WO2019047610A1 - Small-current grounding fault line selection system and method having backup function - Google Patents

Small-current grounding fault line selection system and method having backup function Download PDF

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WO2019047610A1
WO2019047610A1 PCT/CN2018/094603 CN2018094603W WO2019047610A1 WO 2019047610 A1 WO2019047610 A1 WO 2019047610A1 CN 2018094603 W CN2018094603 W CN 2018094603W WO 2019047610 A1 WO2019047610 A1 WO 2019047610A1
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line
fault
trip
amount
circuit breaker
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PCT/CN2018/094603
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French (fr)
Chinese (zh)
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李晓明
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李晓明
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
    • G01R31/52—Testing for short-circuits, leakage current or ground faults
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/08—Locating faults in cables, transmission lines, or networks
    • G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
    • G01R31/086—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution networks, i.e. with interconnected conductors
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
    • H02H3/16—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to fault current to earth, frame or mass

Definitions

  • the invention relates to a small current ground fault line selection system and method with backup function.
  • a single-phase ground fault occurs in a small-current grounded power system, the ground current is relatively small, and the small-current ground fault line selection device may malfunction.
  • the existing small current ground fault line selection device has a maximum correct action rate of only 99%.
  • a common disadvantage of existing small current ground fault line selection devices is that there is no backup function. In the case of a faulty line selection device for a small current ground fault, the fault line can only be found by manually pulling the power outage. Due to the existing small current ground fault line selection method and the correct operation rate of the device, the non-fault line is often manually pulled and power-off, which reduces the reliability of the power supply system.
  • the present invention proposes a small current ground fault line selection system and method with backup function. After the main protection malfunction, the backup protection can quickly jump off the fault line, and the original small current is grounded. Based on the correct action rate of the fault line selection method, the accuracy of the motion is further improved, and the sensitivity and reliability of the protection are improved.
  • a small current ground fault line selection system with backup function includes a primary protection system and at least one backup protection system.
  • the backup protection system calculates the fault quantity change before and after the circuit breaker trips of each line.
  • the integral of the absolute value, and the failure amount change is used as the action criterion to judge the trip line and realize the sensitive action.
  • the amount of fault change before and after tripping of the circuit breaker using the real fault line is greater than the amount of fault change before and after tripping of the circuit breaker of other non-faulty lines or / and the reverse direction of the fault amount change before and after tripping of the circuit breaker of the real fault line is equal to the trip line
  • the fault quantity change before and after the circuit breaker trips is the action criterion, and the backup protection trip line is judged.
  • a small current ground fault line selection method with backup function the main protection system performs a fault line selection task, if the main protection system correctly selects the fault line, jumps off the selected fault line, and the task is completed;
  • the backup protection system calculates the integral of the absolute value of the fault change before and after the circuit breaker trips of each line, and uses the fault quantity change as an action criterion to determine the trip line and achieve a sensitive action.
  • the adjustment is the integral of the bus zero-sequence voltage amplitude, or the zero-sequence current amplitude of the protected line, or the absolute value of the protected line fault.
  • the value of the adjustment term is an absolute value of the integral value of the integral value of the change in the absolute value of the fault amount before and after the trip of the circuit breaker of the protected line and the absolute value of the change in the fault amount before and after the circuit breaker trip of the trip line.
  • the value of the adjustment term is the integral of the absolute value of the sum of the fault amount change before and after the trip of the circuit breaker of the protected line and the fault amount change before and after the circuit breaker trip of the trip line.
  • the centralized fault line selection system collects all the information into one device and establishes the communication of all line fault information. Therefore, the centralized fault line selection system has more line selection methods, including the following methods. Better improve the sensitivity and reliability of line protection actions.
  • the fault amount is a zero sequence component of the power frequency, or a higher harmonic component, or a zero mode component containing a high frequency, or a zero modulus component of a certain spectrum segment.
  • the small current ground fault line selection method with backup function proposed by the present invention further improves the correct action rate
  • the backup protection action criterion proposed by the present invention applies the feature that “the fault amount of the faulty circuit before and after the circuit breaker trips is relatively large, and the fault amount is changed before and after the circuit breaker trips of other non-faulty lines”, and the “reality” is also applied.
  • the reverse direction of the change in the amount of failure before and after the trip of the circuit breaker of the fault line is equal to the change of the fault amount before and after the circuit breaker trip of the trip line.
  • the backup protection action criterion proposed by the invention can automatically change the unbalanced current and the interference signal of the non-faulty line into the braking amount, thereby improving the reliability of the judgment result.
  • the backup protection can quickly jump off the faulty line.
  • the sum of the action time of the primary protection and the backup protection, plus the sum of the trip times of the two line breakers, does not exceed 100 milliseconds.
  • the invention can be designed and manufactured by using the prior art, can be completely realized, and has broad application prospects.
  • Figure 1 is a schematic diagram of a distributed fault line selection system for a small current grounded power system.
  • Figure 2 is a schematic diagram of a centralized fault line selection system for a small current grounded power system.
  • the present invention proposes a The small current grounding fault line selection method of the backup function improves the correct operation rate of the small current ground fault line selection device.
  • An exemplary embodiment of the present invention is a distributed fault line selection system for a small current grounding system having a backup function, and the power source E supplies power to the bus M.
  • the six lines are L1, L2, L3, L4, L5, and L6.
  • Each line is provided with a set of small current ground fault line selection devices, namely BH1, BH2, BH3, BH4, BH5, BH6.
  • the devices to which each line belongs do not receive the zero sequence current of other lines.
  • the small current ground fault line selection device determines that the power system has a ground fault from the input information of the voltage transformer, the line selection process begins. It is customary to refer to a distributed small current ground fault line selection device as a protection device.
  • the method for selecting a small current ground fault with the backup function proposed by the invention needs to borrow the original small current ground fault line selection method, and the original small current ground fault line selection method and device are called main protection.
  • the primary protection performs the first fault line selection task. If the primary protection has correctly selected the faulty line. After the faulty line trips, the fault quantity disappears, and the small current ground fault line selection device is reset and the task is completed. If the main protection line selection is incorrect and the non-fault line breaker is accidentally tripped, the amount of fault in the power system still exists.
  • the small current ground fault line selection device automatically inputs the backup function, performs the second line selection, and trips the fault line.
  • the fallback feature can also be called backup protection.
  • the main protection method for small current ground faults can be used by existing methods. No longer tired.
  • the backup protection application of the invention applies the feature that the failure amount of the circuit breaker before and after the trip of the real fault line is relatively large, which is larger than the fault amount before and after the trip of the circuit breaker of the other non-fault line, and the circuit breaker of the real fault line is also applied.
  • the reverse direction of the change in the amount of failure before and after the trip is equal to the change in the amount of failure before and after the trip of the trip circuit of the trip line.
  • the fault quantity may be a zero sequence component of the power frequency, may be a high order harmonic component, may be a zero mode component containing a high frequency, may be a zero mode component of a certain spectrum section, or other fault feature quantity.
  • the fault amount i CH (t) takes the periodic function signal i CH (t)
  • i CH (t-MT) represents the periodic function signal of the line before the circuit breaker trips
  • i CH (t) indicates that the line trips at the circuit breaker
  • the reverse direction of the difference between the fault amount before the circuit breaker trip of the real fault line and the fault amount after the trip of the circuit breaker is equal to the fault amount before the circuit breaker trip of the trip line and after the trip of the circuit breaker
  • the integral of the absolute value of the fault quantity described in this paper is the integral of the absolute value of the phasor.
  • the integral of the absolute value of the phasor is the amplitude of the power frequency phasor;
  • the integral of the absolute value of the function signal is the integral of the time period from 0 to MT seconds divided by 2M ⁇ after taking the absolute value.
  • the fault amount is expressed as i CH (t) whether it is a power frequency zero sequence current or a periodic function signal.
  • the difference between the amount of fault before the breaker trips and the fault after the breaker trips is expressed as ⁇ i CH (t).
  • the integral of the absolute value of the difference between the fault amount before the circuit breaker trips and the fault amount after the circuit breaker trips is briefly expressed as the integral of the absolute value of the fault amount change before and after the circuit breaker trips, and is expressed as ⁇ I CH .
