阅读说明：本技术 一种变电站电气设备抵御连续雷击的雷电侵入波水平的评估方法 (Assessment method for lightning invasion wave level of substation electrical equipment for resisting continuous lightning stroke ) 是由 宋坤宇 李谦 王增彬 赵晓凤 魏俊涛 于 2020-12-28 设计创作，主要内容包括：本发明提供了一种变电站电气设备抵御连续雷击的雷电侵入波水平的评估方法。本发明基于每次雷击时过电压值和每次设备实际的雷电耐受电压值评估变电站电气设备抵御连续雷击的雷电侵入波水平。本发明的变电站电气设备抵御连续雷击的雷电侵入波水平的评估方法将连续雷击分为第一次及后续回击次数,对每次雷击情况的工况进行独立分析的同时,考虑上次雷击带来的累积效应,计算结果更具有准确性。(The invention provides a method for evaluating the level of lightning invasion waves of electrical equipment of a transformer substation for resisting continuous lightning strokes. The lightning invasion wave level of the electrical equipment of the transformer substation for resisting continuous lightning strokes is evaluated based on the overvoltage value in each lightning stroke and the actual lightning tolerance voltage value of the equipment in each lightning stroke. According to the assessment method for the level of the lightning invasion wave of the electrical equipment of the transformer substation for resisting continuous lightning strokes, the continuous lightning strokes are divided into the first and subsequent attack times, the working condition of each lightning stroke condition is independently analyzed, meanwhile, the cumulative effect caused by the last lightning stroke is considered, and the calculation result is more accurate.)

1. A method for evaluating the level of lightning intrusion waves of electrical equipment of a transformer substation against continuous lightning strikes is characterized by comprising the following steps:

the method comprises the steps of obtaining lightning stroke monitoring data of a power transmission line, and calculating overvoltage, lightning current amplitude and lightning wave impedance of electrical equipment of a transformer substation caused by lightning invasion waves in each lightning stroke based on the lightning stroke monitoring data;

obtaining operation state data of the transformer substation, and calculating rated lightning withstand voltage value U of electrical equipment of the transformer substation based on the operation state data_b；

According to U_n＝α_n·I_n·Z_nCalculating overvoltage U of electrical equipment of the transformer substation caused by lightning intrusion wave in the nth lightning stroke_nWherein, I_nIs the nth lightning current amplitude, Z_nIs the impedance of lightning waves, α_nIs the attenuation coefficient;

will be over-voltage U at the 1 st lightning stroke₁Rated lightning withstand voltage value U of electrical equipment of transformer substation_bMaking a comparison if U₁Less than U_bObtaining that the electrical equipment of the transformer substation can resist overvoltage during the 1 st lightning stroke; if U is₁Greater than U_bWill be over-voltage U in the 2 nd lightning stroke₂Actual lightning withstand voltage value U of electrical equipment of transformer substation_sMaking a comparison if U₂Less than U_sObtaining the overvoltage when the electrical equipment of the transformer substation resists the 2 nd lightning stroke, if U₂Greater than U_sAnd analogizing in turn the overvoltage U at the mth lightning stroke_mActual lightning withstand voltage value U of electrical equipment of transformer substation_xComparing; therein, 2<m<n。

2. A method of assessing a level of lightning intrusion of a substation electrical device against successive lightning strikes according to claim 1, the lightning strike monitoring data comprising: the lightning protection method comprises the steps of the number of a lightning struck power transmission line tower, the lightning strike time, the lightning strike mode and lightning information, wherein the lightning strike mode comprises lightning strike lightning conductor data, lightning strike tower data and lightning strike power transmission conductor data, and the lightning strike information comprises a lightning current amplitude and the number of strike-back times of subsequent continuous lightning strikes.

3. A method of assessing the level of lightning intrusion of a substation electrical device against successive lightning strikes according to claim 1, the operational status data comprising: the operation state data of the transformer substation comprises the voltage grade of the transformer substation, the wiring mode of the transformer substation and the electrical equipment parameters of the transformer substation.

