CN104362600A - New energy based integrated configuration method for alternating current transmission line unit protection - Google Patents
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Abstract
The invention discloses a new energy based integrated configuration method for alternating current transmission line unit protection. The method mainly includes: performing qualitative judgment on operating conditions of a line by utilizing electrical sampled data collected in each phase on two sides of the line; respectively starting longitudinal impedance of different forms according to a conclusion made by qualitative judgment; when the transmission line makes increment of corresponding current to be measured effectively, starting a corresponding longitudinal impedance algorithm and determining whether internal fault happens to the line or not according to longitudinal impedance results. The integrated configuration method for ultrahigh-voltage alternating current transmission line unit protection can overcome the defects of weak anti-jamming capability, low reliability, poor safety and the like in the prior art, and has the advantages of high anti-jamming capability, high reliability and good safety.
Description
Technical Field
The invention relates to the technical field of relay protection of an extra-high voltage alternating current transmission line of a power system, in particular to a comprehensive configuration method of unit protection of the extra-high voltage alternating current transmission line.
Background
As is well known, in the environment of huge energy consumption in the world at present, a new energy grid-connected technology is an effective new measure widely adopted by domestic and foreign electric power systems to replace traditional power generation, energy conservation and emission reduction, wherein wind power generation occupies the largest quota; however, the existing relay protection technology of the ultra-high voltage alternating current transmission line used for new energy grid connection has the technical problems of narrow adaptive system operation change range, difficulty in sensitive fault discovery and reliable disturbance filtering and coordination, and the like. In view of the requirement of high power supply reliability of the smart power grid, the improvement of the fault discrimination capability of the power transmission line has important economic value and engineering potential, and particularly important research on comprehensive configuration all-weather protection with a fault property identification function and a wide-range adaptive operation mode is important.
At present, the configuration method of the unit protection of the existing alternating current transmission line can be divided into several types, such as current phasor differential protection, direction comparison pilot protection, distance pilot protection, phase differential pilot protection and the like, based on the power frequency full-quantity and power frequency fault components.
The current phasor differential protection mainly utilizes the first current law of kirchhoff and relevant characteristics to realize normal operation and effective identification of faults in a region. However, it is difficult to construct a line model that is beneficial to analysis of protection performance, and there is no reasonable means to assist in setting protection parameters, and the basis for judging non-internal faults is affected by many interference factors during actual operation, so there are many problems, such as load components (mainly aiming at full-scale current differential protection), line distributed capacitance, TA transmission error, TA saturation, clock skew at two ends of the line, etc., which all seriously affect the performance of current differential protection.
The direction comparison pilot protection mainly uses the phase of the voltage of the same measuring point as reference, obtains the direction information of the fault occurrence point and the measuring point represented by the current relative phase, and sends the direction information to the opposite end of the line, if both sides indicate positive directions, the unit type protection mode can be tripped simultaneously. The protection has the main characteristics that the used communication data volume is small, synchronous sampling at two ends of a line is not needed, and the direction judgment accuracy is influenced when the ratio of voltage to current is too large.
The distance pilot protection mainly uses three-section distance protection as a starting unit and two-section distance protection as a direction criterion, and takes double effects of distance protection and unit protection into consideration, thereby achieving the purpose of simplifying protection configuration. The method does not need synchronous sampling and has small communication data quantity as the direction comparison pilot protection, but has the technical problems of difficult interphase coupling compensation, difficult interference of an opposite terminal system and fault resistance thereof and the like.
The phase differential pilot protection mainly utilizes the phase information of the current phasor differential protection, reduces the requirement of the original protection on communication traffic, and is particularly beneficial to stabilizing the state information of the phase when the phase information of the comprehensive current is adopted. However, since only the phase information of the current phasor is taken, when the interference factors mentioned in the current phasor differential protection are met, the phase deviation is too large, and a protection accident is caused.
Since the conventional relay protection generally adopts electrical parameters which have completely the same properties and can switch roles with each other, the electrical parameters form an action element of related protection and also serve as a limiting threshold of the same protection, the action element and the limiting threshold have a chance of mutual transformation when conditions change from a physical model, the action element and the limiting threshold also have a risk of mutual size reversal from a numerical relationship, and the protection performance is seriously influenced when any one of the action element and the limiting threshold deviates from a normal value from a protection effect. Therefore, to properly configure protection, it is necessary to ensure that the protection performance is definitely reliable and has a complete discrimination margin from the physical model.
In the process of implementing the invention, the inventor finds that the prior art at least has the defects of weak anti-interference capability, low reliability, poor safety and the like.
Disclosure of Invention
The invention aims to provide a comprehensive configuration method for unit protection of an ultrahigh-voltage alternating-current transmission line based on new energy grid connection so as to achieve the advantages of strong anti-interference capability, high reliability and good safety.
In order to achieve the purpose, the invention adopts the technical scheme that: a comprehensive configuration method for unit protection of an extra-high voltage alternating current transmission line based on new energy grid connection mainly comprises the following steps:
a. the method comprises the steps of utilizing current data collected by phases on two sides of a line to conduct qualitative judgment on the running state of the line in real time;
b. b, respectively starting longitudinal impedances of different forms according to the conclusion made by qualitative judgment in the step a; when the transmission line causes the increment of the corresponding current to be effectively measured due to the reason, the corresponding longitudinal impedance algorithm can be started, and whether the internal fault occurs in the line or not can be determined according to the result of the longitudinal impedance.