  • Backup protection method 1 When ⁇ I CH ⁇ (I set, 1 + k 1 A), the protected line is the faulty line.
  • I set, 1 is the first preset threshold of the protected line
  • k 1 is the first proportional coefficient of the protected line, set according to experience
  • A is the amount of the protected line proportional to the unbalanced ⁇ I CH
  • ⁇ I CH is The integral of the absolute value of the change in the amount of failure before and after the trip of the circuit breaker of the protection line.
  • a single-phase ground fault occurs in one line of a small current grounding system.
  • the fault quantity of a non-fault line (for example, capacitive zero-sequence current) flows from the bus line to the line and then flows into the earth.
  • the earth cannot store current, and the fault amount of all non-faulty lines flowing into the earth flows into the fault line from the fault point of the fault line and flows back to the bus line from the fault line. If the main protection trips by mistake, the amount of fault that the trip line flows into the earth is cut off. The disconnection of the trip line fault amount does not affect the fault amount of the non-fault line outside the trip line. The fault amount of these non-fault lines flowing into the earth remains unchanged before the trip of the circuit breaker and after the trip.
  • the disconnection of the fault line of the trip line will affect the fault quantity of the real fault line.
  • the fault quantity of the real fault line will change before and after the circuit breaker trips.
  • the change of the fault quantity of the real fault line is equal to the change of the fault quantity of the trip line, but the change The direction is just the opposite.
  • the greater the amount of faults in the trip line disconnection the greater the change in the true fault line fault amount.
  • the fault line selection method of the main protection is generally to select the line with a large fault to trip. Therefore, if the main protection fails, the fault of the real fault line is relatively large after the line breaker trips.
  • the first preset threshold I set,1 and the first proportional coefficient k 1 are set reasonably; ⁇ I CH ⁇ (I set,1 +k 1 A) can be guaranteed.
  • the integral of the absolute value of the change in the amount of failure of the non-faulty line outside the trip line is equal to zero before and after the circuit breaker trips, and is not equal to zero in practice.
  • the integral of the absolute value of the change in the amount of failure not equal to zero is called the imbalance ⁇ I CH .
  • the braking amount in the action criterion is automatically adjusted, the imbalance ⁇ I CH is large, the braking effect is large; the unbalance ⁇ I CH is small, and the braking effect is small.
  • the fault line selection action criterion is not only highly sensitive, but also has high reliability.
  • the backup protection method 1 does not Will malfunction.
  • FIG. 2 Another exemplary embodiment of the present invention, as shown in FIG. 2, has a backup function of a small current grounding system centralized fault line selection system, and a power source E supplies power to the bus line M.
  • the six lines are L1, L2, L3, L4, L5, and L6.
  • the centralized fault line selection system Since the information obtained by the centralized fault line selection system contains all the information of the distributed fault line selection system, all methods of the distributed fault line selection system can be transplanted into the centralized fault line selection system. Since the centralized fault line selection system concentrates all information into one device and establishes mutual communication of all line fault information, the centralized fault line selection system method can be more diverse than the distributed fault line selection system.
  • the integral of the absolute value of the failure amount change before and after the circuit breaker trip of the non-faulty line approaches zero, so the operation amount ⁇ I CH,i of the operation criterion of the backup protection method 2 of the non-fault line approaches zero.
  • the integral of the absolute value of the failure amount change before and after the circuit breaker trip of the trip line is ⁇ I CH,g , so the braking amount of the operation criterion of the backup protection method 2 of the non-fault line is (I set, 2, i + k 2,i
  • the backup protection method 2 of the non-faulty line does not work reliably.
  • the integral of the absolute value of the fault quantity change before and after the circuit breaker trip of the real fault line is equal to the integral ⁇ I CH,g of the absolute value of the fault quantity change before and after the circuit breaker trip of the trip line, so the true fault line
  • the braking amount of the action criterion of the backup protection method 2 of the real fault line is I set, 2, i .
  • Reasonably set I set, 2, i the backup protection method of the real fault line 2 sensitive action.
  • the backup protection method 2 applies the feature that the absolute value integral of the fault quantity change before and after the circuit breaker trip of the real fault line is equal to the absolute value integral of the fault quantity change before and after the circuit breaker trip of the trip line, taking two The difference between the integral subtraction and the absolute value is taken as the braking amount, and the characteristics after the integration of the two functions are applied.
  • the backup protection method 3 applies the feature that the reverse direction of the fault quantity change before and after the circuit breaker trips of the real fault line is equal to the fault quantity change before and after the circuit breaker trip of the trip line. Before the two functions are integrated, the two functions are in the opposite direction, so that the two functions are added together and are actually subtracted.
  • the backup protection method 3 is particularly suitable for applications where the fault quantity change before and after the circuit breaker trip of the non-faulty line is not close to zero, the unbalanced current is relatively large, and the interference signal is relatively strong.
  • the backup protection method 3 can automatically change the unbalanced current and the interference signal of the non-faulty line into the braking amount, thereby improving the reliability of the judgment result.
  • the integral of the absolute value of the fault change before and after the circuit breaker trips of all the lines has the characteristics of the non-fault line, so the ground fault occurred by the bus, the backup protection method 2, or the method 3 will not malfunction.
  • Backup protection method 4 In addition to the trip line, the integral of the absolute value of the fault quantity change before and after the circuit breaker trips ⁇ I CH, i the maximum line is the pending fault line.
  • Backup protection method 5 In addition to the trip line, the integral value of the absolute value of the fault amount change before and after the trip of the circuit breaker is subtracted from the absolute value of the integral value of the absolute value of the fault amount change before and after the circuit breaker trip of the trip line
  • the smallest line is the pending fault line.
  • the result of the backup protection method 4 and method 5 is the fault line. If the ground fault occurs on the bus, the result of the backup protection method 4 and method 5 is wrong. Since it is not known whether the ground fault occurs on the line, the results of the backup protection method 4 and method 5 cannot be finalized and can only be determined.
  • the backup protection method 4 and the method 5 cannot be applied separately, and must be applied together with the backup protection method 1, or the method 2, or the method 3 to further improve the reliability of the backup protection method 1, or the method 2, or the method 3.
  • the backup protection can be quickly put into operation without having to wait for the reclosing of the false trip line to complete the backup protection. After the backup protection selects the faulty line, it can quickly trip. In this way, even if the main protection malfunctions, the backup protection can quickly trip the faulty line.
  • the sum of the action time of the primary protection and the backup protection, plus the sum of the trip times of the two line breakers, does not exceed 100 milliseconds.
  • the method for selecting a small current ground fault with a backup function of the invention can be completely realized, and has broad application prospects.

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Abstract

Disclosed in the present invention are a small-current grounding fault line selection system and method having a backup function; when a main protection malfunctions and circuit breakers of non-fault lines trip, a backup protection system calculates the integrals of absolute values of changes in failure quantity before and after the tripping of the circuit breakers of lines; and a backup protection tripping line is determined in accordance with the characteristics of the integrals, achieving rapid response of backup protection. In the present invention, the backup protection can trip a fault line quickly, improving the reliability of protection.

Description

一种具有后备功能的小电流接地故障选线***及方法Small current ground fault line selection system and method with backup function 技术领域Technical field
本发明涉及一种具有后备功能的小电流接地故障选线***及方法。The invention relates to a small current ground fault line selection system and method with backup function.
背景技术Background technique
小电流接地电力***发生单相接地故障，接地电流比较小，小电流接地故障选线装置可能误动作。现有的小电流接地故障选线装置，最高正确动作率只有99％。现有的小电流接地故障选线装置的共同缺点是，没有后备功能。小电流接地故障选线装置一旦发生错误选线，只能采用依次手动拉闸停电的方法找出故障线路。由于现有的小电流接地故障选线方法及其装置正确动作率不高，经常造成非故障线路手动拉闸、停电，降低了电力***供电可靠性。A single-phase ground fault occurs in a small-current grounded power system, the ground current is relatively small, and the small-current ground fault line selection device may malfunction. The existing small current ground fault line selection device has a maximum correct action rate of only 99%. A common disadvantage of existing small current ground fault line selection devices is that there is no backup function. In the case of a faulty line selection device for a small current ground fault, the fault line can only be found by manually pulling the power outage. Due to the existing small current ground fault line selection method and the correct operation rate of the device, the non-fault line is often manually pulled and power-off, which reduces the reliability of the power supply system.