4. Method for assessing the level of lightning intrusion of an electrical substation equipment against successive lightning strikes according to any one of claims 1 to 3, said actual lightning withstand voltage value U_s＝β·U_bWherein the insulation recovery coefficient of the electrical equipment of the beta substation, 0<β<1。

Technical Field

The invention relates to the field of electric power, in particular to a method for evaluating the level of lightning invasion waves of electrical equipment of a transformer substation for resisting continuous lightning strokes.

Background

The transformer substation is an important component of a power system, the transformer substation equipment is expensive, and for most electrical equipment, the insulation of the transformer substation equipment has no self-recovery capability, so that huge economic loss is caused if the transformer substation equipment is damaged due to lightning accidents. The existing standard specification gives many instructive opinions on the electrical performance indexes and the test technical indexes of related electrical equipment in the transformer substation, and many students also carry out a great deal of research work on the electrical characteristics and the failure mechanism of the electrical equipment such as a lightning arrester, a circuit breaker and the like under the lightning impact, so that a great research result is obtained. However, most of the current relevant standards and researches are based on single lightning stroke or multiple lightning strokes separated by a certain time to carry out work, and the performance analysis of electrical equipment under continuous lightning strokes is relatively less.

Continuous lightning stroke is a common phenomenon in nature, and compared with single lightning stroke, the continuous lightning stroke generally refers to continuous lightning strike with a time interval not exceeding 0.1s and a lightning strike position not exceeding 1km, and includes continuous lightning strike or multiple lightning strikes in a short time. The statistical results show that: the continuous lightning strike frequency in the continuous lightning is 2-6 times and accounts for most parts (about 89.53% of all continuous lightning strikes), and the lightning current generally has a negative polarity amplitude range of 5 kA-50 kA.

The damage of the lightning invasion wave of continuous lightning stroke to the circuit breaker and the line arrester on the line side of the transformer substation has become a new problem which is more and more emphasized. When continuous lightning strikes act on a transformer substation or a wire, if the current amplitude of the continuous lightning strikes is large, the lightning impact energy absorbed by the lightning arrester easily exceeds the through-current capacity of the lightning impact energy, and then the electrical energy is overloaded. The circuit breaker also can trip out after the first thunderbolt, when being in the running state of hot reserve, the bus metal oxide arrester can't form good protection to the circuit breaker, if the circuit suffers the thunderbolt again, takes place accidents such as inside breakdown and outer insulation flashover circuit breaker very easily. Therefore, how to evaluate the lightning invasion wave level of the substation electrical equipment for resisting continuous lightning strokes provides guidance for the insulation cooperation of a newly built station and the insulation cooperation optimization of a modified station, and the method has important significance.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides an assessment method for the level of lightning invasion waves of electrical equipment of a transformer substation for resisting continuous lightning strokes. In order to achieve the purpose of the invention, the technical scheme of the invention is as follows.

A method for evaluating the level of lightning intrusion waves of electrical equipment of a transformer substation against continuous lightning strikes comprises the following steps:

the method comprises the steps of obtaining lightning stroke monitoring data of a power transmission line, and calculating overvoltage, lightning current amplitude and lightning wave impedance of electrical equipment of a transformer substation caused by lightning invasion waves in each lightning stroke based on the lightning stroke monitoring data;

acquiring running state data of the transformer substation, and calculating a rated lightning withstand voltage value Ub of electrical equipment of the transformer substation based on the running state data;

according to U_n＝α_n·I_n·Z_nCalculating overvoltage U of electrical equipment of the transformer substation caused by lightning intrusion wave in the nth lightning stroke_nWherein, I_nIs the nth lightning current amplitude, Z_nIs the impedance of lightning waves, α_nIs the attenuation coefficient;

