A method for identifying line breakage fault of medium and high voltage distribution network

Abstract

The application discloses a kind of high-voltage distribution network line breakage fault identification methods, obtain distribution network bus interval current data, distribution network bus current data, distribution network bus voltage data, distribution network bus interval circuit breaker position;Judge whether it satisfies line single-phase breakage fault condition or line multiple-phase breakage fault condition;When determining that single-phase breakage fault or multiple-phase breakage fault occurs in certain bus interval of distribution network, it is determined by pre-setting mode, and warning signal is sent or switch of breakage fault interval is tripped after time delay.The high-voltage distribution network line breakage fault identification method provided by the application sends corresponding prompt signal when identifying line breakage, prompts operating personnel to eliminate fault in time, avoids that unbalanced load and overvoltage and other working conditions caused by open-phase operation endanger power grid operation safety.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of high-voltage distribution network line breakage fault identification method, belong to the technical field of power system automation. BACKGROUND

[0002] Distribution network line breakage fault is one of common faults of distribution network, after distribution line breakage fault occurs, it will directly cause part of user power failure, and the asymmetric voltage generated by long time breakage operation is easy to cause the damage of electric equipment, and the overvoltage generated by neutral point deviation can even cause transformer burnout. Since distribution network lacks relay protection device for directly monitoring breakage fault, after breakage fault occurs, it is often necessary to feed back the fault information to power grid operation department by user, or to select line and trip by protection device after breakage phase occurs grounding fault, and the fault can be eliminated after a long time.

[0003] For the line of high-voltage distribution network, since its voltage level is higher, and the power supply range is larger, if breakage fault occurs, the harm degree will be more serious.

[0004] Therefore, how to quickly and accurately identify breakage branch and eliminate fault in time is a technical problem that the person skilled in the art urgently needs to solve. SUMMARY

[0005] Purpose: in order to overcome the deficiencies in the prior art, the present application provides a kind of high-voltage distribution network line breakage fault identification method, for in high-voltage distribution network, based on the electrical quantity collected at 35kV or 10kV bus, according to the change of bus differential flow, zero sequence current of each interval on bus, negative sequence component in bus braking current and the change of bus zero sequence voltage, accurately identify the line where single-phase breakage occurs;According to the change of bus differential flow, bus braking current and switch position state, accurately identify the line where two-phase breakage or three-phase breakage occurs.

[0006] Technical scheme: in order to solve the above technical problems, the technical scheme adopted by the present application is:

[0007] A kind of high-voltage distribution network line breakage fault identification method, comprising the following steps:

[0008] Step 1: obtain distribution network bus interval current data, distribution network bus current data, distribution network bus voltage data, distribution network bus interval circuit breaker position.

[0009] Step 2: determine whether distribution network bus interval current data, distribution network bus current data, distribution network bus voltage data and bus interval circuit breaker position meet the condition of single-phase breakage fault or the condition of multi-phase breakage fault of line.

[0010] Step 3: When a single-phase or multi-phase line break fault occurs in a bus interval of the power distribution network, an alarm signal is sent or the switch of the line break fault interval is tripped after a predetermined delay.

[0011] As a preferred solution, the step 1 comprises:

[0012] Obtaining the current of the bus interval k of the power distribution network The negative sequence component of the current of the bus interval k and the zero sequence component The rated current In,k of the bus interval is a natural number.

[0013] Obtaining the differential current obtained by superimposing the currents of all access intervals of the bus of the power distribution network The braking current I obtained by superimposing the currents of all access intervals of the bus r The braking current negative sequence component I obtained by superimposing the negative sequence components of the currents of all access intervals of the bus r(2) .

[0014] Obtaining the bus voltage of the power distribution network The zero sequence component in the bus voltage

[0015] Obtaining the position of the circuit breaker of the bus interval of the power distribution network.

[0016] As a preferred solution, the step 2 of determining whether the current data of the bus interval of the power distribution network, the bus current data of the power distribution network, the bus voltage data of the power distribution network, and the position of the circuit breaker of the bus interval satisfy the single-phase line break fault condition of the line comprises:

[0017] When conditions (1), (2), (3), (4), (5), and (6) are met at the same time, and the meeting time t1s is met, it is determined that the interval k has a single-phase line break fault.

[0018] The condition (1) is: It is larger than the previous cycle and the change is greater than 0.5V. If the above characteristics are met for 3 consecutive sampling points, the meeting time of condition (1) can be extended by 3s.

[0019] The condition (2) is: r(2) It is larger than the previous cycle and the change is greater than I set1 , wherein I set1 is adjustable. If the above characteristics are met for 3 consecutive sampling points, the meeting time of condition (2) can be extended by 3s.

[0020] The condition (3) is: Less than 0.02In.

[0021] The condition (4): only one interval k has only one phase current less than 0.02In.

[0022] The condition (5): interval k Less than 0.02In.

[0023] The condition (6): interval k Greater than I set2 , wherein I set2 is adjustable.

[0024] As a preferred solution, t1=0.5s.

[0025] As a preferred solution, the value range of I set1 , I set2 is (0.05In-0.2In).