发明内容Summary of the invention
本发明为了解决上述问题，提出了一种具有后备功能的小电流接地故障选线***及方法，本发明在主保护误动作后，后备保护能很快地跳开故障线路，在原有小电流接地故障选线方法正确动作率的基础上，进一步提高动作的准确性，提高保护的灵敏度和可靠性。In order to solve the above problems, the present invention proposes a small current ground fault line selection system and method with backup function. After the main protection malfunction, the backup protection can quickly jump off the fault line, and the original small current is grounded. Based on the correct action rate of the fault line selection method, the accuracy of the motion is further improved, and the sensitivity and reliability of the protection are improved.
为了实现上述目的，本发明采用如下技术方案：In order to achieve the above object, the present invention adopts the following technical solutions:
一种具有后备功能的小电流接地故障选线***，包括主保护***和至少一套后备保护***，当主保护***故障时，由后备保护***计算各条线路的断路器跳闸前后的故障量变化的绝对值的积分，并将该故障量变化作为动作判据，判断跳闸线路，实现灵敏动作。A small current ground fault line selection system with backup function includes a primary protection system and at least one backup protection system. When the primary protection system fails, the backup protection system calculates the fault quantity change before and after the circuit breaker trips of each line. The integral of the absolute value, and the failure amount change is used as the action criterion to judge the trip line and realize the sensitive action.
利用真实故障线路的断路器跳闸前后的故障量变化量大于其他非故障线路的断路器跳闸前后的故障量变化量或/和真实故障线路的断路器跳闸前后的故障量变化的反方向等于跳闸线路的断路器跳闸前后的故障量变化为动作判据，判断后备保护跳闸线路。The amount of fault change before and after tripping of the circuit breaker using the real fault line is greater than the amount of fault change before and after tripping of the circuit breaker of other non-faulty lines or / and the reverse direction of the fault amount change before and after tripping of the circuit breaker of the real fault line is equal to the trip line The fault quantity change before and after the circuit breaker trips is the action criterion, and the backup protection trip line is judged.
一种具有后备功能的小电流接地故障选线方法，主保护***执行故障选线任务，如果主保护***正确选择出故障线路，跳开选择的故障线路，任务完成；A small current ground fault line selection method with backup function, the main protection system performs a fault line selection task, if the main protection system correctly selects the fault line, jumps off the selected fault line, and the task is completed;
如果主保护***故障，由后备保护***计算各条线路的断路器跳闸前后的故障量变化的绝对值的积分，并将该故障量变化作为动作判据，判断跳闸线路，实现灵敏动作。If the primary protection system fails, the backup protection system calculates the integral of the absolute value of the fault change before and after the circuit breaker trips of each line, and uses the fault quantity change as an action criterion to determine the trip line and achieve a sensitive action.
计算每条被保护线路的断路器跳闸前后的故障量变化的绝对值的积分值，积分值大于制动量的对应的线路是故障线路，所述制动量为对应线路的预设整定值和一个与故障特征不平衡量成比例的调整项之和。Calculating the integral value of the absolute value of the fault amount change before and after the circuit breaker tripping of each protected line, and the corresponding line whose integral value is greater than the braking amount is the fault line, and the braking amount is the preset setting value of the corresponding line and A sum of adjustments proportional to the amount of fault characteristic imbalance.
调整项是母线零序电压幅值，或被保护线路零序电流幅值，或被保护线路故障量的绝对值的积分。The adjustment is the integral of the bus zero-sequence voltage amplitude, or the zero-sequence current amplitude of the protected line, or the absolute value of the protected line fault.
调整项的值为对应被保护线路的断路器跳闸前后的故障量变化的绝对值的积分与跳闸线路的断路器跳闸前后的故障量变化的绝对值的积分差值的绝对值。The value of the adjustment term is an absolute value of the integral value of the integral value of the change in the absolute value of the fault amount before and after the trip of the circuit breaker of the protected line and the absolute value of the change in the fault amount before and after the circuit breaker trip of the trip line.
调整项的值为对应被保护线路的断路器跳闸前后的故障量变化与跳闸线路的断路器跳闸前后的故障量变化之和的绝对值的积分。The value of the adjustment term is the integral of the absolute value of the sum of the fault amount change before and after the trip of the circuit breaker of the protected line and the fault amount change before and after the circuit breaker trip of the trip line.
集中式故障选线***把所有信息都集中到一个装置里，建立了所有线路故障信息的相互沟通，因此，集中式故障选线***的选线方法更多样，还包括以下几种方式，能够更好的提高线路保护动作的灵敏度和可靠性。The centralized fault line selection system collects all the information into one device and establishes the communication of all line fault information. Therefore, the centralized fault line selection system has more line selection methods, including the following methods. Better improve the sensitivity and reliability of line protection actions.
方式一：当有被保护线路同时满足以下两条判据时，确定该被保护线路为故障线路：Manner 1: When the protected line meets the following two criteria, it is determined that the protected line is a faulty line:
(1)计算被保护线路的断路器跳闸前后的故障量变化的绝对值的积分值大于制动量，制动量为对应线路的预设整定值和一个与故障特征不平衡量成比例的调整项之和；(1) Calculate the integral value of the absolute value of the fault quantity change before and after the trip of the circuit breaker of the protected line is greater than the braking quantity, the braking quantity is the preset setting value of the corresponding line and an adjustment item proportional to the unbalanced quantity of the fault characteristic Sum;
(2)除去跳闸线路，被保护线路断路器跳闸前后的故障量变化的绝对值的积分最大。(2) Except for the trip line, the integral of the absolute value of the change in the amount of failure before and after the trip of the protected circuit breaker is maximized.
方式二：当有被保护线路同时满足以下两条判据时，确定该被保护线路为故障线路：Manner 2: When the protected line meets the following two criteria, it is determined that the protected line is a faulty line:
(1)除去跳闸线路，线路的断路器跳闸前后的故障量变化的绝对值的积分减去跳闸线路的断路器跳闸前后的故障量变化的绝对值的积分之差的绝对值最小；(1) In addition to the trip line, the integral value of the absolute value of the change in the amount of failure before and after the trip of the circuit breaker of the line is subtracted from the absolute value of the integral of the absolute value of the change in the amount of the fault before and after the circuit breaker trip of the trip line is minimum;
(2)被保护线路的断路器跳闸前后的故障量变化的绝对值的积分值大于制动量，制动量为对应线路的预设整定值和一个与故障特征不平衡量成比例的调整项之和。(2) The integral value of the absolute value of the fault amount change before and after the trip of the circuit breaker of the protected line is greater than the braking amount, and the braking amount is the preset setting value of the corresponding line and an adjustment item proportional to the unbalance amount of the fault characteristic. with.
进一步的，所述故障量是工频的零序分量，或高次的谐波分量，或含有高频的零模分量，或某一频谱区段的零模分量。Further, the fault amount is a zero sequence component of the power frequency, or a higher harmonic component, or a zero mode component containing a high frequency, or a zero modulus component of a certain spectrum segment.
当主保护***内跳闸后，如果电压故障量没有消失，则说明故障选线错误，后备保护***即可投入，不必等待误跳闸线路的重合闸完成。When the main protection system trips, if the voltage fault does not disappear, it indicates that the fault line selection is wrong, and the backup protection system can be put in, without waiting for the reclosing of the false trip line to be completed.
