation limiting requirement under the updated differential configuration strategy, if so, taking the updated differential configuration strategy as a final lightning arrester configuration strategy, and if not, taking the non-updated differential configuration strategy as a final lightning arrester configuration strategy;

if 0.5E_M≤E_h≤E_MAnd assist in controllingAnd (3) under the strategy and the differential configuration strategy, the power fluctuation overvoltage of the half-wavelength power transmission line, the duration of the power fluctuation overvoltage and the maximum absorption energy of the lightning arrester simultaneously meet the power fluctuation limiting requirement, and then the differential configuration strategy is used as a final lightning arrester configuration strategy.

20. The device for optimizing and controlling the power fluctuation overvoltage of the half-wavelength power transmission line according to claim 11, 12 or 18, wherein the judgment module corrects the differential configuration strategy according to the following process: the terminal end point of the line unit and the installation position of the internal lightning arrester are set to be L₁,…,L_i,…,L_NI is 1,2, …, N represents the total number of lightning arrester installation positions in the line unit, L_iIndicates the ith mounting position;