Further, the step a specifically includes:
using fault component current of sampling value of each phase at two sides of linePower frequency fault component currentAnd full current at power frequencyThe qualitative judgment of the line running state is obtained by calculating the amplitude value according to the actually measured current of each phase in real time;
wherein,and m and n are electrical measuring points at two ends of the line.
Further, the step b specifically includes:
b1, when the current of the sampling value fault component on both sides of the line meets the starting threshold of the emergency state, the sampling value fault component integration/accumulation sum type longitudinal impedance of the timing limit can be started; the integral/cumulative sum type longitudinal impedance of the fault component of the sampling value is mainly used for screening the short-circuit fault of the large current at the protection outlet;
b2, when the current sum of the power frequency fault components on the two sides of the line meets the requirement of stably obtaining a basic measured value, starting the conventional power frequency fault component longitudinal impedance;
b3, when the power frequency fault component current differential integral calculation formula of the timing limit or the inverse time limit on two sides of the line meets the relevant starting threshold, the power frequency fault component integral/accumulation sum type longitudinal impedance of the timing limit or the inverse time limit can be started;
b4, as backup protection, it needs to use a power frequency full current differential integral calculation formula with a timing limit or an inverse time limit, when it reaches the start threshold, it can start the power frequency full integral/accumulation formula longitudinal impedance with timing limit or inverse time limit.
Further, the step b1 specifically includes:
when the current sum of the fault components of the sampling values on two sides of the line meets the following conditions:
wherein, I'setThe value of 0.1A is the current data of the sampling value measured by the secondary side of the line current transformer; t' is 5ms and is the integration time of the current differential of the sampling value; m is the number of sampling data points corresponding to the integration time; k1The number is an integer larger than 1, and the number is a reliable coefficient for screening emergency states; the starting unit can be protected by the formula (1), namely the fault component integration/accumulation and the formula longitudinal impedance of the sampling value capable of starting the timing limit:
in the formula,the voltage difference of the sampling value fault components of two ends of the line which are subjected to zero sequence voltage compensation is obtained;voltage of each sampling value at two sides of the line;the current of each phase of the sampling values at two sides of the line is calculated; u. of0m(t),u0n(t) is the zero sequence voltage of the sampling values at two sides of the line; r ism,r0Mutual resistance and zero sequence resistance of a line with unit length; (rD) is the line series impedance and its associated calculated value; rD is the full-length series resistance of the line.
Further, the step b2 specifically includes:
when the current sum of the power frequency fault components on the two sides of the line meets the following conditions:
wherein, IsetThe line current data obtained by the secondary side of the line current transformer is 0.1A, and the line current data can become a starting unit protected by the formula (2), namely the conventional line frequency fault component longitudinal impedance can be started:
in the formula,the voltage difference of the power frequency fault components of the two ends of the line which are subjected to zero sequence voltage compensation is obtained;the fault components of the power frequency voltage of each phase at two sides of the line are obtained;the fault components of the power frequency current of each phase at two sides of the line are obtained;zero sequence voltage at two sides of the line; z is a radical ofm,z0Is the mutual impedance and zero sequence impedance of the line with unit length; and zD is the full-length series impedance of the line.
Further, the step b4 specifically includes:
as long as the power frequency fault component current differential integral calculation formula of the timing time limit or the inverse time limit at two sides of the line meets the following requirements:
wherein, I'setThe minimum setting value calculated for the power frequency fault component current differential integration, where T ═ 20ms is the power frequency signal period, can also be a starting unit protected by the formula (3), that is, the power frequency fault component integration/accumulation sum formula longitudinal impedance capable of starting a timing period or an inverse timing period:
wherein n is an integer greater than 1; and T is 20ms, which is the power frequency signal period.
Further, step b4 specifically includes:
adding a power frequency full-current differential integral calculation formula with a fixed time limit or an inverse time limit:
wherein, I ″)setThe minimum setting value calculated for the power frequency full-current differential integration can also be used as a starting unit protected by the formula (4), namely, the power frequency full-current integration/accumulation sum type longitudinal impedance of a fixed time limit or an inverse time limit can be started;
the impedance algorithm can be started by a starting unit, can also automatically continuously monitor the running state of the line in real time for a long time without starting:
in the formula,the voltage difference of the power frequency total quantity of the two ends of the line which are subjected to zero sequence voltage compensation;the total power frequency voltage of each phase on both sides of the circuit;the total amount of power frequency current of each phase on both sides of the circuit; kLoadAnd the value of approximately 2-3 is a weighted reliability factor influenced by the load component, and n' is an integer not less than n.
The comprehensive configuration method for the unit protection of the ultrahigh-voltage alternating-current transmission line based on the new energy grid connection of the embodiments of the invention mainly comprises the following steps: the method comprises the steps of utilizing current data collected by phases on two sides of a line to conduct qualitative judgment on the running state of the line in real time; respectively starting longitudinal impedances of different forms according to a conclusion made by qualitative judgment; when the transmission line causes the increment of the corresponding current to be effectively measured due to reasons, the corresponding longitudinal impedance algorithm can be started, and whether the line has an internal fault or not is determined according to the result of the longitudinal impedance; the method can avoid the reduction of the protection performance and even the threat of the protection reliability caused by various interference factors in the existing unit type relay protection of the power transmission line, further improve the adaptation of the power transmission line to different operation modes, and improve the sensitivity and the reliability of fault identification criteria; therefore, the defects of weak interference resistance, low reliability and poor safety in the prior art can be overcome, and the advantages of strong interference resistance, high reliability and good safety are realized.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:
FIG. 1 is a three-phase line model of a fault component of a sampled value according to the present invention;
FIG. 2 is a three-phase line model of a power frequency fault component in the present invention;
FIG. 3 is a three-phase line model of the power frequency total in the present invention;
FIG. 4 is a simplified model of a three-phase line (three phases are balanced) for the power frequency load component of the present invention;
FIG. 5 is a diagram illustrating the relationship between delay time and operation threshold reflected by each vertical impedance algorithm in the present invention.