与现有技术相比，本发明的有益效果为：Compared with the prior art, the beneficial effects of the present invention are:
在原有小电流接地故障选线方法正确动作率的基础上，本发明提出的具有后备功能的小电流接地故障选线方法进一步提高了正确动作率；Based on the correct action rate of the original small current ground fault line selection method, the small current ground fault line selection method with backup function proposed by the present invention further improves the correct action rate;
本发明提出的后备保护动作判据应用了“真实故障线路的断路器跳闸前后的故障量变化比较大，大于其他非故障线路的断路器跳闸前后的故障量变化”的特征，还应用了“真实故障线路的断路器跳闸前后的故障量变化的反方向等于跳闸线路的断路器跳闸前后的故障量变化”的特征。两项特征的应用，使后备保护方法有很高的灵敏度，且有很高的可靠性。The backup protection action criterion proposed by the present invention applies the feature that “the fault amount of the faulty circuit before and after the circuit breaker trips is relatively large, and the fault amount is changed before and after the circuit breaker trips of other non-faulty lines”, and the “reality” is also applied. The reverse direction of the change in the amount of failure before and after the trip of the circuit breaker of the fault line is equal to the change of the fault amount before and after the circuit breaker trip of the trip line. The application of the two features makes the backup protection method highly sensitive and highly reliable.
本发明提出的后备保护动作判据可以自动把非故障线路的不平衡电流和干扰信号变为制动量，提高判断结果的可靠性。The backup protection action criterion proposed by the invention can automatically change the unbalanced current and the interference signal of the non-faulty line into the braking amount, thereby improving the reliability of the judgment result.
本发明提出的具有后备功能的接地故障选线方法，如果主保护误动作，后备保护能很快地跳开故障线路。主保护与后备保护的动作时间之和，再加上两条线路断路器跳闸时间之和，不会超过100毫秒。According to the ground fault line selection method with backup function proposed by the present invention, if the main protection malfunctions, the backup protection can quickly jump off the faulty line. The sum of the action time of the primary protection and the backup protection, plus the sum of the trip times of the two line breakers, does not exceed 100 milliseconds.
本发明可用现有技术设计制造，完全可以实现，有广阔应用前景。The invention can be designed and manufactured by using the prior art, can be completely realized, and has broad application prospects.
附图说明DRAWINGS
构成本发明的一部分的说明书附图用来提供对本发明的进一步理解，本发明的示意性实施例及其说明用于解释本发明，并不构成对本发明的不当限定。The accompanying drawings, which are incorporated in the claims of the claims
图1为小电流接地电力***分布式故障选线***示意图。Figure 1 is a schematic diagram of a distributed fault line selection system for a small current grounded power system.
图2为小电流接地电力***集中式故障选线***示意图。Figure 2 is a schematic diagram of a centralized fault line selection system for a small current grounded power system.
具体实施方式：Detailed ways:
下面结合附图与实施例对本发明作进一步说明。The invention will be further described below in conjunction with the drawings and embodiments.
应该指出，以下详细说明都是例示性的，旨在对本发明提供进一步的说明。除非另有指明，本文使用的所有技术和科学术语具有与本发明所属技术领域的普通技术人员通常理解的相同含义。It should be noted that the following detailed description is illustrative and is intended to provide a further description of the invention. All technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise indicated.
需要注意的是，这里所使用的术语仅是为了描述具体实施方式，而非意图 限制根据本发明的示例性实施方式。如在这里所使用的，除非上下文另外明确指出，否则单数形式也意图包括复数形式，此外，还应当理解的是，当在本说明书中使用术语“包含”和/或“包括”时，其指明存在特征、步骤、操作、器件、组件和/或它们的组合。It is to be noted that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to limit the exemplary embodiments of the invention. As used herein, the singular " " " " " " There are features, steps, operations, devices, components, and/or combinations thereof.
正如背景技术所介绍的，现有技术中存在小电流接地故障选线判据，最高正确动作率只有99％，且没有后备保护的不足，为了解决如上的技术问题，本发明提出了一种具有后备功能的小电流接地接地故障选线方法，提高小电流接地故障选线装置的正确动作率。As described in the background art, there is a small current ground fault line selection criterion in the prior art, the highest correct action rate is only 99%, and there is no shortage of backup protection. In order to solve the above technical problem, the present invention proposes a The small current grounding fault line selection method of the backup function improves the correct operation rate of the small current ground fault line selection device.
本发明的一种典型实施例，如图1所示，具有后备功能的小电流接地***分布式故障选线***，电源E给母线M送电。假设母线M连接有N条供电线路，N＝6。六条线路分别是L1、L2、L3、L4、L5、L6。每条线路各自设置一套小电流接地故障选线装置，分别是BH1、BH2、BH3、BH4、BH5、BH6。母线电压互感器TV的零序电压
Figure PCTCN2018094603-appb-000001
分别输入装置BH1、BH2、BH3、BH4、BH5、BH6。六条供电线路的电流互感器TA1、TA2、TA3、TA4、TA5、TA6的零序电流
Figure PCTCN2018094603-appb-000002
(i＝1，2，3，4，5，6)分别输入装置BH1、BH2、BH3、BH4、BH5、BH6。各条线路所属的装置没有获得其他线路的零序电流。 An exemplary embodiment of the present invention, as shown in FIG. 1, is a distributed fault line selection system for a small current grounding system having a backup function, and the power source E supplies power to the bus M. Assume that the bus M is connected to N power supply lines, N=6. The six lines are L1, L2, L3, L4, L5, and L6. Each line is provided with a set of small current ground fault line selection devices, namely BH1, BH2, BH3, BH4, BH5, BH6. Zero-sequence voltage of bus voltage transformer TV
Figure PCTCN2018094603-appb-000001
Input devices BH1, BH2, BH3, BH4, BH5, and BH6, respectively. Zero-sequence current of current transformers TA1, TA2, TA3, TA4, TA5, TA6 of six power supply lines
Figure PCTCN2018094603-appb-000002
(i = 1, 2, 3, 4, 5, 6) are input to the devices BH1, BH2, BH3, BH4, BH5, and BH6, respectively. The devices to which each line belongs do not receive the zero sequence current of other lines.
当小电流接地故障选线装置从电压互感器的输入信息中判断出电力***发生接地故障时，开始选线过程。习惯上，把分布式小电流接地故障选线装置称为保护装置。When the small current ground fault line selection device determines that the power system has a ground fault from the input information of the voltage transformer, the line selection process begins. It is customary to refer to a distributed small current ground fault line selection device as a protection device.
本发明提出的具有后备功能的小电流接地故障选线方法，需要借用原有的某种小电流接地故障选线方法，原有的小电流接地故障选线方法与装置称为主保护。主保护执行第一次故障选线任务。如果主保护已经正确选择出故障线路。 故障线路跳闸后，故障量消失，小电流接地故障选线装置整组复归，任务完成。如果主保护选线错误，误跳开非故障线路断路器后，电力***中的故障量仍然存在。小电流接地故障选线装置自动投入后备功能，执行第二次选线，跳开故障线路。后备功能也可称为后备保护。The method for selecting a small current ground fault with the backup function proposed by the invention needs to borrow the original small current ground fault line selection method, and the original small current ground fault line selection method and device are called main protection. The primary protection performs the first fault line selection task. If the primary protection has correctly selected the faulty line. After the faulty line trips, the fault quantity disappears, and the small current ground fault line selection device is reset and the task is completed. If the main protection line selection is incorrect and the non-fault line breaker is accidentally tripped, the amount of fault in the power system still exists. The small current ground fault line selection device automatically inputs the backup function, performs the second line selection, and trips the fault line. The fallback feature can also be called backup protection.
主保护的小电流接地故障选线方法，可利用现有的方法。不再累赘。The main protection method for small current ground faults can be used by existing methods. No longer tired.
本发明的后备保护应用“真实故障线路的断路器跳闸前后的故障量变化比较大，大于其他非故障线路的断路器跳闸前后的故障量变化”这一特征，还应用“真实故障线路的断路器跳闸前后的故障量变化的反方向等于跳闸线路的断路器跳闸前后的故障量变化”这一特征。两项特征的应用，使后备保护方法有很高的灵敏度，且有很高的可靠性。The backup protection application of the invention applies the feature that the failure amount of the circuit breaker before and after the trip of the real fault line is relatively large, which is larger than the fault amount before and after the trip of the circuit breaker of the other non-fault line, and the circuit breaker of the real fault line is also applied. The reverse direction of the change in the amount of failure before and after the trip is equal to the change in the amount of failure before and after the trip of the trip circuit of the trip line. The application of the two features makes the backup protection method highly sensitive and highly reliable.