[0026] As a preferred solution, the step 2 determines whether the interval current data of the distribution network bus, the distribution network bus current data, the distribution network bus voltage data and the bus interval circuit breaker position meet the line multi-phase broken line fault condition, comprising:

[0027] When the condition (7), condition (8), condition (9), condition (10), condition (11), condition (12) are met at the same time, and t2s is met, it is determined that interval k has a multi-phase broken line fault.

[0028] The condition (7): Compared with the last cycle, any phase Decreases by more than 0.5V, and if the above characteristics are met for 3 consecutive sampling points, the meeting time of condition (7) can be extended by 3s.

[0029] The condition (8): at least two phases I r Decreases compared with the last cycle and the change is greater than I set3 , wherein I set3 is adjustable, and if the above characteristics are met for 3 consecutive sampling points, the meeting time of condition (8) can be extended by 3s.

[0030] The condition (9): Less than 0.02In.

[0031] The condition (10): only one interval k has at least two phase currents decreasing compared with the last cycle and the change is greater than I set4 , wherein I set4 is adjustable.

[0032] The condition (11): interval k, the phase with decreasing current, the decreased current is less than 0.02In.

[0033] The condition (12): interval k, the switch position does not change.

[0034] As a preferred solution, the t2 = 2s.

[0035] As a preferred solution, the I set3 , I set4 The value range of (0.05In-0.1In).

[0036] Beneficial effects: the method for identifying line breakage fault of medium and high voltage distribution network provided by the application collects multi-element information on the bus, adopts combination of single interval information and multi interval information, combination of steady state quantity information and change quantity information, effectively identifies single phase line breakage and multi phase line breakage fault of the line, when the line breakage is identified, corresponding prompt signal is sent, the operator is prompted to eliminate the fault in time, load imbalance and overvoltage and other working conditions caused by open phase operation are avoided, and the safety of power grid operation is ensured.

[0037] Compared with the prior art, the beneficial effects of the application are:

[0038] (1) combination of single interval information and multi interval information, combination of steady state quantity information and change quantity information, can identify single phase line breakage and multi phase line breakage and select the line breakage line, and the criterion has high accuracy.

[0039] (2) all intervals connected to the bus can be monitored at the same time, and the method can be self-adaptive when the number of bus connection intervals changes.

[0040] (3) for the identified line breakage line, multiple modes such as alarm or tripping can be set, effectively improving the safety and stability of power grid operation. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 It is a branch single phase line breakage identification flowchart.

[0042] Figure 2 It is a branch multi phase line breakage identification flowchart. DETAILED DESCRIPTION

[0043] The application will be further described below in combination with specific embodiments.

[0044] A method for identifying line breakage fault of medium and high voltage distribution network, according to the characteristics of 35kV or 10kV distribution network line breakage fault, single phase line breakage and multi phase line breakage of the line, the following identification method is proposed:

[0045] Let the number of bus connection intervals be n, In be the secondary rated current of the mutual inductor connected to the bus, is the current of interval k, The negative sequence component in the interval k current, The zero sequence component in the interval k current, The differential current obtained by superimposing the interval currents of all accesses to the busbar, r The braking current obtained by superimposing the interval currents of all accesses to the busbar, r(2) The braking current negative sequence component obtained by superimposing the negative sequence components of the interval currents of all accesses to the busbar, The busbar voltage, The zero sequence component in the busbar voltage. k and n are natural numbers.

[0046] As shown in Figure 1 For a single-phase broken line fault of the line, the following conditions are proposed:

[0047] Condition (1): Increases compared with the previous cycle and the change is greater than 0.5V. If the above characteristics are met for 3 consecutive sampling points, the meeting duration of condition (1) can be extended by 3s.

[0048] Condition (2): I r(2) Increases compared with the previous cycle and the change is greater than I set1 , wherein I set1 is adjustable, and the value range of I set1 is (0.05In-0.2In). If the above characteristics are met for 3 consecutive sampling points, the meeting duration of condition (2) can be extended by 3s.

[0049] Condition (3): Is less than 0.02In.

[0050] Condition (4): There is only one interval k, and only one-phase current is less than 0.02In.

[0051] Condition (5): The above interval k, Is less than 0.02In.

[0052] Condition (6): The above interval k, Is greater than I set2 , wherein I set2 is adjustable, and the value range of I set2 is (0.05In-0.2In).

[0053] When conditions (1), (2), (3), (4), (5), and (6) are met at the same time, and the meeting duration is 0.5s, it is determined that a single-phase broken line fault occurs in interval k.

[0054] As shown in Figure 2 For a multi-phase broken line fault of the line, the following conditions are proposed:

[0055] Condition (7): Increase compared with the last cycle or any phase Decrease compared with the last cycle, and the change is greater than 0.5V, if the above characteristics are met for 3 consecutive sampling points, the duration of condition (7) can be extended by 3s.

[0056] Condition (8): at least two phases I r Decrease compared with the last cycle and the change is greater than I set3 , wherein I set3 is adjustable, the value range of I set3 is (0.05In-0.1In), if the above characteristics are met for 3 consecutive sampling points, the duration of condition (8) can be extended by 3s.