Detailed Description
The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are described herein for the purpose of illustration and explanation and not limitation.
According to the embodiment of the invention, as shown in fig. 1-5, a comprehensive configuration method for unit protection of an ultrahigh voltage alternating current transmission line based on new energy grid connection is provided, and the specific method relates to a novel combination method for applying longitudinal impedance algorithms in different forms to complex operating environment fault property discrimination, so that the situation that the protection performance is reduced and the protection reliability is threatened due to various interference factors in the unit relay protection of the existing transmission line can be avoided, the transmission line is further improved to adapt to different operating modes, and the sensitivity and the reliability of fault identification criteria are improved.
According to the technical scheme, according to the difference between the operation mode and the state of new energy grid connection and traditional power generation, the initial numerical value of the current at two ends of a line is measured, the initial conclusion of the influence degree of a situation on a system is qualitatively judged, a corresponding longitudinal impedance algorithm is started, and a protection strategy that the real-time operation state of the line is different from a normal state is determined according to the actual calculation results of different longitudinal impedance algorithms. The technical scheme of the invention mainly comprises the following steps: firstly, when the electric state related to the circuit changes due to reasons, sampling value fault component current, power frequency fault component current and power frequency full-scale current of each phase on two sides of the circuit are rapidly collected, and the circuit is qualitatively divided into an emergency state, a general state, a small disturbance state and a slight state according to the calculated amplitude of each phase of measured current; secondly, on the basis of the qualitative analysis conclusion, longitudinal impedance algorithms in different forms are respectively adopted to calculate the results of the longitudinal impedance in a split-phase manner, and the actual property of the state is discriminated according to the obtained results. When the calculated impedance meets the judgment condition, the internal fault is judged sensitively, and a tripping command can be sent out; otherwise, the power transmission line is judged to be a non-internal fault reliably, so that the power transmission line under control can still keep the original stable operation state.
The technical scheme of the invention specifically comprises the following steps:
step 1: and the current data acquired by each phase at two sides of the line is utilized to carry out qualitative judgment on the running state of the line in real time.
For example, using sampled values of the phases on both sides of the line for fault component currentsPower frequency fault component currentAnd full current at power frequency(whereinm and n are electrical measurement points at two ends of the line), and the qualitative judgment of the running state of the line is obtained by calculating the amplitude according to the actually measured current of each phase in real time.
When any state change occurs in the power transmission line, the current of the line changes; that is, when the operating state of the transmission line changes, the change of the line current is reflected. The emergency state, the normal state, the small disturbance state and the slight state of the line can be preliminarily judged according to the magnitude of the current increment, and necessary preparation work is carried out for subsequent processing.
Step 2: based on the conclusions from the above qualitative analysis, different forms of longitudinal impedance are respectively initiated. When the transmission line causes the increment of the corresponding current to be effectively measured due to the reason, the corresponding longitudinal impedance algorithm can be started, and whether the internal fault occurs in the line is determined according to the result of the longitudinal impedance.
The method comprises the steps of when the current of sampling value fault components on two sides of a line and a starting threshold meeting an emergency state are adopted; the fault component integration/accumulation and longitudinal impedance of the sampled values of the timing limit can thus be initiated. The integral/accumulation sum type longitudinal impedance of the fault component of the sampling value is mainly used for screening the short-circuit fault of the large current at the protection outlet, and is one of the important bases of innovation of the invention.
For example, when the sum of currents of fault components of sampling values on both sides of a line satisfies:
wherein, I'setThe value of 0.1A is the current data of the sampling value measured by the secondary side of the line current transformer; t' is 5ms and is the integration time of the current differential of the sampling value; m is the number of sampling data points corresponding to the integration time; k1The number is an integer larger than 1, and the number is a reliable coefficient for screening emergency states; the starting unit can be protected by the formula (1), namely the fault component integration/accumulation and formula longitudinal impedance of the sampling value of the timing limit can be started:
in the formula,the voltage difference of the sampling value fault components of two ends of the line which are subjected to zero sequence voltage compensation is obtained; u. of0m(t),u0n(t) is the zero sequence voltage of the sampling values at two sides of the line; r ism,r0Mutual resistance and zero sequence resistance of a line with unit length; (rD) is the line series impedance and its associated calculated value; the electrical state relationship of the sampled values is shown in figure 1.
The algorithm of the longitudinal impedance in the formula (1) is mainly suitable for the requirement of relay protection discrimination of the power transmission line in an emergency state, and mainly aims at short-circuit faults of large current at a protection outlet. The method of integrating/accumulating and formula is also adopted in the impedance calculation, so that the result of the current differential integration used for starting can be directly quoted to reduce the calculation amount, and meanwhile, the stable effect of the impedance calculation can be enhanced, therefore, the algorithm becomes one of the important bases of the innovative achievement of the invention.