所述故障量可以是工频的零序分量，可以是高次的谐波分量，可以是含有高频的零模分量，可以是某一频谱区段的零模分量，或其他故障特征量。The fault quantity may be a zero sequence component of the power frequency, may be a high order harmonic component, may be a zero mode component containing a high frequency, may be a zero mode component of a certain spectrum section, or other fault feature quantity.
例如1：故障量i CH(t)取工频零序电流
Figure PCTCN2018094603-appb-000003
表示线路在断路器跳闸前的零序电流相量，
Figure PCTCN2018094603-appb-000004
表示线路在断路器跳闸后的零序电流相量；则故障量在断路器跳闸前后的变化是
Figure PCTCN2018094603-appb-000005
第i条线路的断路器跳闸之前的故障量与断路器跳闸之后的故障量之差
Figure PCTCN2018094603-appb-000006
i＝1，2，3、、、N。跳闸线路的断路器跳闸之前的故障量与断路器跳闸之后的故障量之差
Figure PCTCN2018094603-appb-000007
如果第i条线路是真实故障线路，真实故障线路的断路器跳闸之前的故障量与断路器跳闸之后的故障量之差的反方向等于跳闸线路的断路器跳闸之前的故障量与断路器跳闸之后的故障量之差，就是
Figure PCTCN2018094603-appb-000008
For example, 1: the fault amount i CH (t) takes the power frequency zero sequence current
Figure PCTCN2018094603-appb-000003
Indicates the zero-sequence current phasor of the line before the circuit breaker trips.
Figure PCTCN2018094603-appb-000004
Indicates the zero-sequence current phasor of the line after the circuit breaker trips; then the change in the amount of fault before and after the trip of the circuit breaker is
Figure PCTCN2018094603-appb-000005
The difference between the fault amount before the breaker of the i-th line trips and the fault amount after the breaker trips
Figure PCTCN2018094603-appb-000006
i=1, 2, 3, ,, N. The difference between the fault amount before the circuit breaker tripping of the trip line and the fault amount after the trip of the circuit breaker
Figure PCTCN2018094603-appb-000007
If the ith line is a true fault line, the reverse direction of the difference between the fault amount before the circuit breaker trip of the real fault line and the fault amount after the trip of the circuit breaker is equal to the fault amount before the circuit breaker trip of the trip line and after the trip of the circuit breaker The difference between the faults is
Figure PCTCN2018094603-appb-000008
例如2：故障量i CH(t)取周期函数信号i CH(t)，i CH(t-MT)表示线路在断路器跳闸前的周期函数信号，i CH(t)表示线路在断路器跳闸后的周期函数信号；其中： 断路器在0秒跳闸；M是整定值，取正整数；T是周期函数信号的周期。则故障量在断路器跳闸前后的扰动是Δi CH(t)＝i CH(t-MT)-i CH(t)。第i条线路的断路器跳闸之前的故障量与断路器跳闸之后的故障量之差Δi CH,i(t)＝i CH,i(t-MT)-i CH,i(t)，i＝1，2，3、、、N。跳闸线路的断路器跳闸之前的故障量与断路器跳闸之后的故障量之差Δi CH,g(t)＝i CH,g(t-MT)-i CH,g(t)＝i CH,g(t-MT)。如果第i条线路是真实故障线路，真实故障线路的断路器跳闸之前的故障量与断路器跳闸之后的故障量之差的反方向等于跳闸线路的断路器跳闸之前的故障量与断路器跳闸之后的故障量之差，就是-Δi CH,i(t)＝Δi CH,g(t)。 For example, 2: the fault amount i CH (t) takes the periodic function signal i CH (t), i CH (t-MT) represents the periodic function signal of the line before the circuit breaker trips, and i CH (t) indicates that the line trips at the circuit breaker The following periodic function signal; wherein: the circuit breaker trips at 0 seconds; M is a set value, taking a positive integer; T is the period of the periodic function signal. Then the disturbance before and after the circuit breaker trips is Δi CH (t)=i CH (t-MT)-i CH (t). The difference between the fault amount before the breaker of the i-th line trips and the fault amount after the breaker trips Δi CH,i (t)=i CH,i (t-MT)-i CH,i (t),i= 1,2,3,,,N. The difference between the fault amount before the circuit breaker tripping of the trip line and the fault amount after the breaker trips Δi CH,g (t)=i CH,g (t-MT)-i CH,g (t)=i CH,g (t-MT). If the ith line is a true fault line, the reverse direction of the difference between the fault amount before the circuit breaker trip of the real fault line and the fault amount after the trip of the circuit breaker is equal to the fault amount before the circuit breaker trip of the trip line and after the trip of the circuit breaker The difference between the fault amounts is -Δi CH,i (t)=Δi CH,g (t).
说明：本文所述故障量的绝对值的积分，这种量是工频相量时，该相量的绝对值的积分是工频相量的幅值；这种量是周期函数信号时，该函数信号的绝对值的积分是，函数取绝对值后在0至MT秒时间段的积分除以2Mπ。Description: The integral of the absolute value of the fault quantity described in this paper. When the quantity is a power frequency phasor, the integral of the absolute value of the phasor is the amplitude of the power frequency phasor; when the quantity is a periodic function signal, The integral of the absolute value of the function signal is the integral of the time period from 0 to MT seconds divided by 2Mπ after taking the absolute value.
例如3：第i条线路的断路器跳闸前后的故障量变化是
Figure PCTCN2018094603-appb-000009
的绝对值的积分是ΔI 0,i。 For example, 3: the change in the amount of failure before and after the circuit breaker of the i-th line is tripped is
Figure PCTCN2018094603-appb-000009
The integral of the absolute value is ΔI 0,i .
例如4：第i条线路的断路器跳闸前后的故障量变化是Δi CH,i(t)，Δi CH,i(t)的绝对值的积分是
Figure PCTCN2018094603-appb-000010
For example, 4: the change in the amount of failure before and after the circuit breaker trip of the ith line is Δi CH, i (t), the integral of the absolute value of Δi CH, i (t) is
Figure PCTCN2018094603-appb-000010
为叙述方便，故障量不论是为工频零序电流，还是周期函数信号，都表示为i CH(t)。断路器跳闸之前的故障量与断路器跳闸之后的故障量之差，都表示为Δi CH(t)。断路器跳闸之前的故障量与断路器跳闸之后的故障量之差的绝对值的积分，简述为断路器跳闸前后的故障量变化的绝对值的积分，都表示为ΔI CH。 For the convenience of description, the fault amount is expressed as i CH (t) whether it is a power frequency zero sequence current or a periodic function signal. The difference between the amount of fault before the breaker trips and the fault after the breaker trips is expressed as Δi CH (t). The integral of the absolute value of the difference between the fault amount before the circuit breaker trips and the fault amount after the circuit breaker trips is briefly expressed as the integral of the absolute value of the fault amount change before and after the circuit breaker trips, and is expressed as ΔI CH .
后备保护方法1：当ΔI CH≥(I set,1+k 1A)，则被保护线路是故障线路。其中： I set,1是被保护线路第一预设阈值；k 1是被保护线路第一比例系数，根据经验设置；A是被保护线路与不平衡ΔI CH成正比的量；ΔI CH是被保护线路的断路器跳闸前后的故障量变化的绝对值的积分。 Backup protection method 1: When ΔI CH ≥ (I set, 1 + k 1 A), the protected line is the faulty line. Where: I set, 1 is the first preset threshold of the protected line; k 1 is the first proportional coefficient of the protected line, set according to experience; A is the amount of the protected line proportional to the unbalanced ΔI CH ; ΔI CH is The integral of the absolute value of the change in the amount of failure before and after the trip of the circuit breaker of the protection line.