will be over-voltage U at the 1 st lightning stroke₁Rated lightning withstand voltage value U of electrical equipment of transformer substation_bMaking a comparison if U₁Less than U_bObtaining that the electrical equipment of the transformer substation can resist overvoltage during the 1 st lightning stroke; if U is₁Greater than U_bWill be over-voltage U in the 2 nd lightning stroke₂Actual lightning withstand voltage value U of electrical equipment of transformer substation_sMaking a comparison if U₂Less than U_sObtaining the overvoltage when the electrical equipment of the transformer substation resists the 2 nd lightning stroke, if U₂Greater than U_sAnd analogizing in turn the overvoltage U at the mth lightning stroke_mActual lightning withstand voltage value U of electrical equipment of transformer substation_xComparing; wherein m is more than 2 and less than n;

preferably, the lightning strike monitoring data comprises: the lightning protection method comprises the steps of the number of a lightning struck power transmission line tower, the lightning strike time, the lightning strike mode and lightning information, wherein the lightning strike mode comprises lightning strike lightning conductor data, lightning strike tower data and lightning strike power transmission conductor data, and the lightning strike information comprises a lightning current amplitude and the number of strike-back times of subsequent continuous lightning strikes.

Preferably, the operation state data includes: the operation state data of the transformer substation comprises the voltage grade of the transformer substation, the wiring mode of the transformer substation and the electrical equipment parameters of the transformer substation.

Preferably, the actual lightning withstand voltage value U_s＝β·U_bWherein the insulation recovery coefficient of the electrical equipment of the beta transformer substation is more than 0 and less than 1.

Compared with the prior art, the invention has the beneficial technical effects that:

1. the method provided by the invention considers the continuous lightning stroke working condition, the damage probability of the electrical equipment of the transformer substation is higher under the working condition, and the working condition is rarely considered in the prior art, so that the evaluation of the level of the electrical equipment of the transformer substation for resisting the lightning invasion wave of the continuous lightning stroke is a blank field.

2. The method divides the continuous lightning stroke into the 1 st and subsequent strike-back times, independently analyzes the working condition of each lightning stroke condition, considers the cumulative effect caused by the last lightning stroke, and has more accuracy in the calculation result.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application are clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present application without making any creative effort, shall fall within the protection scope of the present application.

The method for evaluating the level of lightning invasion waves of the electrical equipment of the transformer substation for resisting continuous lightning strokes comprises the following steps:

obtaining operation state data of the transformer substation, and calculating rated lightning withstand voltage value U of electrical equipment of the transformer substation based on the operation state data_b；

According to U_n＝α_n·I_n·Z_nCalculating overvoltage U of electrical equipment of the transformer substation caused by lightning intrusion wave in the nth lightning stroke_nWherein, I_nIs the nth lightning current amplitude, Z_nIs the impedance of lightning waves, α_nIs the attenuation coefficient;

will be over-voltage U at the 1 st lightning stroke₁Rated lightning withstand voltage value U of electrical equipment of transformer substation_bMaking a comparison if U₁Less than U_bObtaining that the electrical equipment of the transformer substation can resist overvoltage during the 1 st lightning stroke; if U is₁Greater than U_bWill be over-voltage U in the 2 nd lightning stroke₂Actual lightning withstand voltage value U of electrical equipment of transformer substation_sMaking a comparison if U₂Less than U_sObtaining the overvoltage when the electrical equipment of the transformer substation resists the 2 nd lightning stroke, if U₂Greater than U_sAnd analogizing in turn the overvoltage U at the mth lightning stroke_mActual lightning withstand voltage value U of electrical equipment of transformer substation_xComparing; wherein m is more than 2 and less than n;

the actual lightning withstand voltage value U_s＝β·U_bWherein the insulation recovery coefficient of the electrical equipment of the beta transformer substation is more than 0 and less than 1. For example, β is 0.8.

Specifically, the method comprises the following steps: firstly, acquiring lightning stroke monitoring data and lightning positioning system monitoring data of an actually measured power transmission line body, and analyzing to obtain the number of a tower, the lightning stroke time (accurate to millisecond level), the lightning stroke mode (including lightning stroke lightning conductor data, lightning stroke tower data and lightning stroke power transmission conductor data) and lightning information (including lightning current amplitude, the number of return strokes of subsequent continuous lightning strokes and the like) of a certain address within the range of 1km in diameter.