And when the current of the power frequency fault components on two sides of the line meets the requirement of stably obtaining a basic measured value, the conventional power frequency fault component longitudinal impedance can be started. The conventional power frequency fault component longitudinal impedance mainly meets the requirement of relay protection discrimination of a power transmission line under the condition of a common state, and the performance of the conventional power frequency fault component longitudinal impedance is effectively proved and relevant papers are published[1]。
When the current sum of the power frequency fault components on the two sides of the line meets the following conditions:
wherein, IsetThe line current data obtained by the secondary side of the line current transformer is 0.1A, which can be a starting unit protected by the formula (2), namely the conventional line frequency fault component longitudinal impedance can be started:
in the formula,the voltage difference of the power frequency fault components of the two ends of the line which are subjected to zero sequence voltage compensation is obtained;zero sequence voltage at two sides of the line; z is a radical ofm,z0Is the mutual impedance and zero sequence impedance of the line with unit length; the electrical state relationship of the power frequency fault components is shown in figure 2.
The longitudinal impedance algorithm of the formula (1) is obviously superior to the formula (2) and current differential protection in the aspect of state discrimination sensitivity, the action speed is not slower than that of phasor current differential protection, and the method can completely meet the requirement of relay protection discrimination of the power transmission line under the condition of a common state.
And thirdly, when the power frequency fault component current differential integral calculation formula of the timing time limit or the inverse time limit at two sides of the line meets the related starting threshold, the power frequency fault component integral/accumulation sum type longitudinal impedance of the timing time limit or the inverse time limit can be started. The main advantage of the power frequency fault component integration/accumulation and type longitudinal impedance with a fixed time limit or an inverse time limit is that the method can adapt to the requirement of discriminating the relay protection state of the power transmission line in a small disturbance state, is a recent result after strict theoretical analysis and real simulation verification, also becomes an important basis for innovation of the method, and is particularly suitable for the operation condition with small power generation output capacity of new energy.
The method is used as a backup protection, a power frequency full-quantity current differential integral calculation formula with a fixed time limit or an inverse time limit is required to be used, and when the power frequency full-quantity current differential integral calculation formula reaches a starting threshold, the power frequency full-quantity integral/accumulation and longitudinal impedance of the fixed time limit or the inverse time limit can be started, so that the method becomes a main basis for innovation of the method. The device can be used after being started by the starting element, and is more suitable for continuously monitoring the real-time running condition of the line for a long time without starting, so that the device is not limited by any condition and running condition.
The longitudinal impedance is composed of three electrical quantities which are completely different in state, different in calculation form and mutually incapable of being replaced and converted. The effect of triangle-like stability can be obtained from the form of the calculation of the impedance: even if the maximum range of values defined by engineering deviates in any of the three electrical quantities for any reason, without changing their value-to-value relationship with each other for any reason, the reliability and sensitivity of the longitudinal impedance are determined. When two electric quantities have value deviation in a limited range, the discrimination margin of enough value deviation between the two electric quantities can be ensured, and the adaptability and the stability of the longitudinal impedance are established.
Because the longitudinal impedance has unique triangular stability in a calculation structure, the longitudinal impedance can show multiple excellent discrimination characteristics and related performance characteristics in practical application. Among them are:
various adverse effects caused by current transformer transmission errors and electromagnetic saturation can be resisted, so that absolute reliability of purchased unit protection is ensured;
secondly, when the current transformer generates obvious electromagnetic saturation, the longitudinal impedance can also keep a larger discrimination margin, and meanwhile, the influence caused by transmission deviation possibly accompanying the voltage transformer can be resisted;
the voltage difference between two ends of the line forms a certain state complementary correlation characteristic on a physical model and mathematical expression, so that the technical problem of a voltage dead zone encountered by distance protection can be overcome;
the longitudinal impedance has wider adaptability, when the short-circuit capacity of the system is larger than the inherent natural transmission power of the protected power transmission line, the longitudinal impedance can be checked without any parallel capacitance compensation according to the actual operation parameter calculation of the existing AC power transmission line with the highest voltage grade and the longest distance.
Although, the cell protection algorithm proposed by equation (2) and the above performance features have been effectively proven and published in the relevant papers[1](ii) a However, the core of the present invention is to create innovative algorithms for integrating/accumulating and formula longitudinal impedance from the basic protection form of formula (2) longitudinal impedance and its functional features by proposing formula (1), formula (3) and formula (4). The novel algorithm is mainly characterized in that the integral/cumulative sum calculation form is introduced, so that the data such as the voltage term, the current term and the like are ensured to have the amplitude which can be effectively measured in any operation environment, the stability of the calculation result of the longitudinal impedance can be fully guaranteed, and the longitudinal impedance has a key technology for reliably and sensitively screening faults in various complex environments, and also has a key technology for reliably and sensitively screening faults in various complex environmentsThe main technical basis of the invention is provided. The characteristic is particularly suitable for the changeable power transmission operation control mode in a new energy power generation environment and the technical requirement of relay protection in the environment, and meanwhile, the content of the part also becomes an indispensable important component of the comprehensive protection configuration method.
As long as the power frequency fault component current differential integral calculation formula of the timing time limit or the inverse time limit at two sides of the line meets the following requirements:
(wherein l'setThe minimum setting value calculated for the power frequency fault component current differential integration, where T ═ 20ms is the power frequency signal period, may also be a starting unit protected by equation (3), that is, the power frequency fault component integration/accumulation sum equation longitudinal impedance of the timing or inverse time limit may be started:
wherein n is an integer greater than 1; and T is 20ms, which is the power frequency signal period.