[0057] Condition (9): Less than 0.02In.

[0058] Condition (10): there is only one interval k, at least two phase currents decrease compared with the last cycle and the change is greater than I set4 , wherein I set4 is adjustable, the value range of I set4 is (0.05In-0.1In).

[0059] Condition (11): in the above interval k, the phase with decreasing current, the decreased current is less than 0.02In.

[0060] Condition (12): in the above interval k, the switch position has not changed.

[0061] When conditions (7), (8), (9), (10), (11), and (12) are met simultaneously, and the duration is 2s, it is determined that the interval k has a multi-phase broken line fault.

[0062] When a single-phase or multi-phase broken line fault is determined in the interval k, it can be determined by pre-adjustment whether to issue an alarm signal or to delay and trip the switch of the broken line interval.

[0063] The above is only the preferred embodiment of the present application, it should be noted that for those skilled in the art, without departing from the principles of the present application, can make a number of improvements and refinements, these improvements and refinements should also be considered within the scope of the present application.

Claims

1. A method for identifying open-circuit faults in medium- and high-voltage distribution network lines, characterized in that: Includes the following steps: Step 1: Obtain the distribution network bus bay current data, distribution network bus voltage data, and the location of the distribution network bus bay circuit breaker; Step 2: Determine whether the distribution network bus bay current data, distribution network bus voltage data, and bus bay circuit breaker location meet the conditions for a single-phase open circuit fault or a multi-phase open circuit fault. Step 3: When it is determined that a single-phase or multi-phase open circuit fault has occurred in a bus bay of the distribution network, the alarm signal is issued or the switch of the open circuit fault bay is tripped after a delay through the pre-set method. Step 1 includes: Obtain the current of bus bay k in the distribution network Negative sequence component of current in bus spacing k and zero-order components The rated currents of the busbar bays, In, k, and n, are natural numbers. Obtain the differential current obtained by superimposing the currents of all connected bays of the distribution network bus. The braking current I obtained by superimposing the currents of all connected bays on the busbar r The negative sequence component of the braking current I is obtained by superimposing the negative sequence components of all connected interval currents of the busbar. r(2) ; Obtain the voltage of the distribution network bus Zero-sequence component in bus voltage Obtain the location of the busbar circuit breakers in the distribution network; Step 2 involves determining whether the distribution network busbar bay current data, distribution network busbar voltage data, and the location of the busbar bay circuit breaker meet the conditions for a single-phase open-circuit fault. This includes: If conditions (1), (2), (3), (4), (5), and (6) are met simultaneously for a duration of t1s, then a single-phase open circuit fault is determined to have occurred in interval k. The condition (1): Compared with the previous week, the value increases and the change is greater than 0.5V. If three consecutive sampling points meet the above characteristics, the duration of condition (1) can be extended by 3s. The condition (2): I r(2) Compared to the previous week's wave, it increased and the change was greater than I. set1 , where I set1 It can be adjusted. If three consecutive sampling points satisfy the above characteristics, the duration of satisfying condition (2) can be extended by 3 seconds. The condition (3): Less than 0.02In; The condition (4) is: there is one and only one interval k, and only one phase current is less than 0.02In; Condition (5): Interval Less than 0.02In; Condition (6): Interval Greater than I set2 , where I set2 Adjustable.

2. The method for identifying open circuit faults in medium and high voltage distribution network lines according to claim 1, characterized in that: The t1 = 0.5s.

3. The method for identifying open circuit faults in medium and high voltage distribution network lines according to claim 2, characterized in that: The I set1 I set2 The value range is 0.05In-0.2In.

4. The method for identifying open circuit faults in medium and high voltage distribution network lines according to claim 1, characterized in that: Step 2 involves determining whether the distribution network busbar bay current data, distribution network busbar voltage data, and the location of the busbar bay circuit breaker meet the conditions for a multi-phase line failure, including: When conditions (7), (8), (9), (10), (11), and (12) are met simultaneously for a duration of t2s, it is determined that a multi-phase open circuit fault has occurred in interval k. The condition (7): Compared to the previous week's wave, it increased or any phase Compared with the previous week, it decreases and the change is greater than 0.5V. If three consecutive sampling points meet the above characteristics, the duration of condition (7) can be extended by 3s. Condition (8): at least two phases I r Compared to the previous week's wave, it decreased and the change was greater than I. set3 , where I set3 It can be adjusted. If three consecutive sampling points satisfy the above characteristics, the duration of satisfying condition (8) can be extended by 3 seconds. The condition (9) is as follows: Less than 0.02In; The condition (10) is: there is one and only one interval k, and at least two phase currents decrease compared to the previous cycle and the change is greater than I. set4 , where I set4 Adjustable; The condition (11) is: at interval k, the phase with reduced current has a reduced current of less than 0.02In; Condition (12): Interval k, the switch position did not change.

5. The method for identifying open circuit faults in medium- and high-voltage distribution network lines according to claim 4, characterized in that: The given t2 = 2s.

6. The method for identifying open circuit faults in medium- and high-voltage distribution network lines according to claim 5, characterized in that: The I set3 I set4 The value range is 0.05In-0.1In.

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