And secondly, acquiring relevant data of the running state of the transformer substation to be calculated, wherein the relevant data comprises the voltage grade of the transformer substation, the wiring mode of the transformer substation, the parameters of electrical equipment of the transformer substation, the real-time running mode, the configuration condition of a lightning arrester of the transformer substation, the electrical distance of the electrical equipment of the transformer substation and the like.

Thirdly, calculating the overvoltage of the electrical equipment of the transformer substation caused by the lightning invasion wave of the continuous lightning stroke, and setting the 1 st lightning current amplitude of the continuous lightning stroke as I₀A, lightning wave impedance is Z₀Omega, the lightning intrusion wave voltage U of the lightning strike point_T＝I₀·Z₀(ii) a Considering the effects of lightning current shunting effect, transmission attenuation effect of a power transmission line, voltage limitation of a lightning arrester and the like after the tower is struck by lightning in the 1 st lightning stroke, the attenuation coefficient alpha is set₀If the overvoltage of the circuit breaker, the CT and other equipment in the power station is U when the 1 st lightning stroke occurs₁＝α₀·I₀·Z₀。

2 nd lightning current of continuous lightning strikeAmplitude of I₁A, lightning wave impedance is Z₁Omega, the lightning intrusion wave voltage UT at the lightning strike point is I₁·Z₁(ii) a The method includes the steps of considering the effects of lightning current shunting effect, transmission attenuation effect of a power transmission line, voltage limitation of a lightning arrester and the like after lightning strikes on a tower in the 2 nd lightning strike, considering relay protection action possibly caused in the 1 st lightning strike, enabling part of circuit breakers to be in an off state, changing the operation mode of a transformer substation, forming total reflection lifting overvoltage amplitude at the circuit breakers by lightning invasion waves, comprehensively considering gain and attenuation conditions, and setting a coefficient alpha₁And the overvoltage of the circuit breaker, the CT and other equipment in the power station is U when the 2 nd lightning stroke is changed₂＝α₁·I₁·Z₁. In a similar way, the 3 rd and/or nth lightning stroke overvoltage values U of the circuit breaker and the CT can be calculated₃，......U_n。

Fourthly, evaluating the lightning invasion level of the electrical equipment of the transformer substation for resisting continuous lightning strokes, wherein the overvoltage U is over-voltage at the 1 st lightning stroke₁Lightning withstand voltage U corresponding to rated equipment_bMaking a comparison if U₁Less than U_bAnd considering that the equipment can resist overvoltage at the 1 st lightning stroke, otherwise, the equipment cannot resist. For overvoltage U in 2 nd lightning stroke₂Considering that the equipment is insulated and pressure-bearing during the 1 st lightning stroke and is not completely recovered, the actual lightning withstand voltage value Us of the equipment is greatly lower than the rated lightning withstand voltage value U_bThen U is_b2Should correspond to the actual lightning withstand voltage value U of the equipment_sMaking a comparison if U_b2Less than U_sAnd considering that the equipment can resist overvoltage at the 1 st lightning stroke, otherwise, the equipment cannot resist. Similarly, the level of the intrusion wave can be calculated from the 3 rd strike to the nth strike. If each lightning stroke can be borne, the electrical equipment of the transformer substation can resist the lightning invasion waves of the continuous lightning stroke, otherwise, the electrical equipment of the transformer substation cannot bear the lightning invasion waves.

The above-mentioned embodiments are only specific embodiments of the present application, and are used for illustrating the technical solutions of the present application, but not limiting the same, and the scope of the present application is not limited thereto, and although the present application is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: any person skilled in the art can modify or easily conceive the technical solutions described in the foregoing embodiments or equivalent substitutes for some technical features within the technical scope disclosed in the present application; such modifications, changes or substitutions do not depart from the spirit and scope of the present disclosure, which should be construed in light of the above teachings. Are intended to be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.