The algorithm of the longitudinal impedance of the formula (2) is obviously superior to the formula (2) in the sensitivity of state discrimination. The method has the greatest advantage of being capable of meeting the requirement of discriminating the relay protection state of the power transmission line in a small disturbance state; when the system operation mode is obviously smaller than the conventional minimum operation mode, the short-circuit capacity of the system can be reflected to be obviously smaller than the conventional mode, the fault current can be reduced, and therefore the stable measurement of the power frequency fault current component is influenced. The maximum operation mode mainly depends on the total installed capacity of a wind field, while the minimum operation mode cannot be effectively predicted, and the situation is a technical problem that relay protection of new energy grid connection distribution must face frequently. The algorithm of the formula (2) is an improved algorithm of the formula (1), and is one of the main bases for improving the stability of impedance calculation after rigorous theoretical analysis and real simulation verification and adapting to smaller (new energy power generation) operating environment. The method is mainly characterized in that the stability of impedance calculation is improved due to the fact that the denominator term of the impedance calculation is increased, and the method is particularly suitable for the operation condition that the new energy power generation output capacity is small. In order to form good matching with the conventional power frequency fault component longitudinal impedance on the protection action time limit, the shortest time interval of integration is recommended to be not less than one power frequency period, and a plurality of power frequency periods can be properly prolonged according to the requirement.
In a particular operating mode, for example during reclosing, the fault component cannot be reliably captured,
the invention proposes a power frequency full-current differential integral calculation formula needing to be added with a fixed time limit or an inverse time limit:
wherein, I ″)setThe minimum setting value calculated for the power frequency full-current differential integration can also be used as a starting unit protected by the formula (4), namely, the power frequency full-current integration/accumulation sum type longitudinal impedance of a fixed time limit or an inverse time limit can be started. The impedance algorithm can be started by a starting unit, or can automatically continuously monitor the running state of the line in real time for a long time without starting:
in the formula, KLoadThe value of approximately 2-3 is a weighted reliability factor influenced by the load component, and n' is an integer not less than n; the relation of the electrical state of the power frequency total quantity is shown in figure 3; the electrical state relationship of the load is shown in fig. 4.
The longitudinal impedance algorithm in the formula (4) has the greatest advantage that the impedance calculation formula is accompanied by the influence of a load component, so that the reliability of impedance calculation is improved, and the requirement of stable detection of relay protection of the power transmission line in a slight state can be met. When the longitudinal impedance of the power frequency full quantity is adopted, the action setting impedance value must be correspondingly improved due to the common influence of factors such as load components, fault resistance and the like. The integration algorithm of the formula (4) eliminates various adverse effects brought by new energy power generation in principle, wherein the adverse effects include the effect of unstable load components brought by small wind energy output and the like, and the integration algorithm combines the characteristics and finally becomes one of the innovative main characteristics of the invention. In order to form good matching with the power frequency fault component integration/accumulation sum type longitudinal impedance of a fixed time limit or an inverse time limit on a protection action time limit, the shortest time interval of integration needs to be absolutely more than one power frequency period of the formula (3), and generally, the suitable extension of a plurality of power frequency periods can be considered.
The four algorithms of the longitudinal impedance form a complete unit type relay protection system of the ultrahigh-voltage alternating-current transmission line of the power system based on the new energy grid-connected power generation environment. The protection not only can adapt to all operating environments of new energy grid-connected power generation, form all-weather protection element combination, but also can improve the protection level of the power transmission line in the traditional power generation environment.
That is, the algorithm of the four longitudinal impedances described above: the sampling value fault component integral/accumulation sum type longitudinal impedance can quickly isolate a serious short-circuit fault reflected by an emergency state, the longitudinal impedance of a conventional power frequency fault component can isolate a short-circuit fault corresponding to a general state to play a role of quick main protection, the longitudinal impedance of the power frequency fault component integral type longitudinal impedance can isolate a slight fault applicable to a small disturbance state to form II-stage type unit relay protection with time limit, and the longitudinal impedance of the full power frequency is used as backup protection of the protection, so that a unit type relay protection system of the ultrahigh-voltage alternating-current transmission line of the power system based on a new energy grid-connected power generation environment is formed completely. The protection not only can adapt to all operating environments of new energy grid-connected power generation, forms all-weather protection elements, and can also improve the protection level of the power transmission line in the traditional power generation environment.
In specific implementation, when the state of the actually-operated power transmission line is changed due to a fault, the state characteristics of the line can be qualitatively analyzed according to the degree of the change of the electric quantity of the related line, and the state characteristics can be preliminarily divided into an emergency state, a general state, a small disturbance state and a slight state. According to the fault component network, when a fault occurs, the fault component voltage of a fault point is maximum, and the amplitude of the fault component voltage is gradually reduced along with the fact that an observation point is far away from the fault point until the point position in the system is reduced to zero; the fault component current flows from the fault point to the system midpoint toward the outside. According to the inherent state characteristics formed by the voltage and current signals obtained by the line, the target characteristics and the calculation function for distinguishing the states of the transmission line can be obtained by referring to the electrical distribution parameter characteristics of the transmission line. With the continuous and deep research on the longitudinal impedance, the discrimination characteristics of the impedance can be better exerted, and the application effect and the application range are further expanded. The invention utilizes the discrimination characteristic of longitudinal impedance to construct a new comprehensive configuration scheme of the ultra-high voltage line protection based on new energy power generation. The specific implementation comprises the steps that current and voltage signals of the power transmission line are transmitted to the opposite end of the line through optical fiber communication, the discrimination result of the running state of the line is obtained by utilizing the calculated resistance value obtained by the longitudinal impedance algorithm, and the identification criterion of the protection action is established.