例如5：可以令
Figure PCTCN2018094603-appb-000011
For example 5: can make
Figure PCTCN2018094603-appb-000011
例如6：可以令
Figure PCTCN2018094603-appb-000012
For example, 6: can make
Figure PCTCN2018094603-appb-000012
例如7：可以令
Figure PCTCN2018094603-appb-000013
For example, 7: can make
Figure PCTCN2018094603-appb-000013
小电流接地***某条线路发生单相接地故障，非故障线路的故障量(例如：容性零序电流)从母线流入线路，再流入大地。大地不能储存电流，所有非故障线路流入大地的故障量，都从故障线路的故障点流入故障线路，从故障线路流回母线。如果主保护误跳闸，跳闸线路流入大地的故障量就切断了。跳闸线路故障量的切断，不会影响跳闸线路以外的非故障线路的故障量，这些非故障线路流入大地的故障量在断路器跳闸之前与跳闸之后保持不变。跳闸线路故障量的切断，会影响真实故障线路的故障量，真实故障线路的故障量在断路器跳闸前后将发生变化，真实故障线路的故障量的变化等于跳闸线路的故障量的变化，但变化方向正好相反。跳闸线路切断的故障量越大，真实故障线路故障量的变化越大。主保护的故障选线方法，一般都是选择故障量较大的线路跳闸，所以，如果主保护误动作，线路断路器跳闸后，真实故障线路故障量的变化是比较大的。合理设置第一预设阈值I set,1，第一比例系数k 1；可以保证ΔI CH≥(I set,1+k 1A)。 A single-phase ground fault occurs in one line of a small current grounding system. The fault quantity of a non-fault line (for example, capacitive zero-sequence current) flows from the bus line to the line and then flows into the earth. The earth cannot store current, and the fault amount of all non-faulty lines flowing into the earth flows into the fault line from the fault point of the fault line and flows back to the bus line from the fault line. If the main protection trips by mistake, the amount of fault that the trip line flows into the earth is cut off. The disconnection of the trip line fault amount does not affect the fault amount of the non-fault line outside the trip line. The fault amount of these non-fault lines flowing into the earth remains unchanged before the trip of the circuit breaker and after the trip. The disconnection of the fault line of the trip line will affect the fault quantity of the real fault line. The fault quantity of the real fault line will change before and after the circuit breaker trips. The change of the fault quantity of the real fault line is equal to the change of the fault quantity of the trip line, but the change The direction is just the opposite. The greater the amount of faults in the trip line disconnection, the greater the change in the true fault line fault amount. The fault line selection method of the main protection is generally to select the line with a large fault to trip. Therefore, if the main protection fails, the fault of the real fault line is relatively large after the line breaker trips. The first preset threshold I set,1 and the first proportional coefficient k 1 are set reasonably; ΔI CH ≥(I set,1 +k 1 A) can be guaranteed.
理论上，在断路器跳闸前后，跳闸线路以外的非故障线路的故障量的变化的绝对值的积分等于零，实践中并不等于零。该不等于零的故障量的变化的绝 对值的积分称为不平衡ΔI CH。不平衡ΔI CH的大小与某种量成正比，取与不平衡ΔI CH成正比的某种量乘以第一比例系数k 1后作为制动量，可提高动作判据的灵敏度和可靠性。可以看出，后备保护方法1动作判据的制动量(I set,1+k 1A)不是固定的，而是具有自适应调节功能。根据电力***实际工作状态，自动调节动作判据中的制动量，不平衡ΔI CH大，制动作用大；不平衡ΔI CH小，制动作用小。这样，故障选线动作判据不但灵敏度高，且有较高可靠性。 Theoretically, the integral of the absolute value of the change in the amount of failure of the non-faulty line outside the trip line is equal to zero before and after the circuit breaker trips, and is not equal to zero in practice. The integral of the absolute value of the change in the amount of failure not equal to zero is called the imbalance ΔI CH . Is proportional to the size of the imbalance ΔI CH certain amount, a certain amount of unbalance ΔI CH proportional by a first proportionality factor k as the braking amount, can improve after the operation Criterion 1 sensitivity and reliability. It can be seen that the braking amount (I set, 1 + k 1 A) of the action criterion of the backup protection method 1 is not fixed, but has an adaptive adjustment function. According to the actual working state of the power system, the braking amount in the action criterion is automatically adjusted, the imbalance ΔI CH is large, the braking effect is large; the unbalance ΔI CH is small, and the braking effect is small. In this way, the fault line selection action criterion is not only highly sensitive, but also has high reliability.
因此，本发明提出的后备保护方法的选线灵敏度较高。Therefore, the line selection sensitivity of the backup protection method proposed by the present invention is high.
如果母线故障而产生的主保护误动作，所有各条线路的断路器跳闸前后的故障量变化的绝对值的积分都具有非故障线路的特点，所以，母线发生的接地故障，后备保护方法1不会误动作。If the main protection fault occurs due to the bus fault, the integral of the absolute value of the fault change before and after the circuit breaker trips of all the lines has the characteristics of the non-fault line. Therefore, the ground fault of the bus line, the backup protection method 1 does not Will malfunction.
本发明的另一种典型实施例，如图2所示，具有后备功能的小电流接地***集中式故障选线***，电源E给母线M送电。假设母线M连接有N条供电线路，N＝6。六条线路分别是L1、L2、L3、L4、L5、L6。母线电压互感器TV的零序电压
Figure PCTCN2018094603-appb-000014
输入一套小电流接地故障选线装置GZXX；6条供电线路的电流互感器TA1、TA2、TA3、TA4、TA5、TA6的零序电流
Figure PCTCN2018094603-appb-000015
(i＝1，2，3，4，5，6)分别输入装置GZXX。 Another exemplary embodiment of the present invention, as shown in FIG. 2, has a backup function of a small current grounding system centralized fault line selection system, and a power source E supplies power to the bus line M. Assume that the bus M is connected to N power supply lines, N=6. The six lines are L1, L2, L3, L4, L5, and L6. Zero-sequence voltage of bus voltage transformer TV
Figure PCTCN2018094603-appb-000014
Input a set of small current ground fault line selection device GZXX; zero current of current transformers TA1, TA2, TA3, TA4, TA5, TA6 of 6 power supply lines
Figure PCTCN2018094603-appb-000015
(i = 1, 2, 3, 4, 5, 6) are input to the device GZXX, respectively.
由于集中式故障选线***所获得的信息包含了分布式故障选线***的全部信息，所以，分布式故障选线***所有方法都可以移植到集中式故障选线***中。由于集中式故障选线***把所有信息都集中到一个装置里，建立了所有线路故障信息的相互沟通，所以，集中式故障选线***方法可以比分布式故障选线***的方法更多样。Since the information obtained by the centralized fault line selection system contains all the information of the distributed fault line selection system, all methods of the distributed fault line selection system can be transplanted into the centralized fault line selection system. Since the centralized fault line selection system concentrates all information into one device and establishes mutual communication of all line fault information, the centralized fault line selection system method can be more diverse than the distributed fault line selection system.
后备保护方法2：当ΔI CH,i＞(I set,2，i+k 2,i|ΔI CH,i-ΔI CH,g|),则第i条线路是故 障线路。其中：I set,2,i是第i条线路的第二预设阈值；k 2,i是第i条线路的第二比例系数，建议取1～20；ΔI CH,g是跳闸线路的断路器跳闸前后的故障量变化的绝对值的积分；ΔI CH，i是第i条线路的断路器跳闸前后的故障量变化的绝对值的积分。 Backup protection method 2: When ΔI CH,i >(I set,2,i +k 2,i |ΔI CH,i -ΔI CH,g |), the ith line is the fault line. Where: I set, 2, i is the second preset threshold of the ith line; k 2, i is the second proportional coefficient of the ith line, and it is recommended to take 1 to 20; ΔI CH, g is the open circuit of the trip line The integral of the absolute value of the fault amount change before and after the trip; ΔI CH,i is the integral of the absolute value of the fault amount change before and after the circuit breaker trip of the ith line.
主保护误跳闸后，非故障线路的断路器跳闸前后的故障量变化的绝对值的积分接近零，所以，非故障线路的后备保护方法2的动作判据的动作量ΔI CH,i接近零。跳闸线路的断路器跳闸前后的故障量变化的绝对值的积分是ΔI CH,g，所以，非故障线路的后备保护方法2的动作判据的制动量是(I set,2，i+k 2,i|ΔI CH,g|)，比较大。非故障线路的后备保护方法2可靠不动作。 After the main protection is accidentally tripped, the integral of the absolute value of the failure amount change before and after the circuit breaker trip of the non-faulty line approaches zero, so the operation amount ΔI CH,i of the operation criterion of the backup protection method 2 of the non-fault line approaches zero. The integral of the absolute value of the failure amount change before and after the circuit breaker trip of the trip line is ΔI CH,g , so the braking amount of the operation criterion of the backup protection method 2 of the non-fault line is (I set, 2, i + k 2,i |ΔI CH,g |), is relatively large. The backup protection method 2 of the non-faulty line does not work reliably.
主保护误跳闸后，真实故障线路的断路器跳闸前后的故障量变化的绝对值的积分等于跳闸线路的断路器跳闸前后的故障量变化的绝对值的积分ΔI CH,g，所以，真实故障线路的后备保护方法2的动作判据的动作量ΔI CH,i＝ΔI CH,g,比较大。真实故障线路的后备保护方法2的动作判据的制动量是I set,2，i。合理设置I set,2，i，真实故障线路的后备保护方法2灵敏动作。 After the main protection is accidentally tripped, the integral of the absolute value of the fault quantity change before and after the circuit breaker trip of the real fault line is equal to the integral ΔI CH,g of the absolute value of the fault quantity change before and after the circuit breaker trip of the trip line, so the true fault line The operation amount ΔI CH,i =ΔI CH,g of the operation criterion of the backup protection method 2 is relatively large. The braking amount of the action criterion of the backup protection method 2 of the real fault line is I set, 2, i . Reasonably set I set, 2, i , the backup protection method of the real fault line 2 sensitive action.
后备保护方法3：当ΔI CH,i＞(I set,2，i+k 2,iΣI i),则第i条线路是故障线路。其中：I set,2,i是第i条线路的第二预设阈值；k 2,i是第i条线路的第二比例系数，建议取1～20；ΣI i是第i条线路的断路器跳闸前后的故障量变化与跳闸线路的断路器跳闸前后的故障量变化之和的绝对值的积分，即Σi i(t)＝Δi CH,i(t)+Δi CH,g(t)；ΔI CH，i是第i条线路的断路器跳闸前后的故障量变化的绝对值的积分。 Backup protection method 3: When ΔI CH,i >(I set,2,i +k 2,i ΣI i ), the ith line is the faulty line. Where: I set, 2, i is the second preset threshold of the ith line; k 2, i is the second proportional coefficient of the ith line, and it is recommended to take 1 to 20; ΣI i is the open circuit of the ith line The integral of the absolute value of the sum of the fault amount before and after the trip and the change of the fault amount before and after the breaker trip of the trip line, ie Σi i (t)=Δi CH,i (t)+Δi CH,g (t); ΔI CH,i is the integral of the absolute value of the change in the amount of failure before and after the circuit breaker trip of the i-th line.
可以看出，后备保护方法2应用了“真实故障线路的断路器跳闸前后的故障量变化的绝对值积分等于跳闸线路的断路器跳闸前后的故障量变化的绝对值积分”这条特征，取两个积分相减的差再取绝对值作为制动量，应用了两个函数积分后的特点。后备保护方法3则应用“真实故障线路的断路器跳闸前后的 故障量变化的反方向等于跳闸线路的断路器跳闸前后的故障量变化”这条特征。两个函数没有被积分之前，两个函数方向相反，这样两个函数相加，实际是相减。不但应用了两个函数的积分性质，两个函数波形变化细节也得到应用。后备保护方法3特别适合应用在非故障线路的断路器跳闸前后的故障量变化不接近零，不平衡电流比较大、干扰信号比较强的场合。后备保护方法3可以自动把非故障线路的不平衡电流和干扰信号变为制动量，提高判断结果的可靠性。It can be seen that the backup protection method 2 applies the feature that the absolute value integral of the fault quantity change before and after the circuit breaker trip of the real fault line is equal to the absolute value integral of the fault quantity change before and after the circuit breaker trip of the trip line, taking two The difference between the integral subtraction and the absolute value is taken as the braking amount, and the characteristics after the integration of the two functions are applied. The backup protection method 3 applies the feature that the reverse direction of the fault quantity change before and after the circuit breaker trips of the real fault line is equal to the fault quantity change before and after the circuit breaker trip of the trip line. Before the two functions are integrated, the two functions are in the opposite direction, so that the two functions are added together and are actually subtracted. Not only the integration properties of the two functions are applied, but also the details of the waveform changes of the two functions are applied. The backup protection method 3 is particularly suitable for applications where the fault quantity change before and after the circuit breaker trip of the non-faulty line is not close to zero, the unbalanced current is relatively large, and the interference signal is relatively strong. The backup protection method 3 can automatically change the unbalanced current and the interference signal of the non-faulty line into the braking amount, thereby improving the reliability of the judgment result.
如果母线故障而产生的主保护误动作，所有线路的断路器跳闸前后的故障量变化的绝对值的积分都具有非故障线路的特点，所以，母线发生的接地故障，后备保护方法2，或方法3不会误动作。If the main protection fault caused by the bus fault occurs, the integral of the absolute value of the fault change before and after the circuit breaker trips of all the lines has the characteristics of the non-fault line, so the ground fault occurred by the bus, the backup protection method 2, or the method 3 will not malfunction.
后备保护方法4：除去跳闸线路，断路器跳闸前后的故障量变化的绝对值的积分ΔI CH,i最大的线路是待定故障线路。 Backup protection method 4: In addition to the trip line, the integral of the absolute value of the fault quantity change before and after the circuit breaker trips ΔI CH, i the maximum line is the pending fault line.
后备保护方法5：除去跳闸线路，线路的断路器跳闸前后的故障量变化的绝对值的积分减去跳闸线路的断路器跳闸前后的故障量变化的绝对值的积分之差的绝对值|ΔI CH,i-ΔI CH,g|最小的线路是待定故障线路。 Backup protection method 5: In addition to the trip line, the integral value of the absolute value of the fault amount change before and after the trip of the circuit breaker is subtracted from the absolute value of the integral value of the absolute value of the fault amount change before and after the circuit breaker trip of the trip line | ΔI CH , i -ΔI CH,g | The smallest line is the pending fault line.
如果接地故障发生在某条线路，后备保护方法4和方法5判断的结果就是故障线路。如果接地故障发生在母线，后备保护方法4和方法5判断的结果就是错误的。由于不知道接地故障是否发生在线路，所以，后备保护方法4和方法5判断的结果不能最后确定，只能待定。后备保护方法4和方法5不能单独应用，必须与后备保护方法1，或方法2，或方法3配合应用，用以进一步提高后备保护方法1，或方法2，或方法3的可靠性。If a ground fault occurs on a certain line, the result of the backup protection method 4 and method 5 is the fault line. If the ground fault occurs on the bus, the result of the backup protection method 4 and method 5 is wrong. Since it is not known whether the ground fault occurs on the line, the results of the backup protection method 4 and method 5 cannot be finalized and can only be determined. The backup protection method 4 and the method 5 cannot be applied separately, and must be applied together with the backup protection method 1, or the method 2, or the method 3 to further improve the reliability of the backup protection method 1, or the method 2, or the method 3.
需要指出，主保护跳闸后，如果电压故障量没有消失，则说明故障选线错误。后备保护可快速投入，不必等待误跳闸线路的重合闸完成以后再投入后备 保护。后备保护选出故障线路后，可快速跳闸。这样，即使是主保护误动作，后备保护也能很快地跳开故障线路。主保护与后备保护的动作时间之和，再加上两条线路断路器跳闸时间之和，不会超过100毫秒。It should be pointed out that if the voltage fault does not disappear after the main protection trips, it indicates that the fault line selection is wrong. The backup protection can be quickly put into operation without having to wait for the reclosing of the false trip line to complete the backup protection. After the backup protection selects the faulty line, it can quickly trip. In this way, even if the main protection malfunctions, the backup protection can quickly trip the faulty line. The sum of the action time of the primary protection and the backup protection, plus the sum of the trip times of the two line breakers, does not exceed 100 milliseconds.
本发明的一种具有后备功能的小电流接地故障选线方法，完全可以实现，有广阔应用前景。The method for selecting a small current ground fault with a backup function of the invention can be completely realized, and has broad application prospects.