The technical scheme of the invention aims at carrying out the research of the unit type relay protection comprehensive configuration by taking Dunhuang-spring-Jinchang-Yongdeng 750kV ultrahigh voltage power transmission and transformation system which is in charge of wind power delivery in northwest region as a target. Referring to fig. 1, m and n sides of a protection measuring device provided with the distinguishing element of the invention are provided with input quantities of voltage and current fault components of a transmission line, and the voltage and the current are obtained by a voltage transformer and a current transformer on the line side, which are shown in fig. 1 in a simple schematic way. Line voltage and current signals are acquired by a voltage and current transformer, are transmitted to a microcomputer main system after low-pass filtering, sample holding and A/D conversion, and whether the integral longitudinal impedance of the fault component of the sampling value is started or not can be directly determined according to the result of the sum of the current of the fault component of the sampling value; meanwhile, the work frequency component is calculated by a discrete/fast Fourier filtering algorithm, on the basis, whether the longitudinal impedance of the conventional work frequency fault component is started or not is determined according to the result of the sum of the work frequency fault component currents, whether the longitudinal impedance of the power frequency fault component integral type is started or not is determined according to the result of the power frequency fault component current differential integral calculation formula, and whether the longitudinal impedance of the power frequency full-quantity integral type is started or not is determined according to the result of the power frequency full-quantity current differential integral calculation formula. And then judging whether internal faults occur in each phase to which the impedance belongs according to the resistance values of the longitudinal impedances. Similarly, for a line in which (most severe) electromagnetic saturation occurs on the single-ended current transformer, the longitudinal impedance can also accurately judge the actual operating state of the line according to the aforementioned principle. For a line with a voltage transformer transmission error while the current transformer at one end is obviously electromagnetically saturated, the longitudinal impedance still has sufficient discrimination margin, so that the discrimination accuracy is ensured.
For another example, the technical scheme of the invention is a method for relay protection of an extra-high voltage alternating current transmission line of a power system based on a new energy grid-connected power generation operation environment, which is implemented according to the following steps:
step 1: and after wave recording and filtering processing are carried out on the faulted phase voltage and current of the power transmission line, the actual state of the line is analyzed by using different current differential calculation methods. When the current differential result calculated by the line is larger, the state of the corresponding line is more serious, only the delay time of the protection action is shortened, the fault is ensured to be accurately identified, and the damage caused by the fault is reduced.
Step 2: comparing longitudinal impedancesThe impedance in series with the line and the magnitude of its function f (rD) form a reasonable criterion.
When the power grid fails, the values of voltage and current fault components can be measured on the current transformers at the two ends of the protected line, and the starting threshold of related protection can be ensured to be larger than. When the corresponding protection is triggered, the result of the longitudinal impedance corresponding to the out-of-range fault is necessarily greater than the line series impedance and its related function; the results from the in-zone faults are exactly opposite, and the results from the two faults can ensure complete definition. The following criteria can thus be constructed:
when the set protection is started and the criterion meets the action condition, the internal fault can be judged reliably, and when the criterion does not meet the action condition any more, the external fault or the system disturbance is determined, the determination of the system running state can effectively improve the speed of the protection action: an emergency state, a general state, a small disturbance state, and a light state.
Referring to fig. 5, a fault removal timing of a power transmission line, t1At the moment when the transmission line fails, t2The moment is the setting time of the fault component integral/accumulation sum type longitudinal impedance of the sampling value t3The moment is the setting time t of the longitudinal impedance of the fault component of the conventional power frequency4The moment is the setting time of the power frequency fault component integral/accumulation sum type longitudinal impedance, t5The moment is the setting time of the power frequency full integral/accumulation sum type longitudinal impedance. When the transmission line has a fault (the occurrence time is t ═ t)1) After occurrence, i.e. t1＜t＜t2And when the judgment is finished and whether the protection acts is determined, the related calculation is finished. When t is2＜t＜t3When the action threshold is determinedAccording to the method, the requirement of the minimum electrical quantity required by ensuring the stable calculation of the conventional longitudinal impedance is mainly determined, and the method is also a reference target for comparison of other methods, mainly aiming at the discrimination of faults of a power transmission line in a general state, as the conventional power frequency fault component longitudinal impedance, the action delay time can generally reach about 20mS, and when the judgment is finished and whether the protection acts or not is determined, the condition is the same. When t is3＜t＜t4And when the equivalent action threshold value converted at the moment is obviously lower than that of the conventional longitudinal impedance, the equivalent action threshold value is mainly used for discriminating the fault of the power transmission line in a small disturbance state, particularly when the power generation of new energy is in a small-capacity output environment (the operation mode of the equivalent action threshold value is obviously lower than that of a normal minimum operation mode), the equivalent action threshold value is used as the longitudinal impedance of the timing-limited integral/integral sum type power frequency fault component, and the relevant action delay time brought by signal processing is determined to be several times and the power frequency period. When t is4＜t＜t5And the equivalent action threshold value converted at the moment is the lowest, and is mainly used as a timing time limit integral/accumulation sum type power frequency full-quantity longitudinal impedance for discriminating the faults of the power transmission line in a slight state, and the action delay time related to signal processing is the longest. In addition, a curve I is the action characteristic of inverse time limit power frequency fault component integral/accumulation sum type longitudinal impedance; curve ii is the inverse time-limit power frequency fault component integral/accumulation and the action characteristic of longitudinal impedance. According to the qualitative analysis result of the action characteristics, at least more than one specific protection mode can be adapted when the system operates in any mode, the influence of system disturbance can be overcome to the maximum extent in practical application, and the reliability and the sensitivity of protection are ensured, so that a new comprehensive configuration scheme of the unit protection of the ultrahigh-voltage alternating-current transmission line based on new energy grid connection is formed.