以上所述仅为本发明的优选实施例而已，并不用于限制本发明，对于本领域的技术人员来说，本发明可以有各种更改和变化。凡在本发明的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本发明的保护范围之内。The above description is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.
上述虽然结合附图对本发明的具体实施方式进行了描述，但并非对本发明保护范围的限制，所属领域技术人员应该明白，在本发明的技术方案的基础上，本领域技术人员不需要付出创造性劳动即可做出的各种修改或变形仍在本发明的保护范围以内。The above description of the specific embodiments of the present invention has been described with reference to the accompanying drawings, but it is not intended to limit the scope of the present invention. Those skilled in the art should understand that the skilled in the art does not require the creative work on the basis of the technical solutions of the present invention. Various modifications or variations that can be made are still within the scope of the invention.

Claims (10)

  1. 一种具有后备功能的小电流接地故障选线***，其特征是：包括主保护***和至少一套后备保护***，当主保护***故障时，由后备保护***计算各条线路的断路器跳闸前后的故障量变化的绝对值的积分，并将该故障量变化作为动作判据，判断跳闸线路，实现灵敏动作。A small current ground fault line selection system with backup function, comprising: a primary protection system and at least one backup protection system, when the primary protection system fails, the backup protection system calculates the circuit breaker before and after the trip of each line The integral of the absolute value of the fault amount change, and the fault amount change is used as the action criterion to determine the trip line and achieve a sensitive action.
  2. 如权利要求1所述的一种具有后备功能的小电流接地故障选线***，其特征是：利用真实故障线路的断路器跳闸前后的故障量变化量大于其他非故障线路的断路器跳闸前后的故障量变化量或/和真实故障线路的断路器跳闸前后的故障量变化的反方向等于跳闸线路的断路器跳闸前后的故障量变化为动作判据，判断后备保护跳闸线路。A small current ground fault line selection system with backup function according to claim 1, wherein the fault amount before and after the circuit breaker tripping using the real fault line is greater than that before and after the trip of the other non-fault line circuit breaker. The amount of change in the amount of fault or / and the reverse direction of the change in the amount of fault before and after the circuit breaker trip of the real fault line is equal to the change in the amount of fault before and after the trip of the circuit breaker of the trip line is the action criterion, and the backup protection trip line is determined.
  3. 一种具有后备功能的小电流接地故障选线方法，其特征是：主保护***执行故障选线任务，如果主保护***正确选择出故障线路，跳开选择的故障线路，任务完成；A small current ground fault line selection method with backup function, characterized in that: the primary protection system performs a fault line selection task, and if the primary protection system correctly selects the fault line, the selected fault line is tripped, and the task is completed;
    当主保护***故障时，由后备保护***计算各条线路的断路器跳闸前后的故障量变化的绝对值的积分，并将该故障量变化作为动作判据，判断跳闸线路，实现灵敏动作。When the primary protection system fails, the backup protection system calculates the integral of the absolute value of the fault change before and after the circuit breaker trips of each line, and uses the fault quantity change as an action criterion to determine the trip line and achieve a sensitive action.
  4. 如权利要求3所述的一种具有后备功能的小电流接地故障选线方法，其特征是：计算每条被保护线路的断路器跳闸前后的故障量变化的绝对值的积分值，积分值大于制动量的对应的线路是故障线路，所述制动量为对应线路的预设整定值和一个与故障特征不平衡量成比例的调整项之和。A small current ground fault line selection method with backup function according to claim 3, wherein: an integral value of an absolute value of a fault amount change before and after a circuit breaker trip of each protected line is calculated, and the integral value is greater than The corresponding line of the braking amount is the fault line, and the braking amount is the sum of the preset setting value of the corresponding line and an adjustment item proportional to the amount of the fault characteristic imbalance.
  5. 如权利要求4所述的一种具有后备功能的小电流接地故障选线方法，其特征是：调整项是母线零序电压幅值，或被保护线路零序电流幅值，或被保护线路故障量的绝对值的积分。A small current ground fault line selection method with backup function according to claim 4, wherein the adjustment item is a bus zero sequence voltage amplitude, or a protected line zero sequence current amplitude, or a protected line fault. The integral of the absolute value of the quantity.
  6. 如权利要求5所述的一种具有后备功能的小电流接地故障选线方法，其特征是：调整项的值为对应被保护线路的断路器跳闸前后的故障量变化的绝对值的积分与跳闸线路的断路器跳闸前后的故障量变化的绝对值的积分差值的绝对值。A small current ground fault line selection method with backup function according to claim 5, wherein the value of the adjustment item is an integral and trip of the absolute value of the fault amount change before and after the trip of the circuit breaker corresponding to the protected line. The absolute value of the integral difference of the absolute value of the fault amount change before and after the circuit breaker trips.
  7. 如权利要求5所述的一种具有后备功能的小电流接地故障选线方法，其特征是：调整项的值为对应被保护线路的断路器跳闸前后的故障量变化与跳闸线路的断路器跳闸前后的故障量变化之和的绝对值的积分。A small current ground fault line selection method with backup function according to claim 5, wherein the value of the adjustment item is a fault amount change before and after the trip of the circuit breaker corresponding to the protected line and the circuit breaker trip of the trip line. The integral of the absolute value of the sum of the changes in the amount of failure before and after.
  8. 一种具有后备功能的小电流接地故障选线方法，适用于集中式故障选线***，其特征是：当有被保护线路同时满足以下两条判据时，确定该被保护线路为故障线路：A small current ground fault line selection method with backup function is suitable for a centralized fault line selection system, and is characterized in that: when a protected line meets the following two criteria at the same time, it is determined that the protected line is a fault line:
    (3)计算被保护线路的断路器跳闸前后的故障量变化的绝对值的积分值大于制动量，制动量为对应线路的预设整定值和一个与故障特征不平衡量成比例的调整项之和；(3) Calculate the integral value of the absolute value of the fault amount change before and after the trip of the circuit breaker of the protected line is greater than the braking amount, the braking amount is the preset setting value of the corresponding line and an adjustment item proportional to the unbalanced amount of the fault characteristic Sum;
    (4)除去跳闸线路，被保护线路的断路器跳闸前后的故障量变化的绝对值的积分最大。(4) Except for the trip line, the integral of the absolute value of the change in the amount of failure before and after the circuit breaker of the protected line is tripped is the largest.
  9. 一种具有后备功能的小电流接地故障选线方法，适用于集中式故障选线***，其特征是：当有被保护线路同时满足以下两条判据时，确定该被保护线路为故障线路：A small current ground fault line selection method with backup function is suitable for a centralized fault line selection system, and is characterized in that: when a protected line meets the following two criteria at the same time, it is determined that the protected line is a fault line:
    (1)除去跳闸线路，线路的断路器跳闸前后的故障量变化的绝对值的积分减去跳闸线路的断路器跳闸前后的故障量变化的绝对值的积分之差的绝对值最小；(1) In addition to the trip line, the integral value of the absolute value of the change in the amount of failure before and after the trip of the circuit breaker of the line is subtracted from the absolute value of the integral of the absolute value of the change in the amount of the fault before and after the circuit breaker trip of the trip line is minimum;
    (2)被保护线路的断路器跳闸前后的故障量变化的绝对值的积分值大于制动量，制动量为对应线路的预设整定值和一个与故障特征不平衡量成比例的调整项之和。(2) The integral value of the absolute value of the fault amount change before and after the trip of the circuit breaker of the protected line is greater than the braking amount, and the braking amount is the preset setting value of the corresponding line and an adjustment item proportional to the unbalance amount of the fault characteristic. with.
  10. 如权利要求3所述的一种具有后备功能的小电流接地故障选线方法，其特征是：当主保护***内跳闸后，如果电压故障量没有消失，则说明故障选线错误，后备保护***即可投入，不必等待误跳闸线路的重合闸完成。The method for selecting a small current ground fault with a backup function according to claim 3 is characterized in that: after the trip in the main protection system, if the voltage fault amount does not disappear, the fault line selection error is performed, and the backup protection system is It can be put in without waiting for the reclosing of the false trip line to be completed.
PCT/CN2018/094603 2017-09-06 2018-07-05 Small-current grounding fault line selection system and method having backup function WO2019047610A1 (en)

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