According to the technical scheme, in the actual operation of the ultrahigh-voltage power transmission line, the essential numerical value conversion and physical connection characteristics of the model are analyzed according to the inherent electrical characteristics of a fault component network generated by faults, the method for discriminating the fault properties of the power transmission line based on the longitudinal impedance characteristics is provided, the discrimination limit of the longitudinal impedance is only related to the series impedance of the power transmission line, so that the method is not influenced by other factors except the state, and meanwhile, the method is harmoniously and complementarily used with the conventional criterion utilizing the basic electrical characteristics of the power transmission line, and the reliability and the sensitivity of protection can be effectively improved. The method is expected to be an effective means for identifying the novel intelligent unit type fault property of the extra-high voltage long-distance power transmission line based on new energy grid-connected power generation. The technical scheme of the invention can also be used as effective supplement of the fault split-phase electrical quantity characteristic criterion for the relay protection of the transmission line of the traditional power generation. On the basis of the increasingly mature technologies of high-performance microcomputer protection, wide-frequency-domain digital communication and intelligent electronic mutual inductance processing, the technical scheme of the invention has good application prospect.
To further illustrate the main performance features of the present invention, a three-phase line model of the power frequency fault component is presented in fig. 1. In fig. 1, m and n are electrical measurement points at two ends of a line; and obtaining power frequency fault components of voltages and currents of each phase of the line in real time from measuring points at two ends;respectively, a fault point equivalent voltage and a fault current; rFIs a fault point fault resistance; d and D are the total length of the protected line and the line length from the measuring point m to the fault point respectively; z is a radical ofs,z1,zmRespectively the self impedance, the positive sequence impedance and the mutual impedance of the single-bit length line; zsm(Lsm),Zmm(Lmm),Z1m(L1m)，Zsn(Lsn),Zmn(Lmn) And Z1n(L1n) Respectively, the self-impedance (inductance), the positive sequence impedance (inductance) and the mutual impedance (inductance) of the system on both sides of the line.
Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (7)
1. A new energy-based integrated configuration method for unit protection of an alternating current transmission line is characterized by mainly comprising the following steps:
a. the method comprises the steps of utilizing current data collected by phases on two sides of a line to conduct qualitative judgment on the running state of the line in real time;
b. b, respectively starting longitudinal impedances of different forms according to the conclusion made by qualitative judgment in the step a; when the transmission line causes the increment of the corresponding current to be effectively measured due to the reason, the corresponding longitudinal impedance algorithm can be started, and whether the internal fault occurs in the line or not can be determined according to the result of the longitudinal impedance.
2. The integrated configuration method for the unit type protection of the extra-high voltage alternating current transmission line according to claim 1, wherein the step a specifically comprises:
using fault component current of sampling value of each phase at two sides of linePower frequency fault component currentAnd full current at power frequencyThe qualitative judgment of the line running state is obtained by calculating the amplitude value according to the actually measured current of each phase in real time;
wherein,and m and n are electrical measuring points at two ends of the line.
3. The comprehensive configuration method for the unit type protection of the extra-high voltage alternating current transmission line based on the new energy grid connection according to claim 1 or 2, wherein the step b specifically comprises the following steps:
b1, when the current of the sampling value fault component on both sides of the line meets the starting threshold of the emergency state, the sampling value fault component integration/accumulation sum type longitudinal impedance of the timing limit can be started; the integral/cumulative sum type longitudinal impedance of the fault component of the sampling value is mainly used for screening the short-circuit fault of the large current at the protection outlet;
b2, when the current sum of the power frequency fault components on the two sides of the line meets the requirement of stably obtaining a basic measured value, starting the conventional power frequency fault component longitudinal impedance;
b3, when the power frequency fault component current differential integral calculation formula of the timing limit or the inverse time limit on two sides of the line meets the relevant starting threshold, the power frequency fault component integral/accumulation sum type longitudinal impedance of the timing limit or the inverse time limit can be started;
b4, as backup protection, it needs to use a power frequency full current differential integral calculation formula with a timing limit or an inverse time limit, when it reaches the start threshold, it can start the power frequency full integral/accumulation formula longitudinal impedance with timing limit or inverse time limit.
4. The comprehensive configuration method for the unit type protection of the extra-high voltage alternating current transmission line based on the new energy grid connection according to claim 3, wherein the step b1 specifically comprises the following steps:
when the current sum of the fault components of the sampling values on two sides of the line meets the following conditions:
wherein, I'setThe value of 0.1A is the current data of the sampling value measured by the secondary side of the line current transformer; t' is 5ms and is the integration time of the current differential of the sampling value; m is the number of sampling data points corresponding to the integration time; k1The number is an integer larger than 1, and the number is a reliable coefficient for screening emergency states; can become a starting unit for the protection of the formula (1), namely, the integration/accumulation of fault components of sampling values and the longitudinal impedance of the formula capable of starting the timing limit
In the formula,the voltage difference of the sampling value fault components of two ends of the line which are subjected to zero sequence voltage compensation is obtained;voltage of each sampling value at two sides of the line;the current of each phase of the sampling values at two sides of the line is calculated; u. of0m(t),u0n(t) is the zero sequence voltage of the sampling values at two sides of the line; r ism,r0Mutual resistance and zero sequence resistance of a line with unit length; (rD) is the line series impedance and its associated calculated value; rD is the full-length series resistance of the line.
5. The comprehensive configuration method for the unit type protection of the extra-high voltage alternating current transmission line based on the new energy grid connection according to claim 4, wherein the step b2 specifically comprises the following steps:
when the current sum of the power frequency fault components on the two sides of the line meets the following conditions:
wherein, IsetThe line current data obtained by the secondary side of the line current transformer is 0.1A, and the line current data can become a starting unit protected by the formula (2), namely the conventional line frequency fault component longitudinal impedance can be started:
in the formula,the voltage difference of the power frequency fault components of the two ends of the line which are subjected to zero sequence voltage compensation is obtained;the fault components of the power frequency voltage of each phase at two sides of the line are obtained;the fault components of the power frequency current of each phase at two sides of the line are obtained;zero sequence voltage at two sides of the line; z is a radical ofm,z0Is the mutual impedance and zero sequence impedance of the line with unit length; and zD is the full-length series impedance of the line.
6. The comprehensive configuration method for the unit type protection of the extra-high voltage alternating current transmission line based on the new energy grid connection according to claim 5, wherein the step b4 specifically comprises the following steps:
as long as the power frequency fault component current differential integral calculation formula of the timing time limit or the inverse time limit at two sides of the line meets the following requirements:
wherein, I'setThe minimum setting value calculated for the power frequency fault component current differential integration, where T ═ 20ms is the power frequency signal period, can also be a starting unit protected by the formula (3), that is, the power frequency fault component integration/accumulation sum formula longitudinal impedance capable of starting a timing period or an inverse timing period:
wherein n is an integer greater than 1; and T is 20ms, which is the power frequency signal period.
7. The comprehensive configuration method for the unit type protection of the extra-high voltage alternating current transmission line based on the new energy grid connection according to claim 6, wherein the step b4 specifically comprises the following steps:
adding a power frequency full-current differential integral calculation formula with a fixed time limit or an inverse time limit:
wherein, I ″)setThe minimum setting value calculated for the power frequency full-current differential integration can also be used as a starting unit protected by the formula (4), namely, the power frequency full-current integration/accumulation sum type longitudinal impedance of a fixed time limit or an inverse time limit can be started;
the impedance algorithm can be started by a starting unit, can also automatically continuously monitor the running state of the line in real time for a long time without starting:
in the formula,the voltage difference of the power frequency total quantity of the two ends of the line which are subjected to zero sequence voltage compensation;the total power frequency voltage of each phase on both sides of the circuit;the total amount of power frequency current of each phase on both sides of the circuit; kLoadAnd the value of approximately 2-3 is a weighted reliability factor influenced by the load component, and n' is an integer not less than n.
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105896485A (en) * | 2016-02-05 | 2016-08-24 | 国网甘肃省电力公司 | Extra-high voltage long-distance DC line protection algorithm based on new energy grid connection |
| CN106066451A (en) * | 2016-08-01 | 2016-11-02 | 西安工程大学 | A kind of T-type line based on longitudinal impedance protection computational methods |
| CN107516880A (en) * | 2017-09-06 | 2017-12-26 | 中国电力科学研究院 | A kind of false synchronous differential impedance protection phase-selecting method of half-wave power transmission circuit and device |
| CN109799424A (en) * | 2019-01-18 | 2019-05-24 | 西安工程大学 | T-type line fault distance-finding method based on longitudinal impedance |
| CN110907746A (en) * | 2018-09-18 | 2020-03-24 | 深圳供电局有限公司 | High-voltage alternating-current line open-circuit fault identification method, device, equipment and storage medium |
| CN110932248A (en) * | 2019-12-31 | 2020-03-27 | 济南大学 | Micro-grid protection method based on impedance characteristics |
| CN118137436A (en) * | 2024-05-08 | 2024-06-04 | 昆明理工大学 | Inverse time-limited backup protection method for long-distance alternating-current transmission line |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109193586A (en) * | 2018-09-30 | 2019-01-11 | 西安工程大学 | A kind of both-end HVDC transmission line differential relaying algorithm |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1599181A (en) * | 2004-07-21 | 2005-03-23 | 烟台东方电子信息产业股份有限公司 | Negative-sequence longitudinal differential element for electric system |
| CN101707361A (en) * | 2009-11-19 | 2010-05-12 | 四川省电力公司 | Circuit weak feedback side protection self-adapting start distinguishing method |
| CN103683233A (en) * | 2013-12-24 | 2014-03-26 | 南京南瑞继保电气有限公司 | Pilot protection method for automatically adapting power converse of power transmission line |
-
2014
- 2014-10-31 CN CN201410602713.5A patent/CN104362600B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1599181A (en) * | 2004-07-21 | 2005-03-23 | 烟台东方电子信息产业股份有限公司 | Negative-sequence longitudinal differential element for electric system |
| CN101707361A (en) * | 2009-11-19 | 2010-05-12 | 四川省电力公司 | Circuit weak feedback side protection self-adapting start distinguishing method |
| CN103683233A (en) * | 2013-12-24 | 2014-03-26 | 南京南瑞继保电气有限公司 | Pilot protection method for automatically adapting power converse of power transmission line |
Non-Patent Citations (1)
| Title |
|---|
| 刘凯 等: "基于故障分量正序、负序和零序综合阻抗的线路纵联保护新原理", 《电力自动化设备》 * |
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| CN106066451A (en) * | 2016-08-01 | 2016-11-02 | 西安工程大学 | A kind of T-type line based on longitudinal impedance protection computational methods |
| CN106066451B (en) * | 2016-08-01 | 2019-01-18 | 西安工程大学 | A kind of T-type line protection calculation method based on longitudinal impedance |
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| CN110907746A (en) * | 2018-09-18 | 2020-03-24 | 深圳供电局有限公司 | High-voltage alternating-current line open-circuit fault identification method, device, equipment and storage medium |
| CN109799424A (en) * | 2019-01-18 | 2019-05-24 | 西安工程大学 | T-type line fault distance-finding method based on longitudinal impedance |
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