CN-122017467-A - Line fault type identification method

CN122017467ACN 122017467 ACN122017467 ACN 122017467ACN-122017467-A

Abstract

The invention provides a line fault type identification method which comprises overload tripping, typical short circuit tripping and heavy load and large load input/long-distance short circuit tripping, wherein S1 is used for collecting and storing current waveform maximum absolute value data of 10 cycles before tripping, adjacent cycle current change slope K is calculated according to the formula of K= (I2-I1)/(t 2-t 1), and judging conditions are that a circuit breaker trips, and current change slope K of all adjacent waveforms is less than Kset1. The line fault type identification method provided by the invention can be used for rapidly identifying four tripping types of overload, typical short circuit, heavy load and heavy load input and long-distance short circuit, is free from manual trial feeding judgment, has high identification speed and high accuracy, can guide operation and maintenance personnel to rapidly treat, greatly shortens the power failure time and improves the power supply reliability of the low-voltage distribution network.

Inventors

CHEN ZHIFENG
LI YAN
XU GANG
CHEN LINGMIN
Ou Yujiang
YU ZIJIAN

Assignees

广东云舜综合能源科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260403

Claims (10)

1. A method for identifying a line fault type, comprising: overload tripping, typical short circuit tripping, and heavy load and large load input/long distance short circuit tripping; The tripping of the overload comprises the following steps: S1, collecting and storing current waveform maximum absolute value data of 10 cycles before tripping; S2, calculating the change slope K of adjacent cyclic current according to the formula of K= (I 2 −I 1 )/(t 2 −t 1 ); S3, judging the conditions that the circuit breaker trips, and the current change slope K of all adjacent waveforms is less than Kset1; s4, identifying a conclusion that overload causes overcurrent and causes overcurrent protection tripping of the circuit breaker is judged; The typical short circuit trip comprises the steps of: S1, collecting and storing current waveform maximum absolute value data of 10 cycles before tripping; S2, calculating the change slope K of adjacent cyclic current according to the formula of K= (I 2 −I 1 )/(t 2 −t 1 ); s3, judging the conditions that the circuit breaker trips, and the current change slope K of any adjacent waveform is larger than Kset2; s4, identifying a conclusion that the current mutation is caused by the short circuit fault, so that the overcurrent protection of the circuit breaker is tripped; the tripping of the heavy load and heavy load input/long-distance short circuit comprises the following steps: s1, collecting and storing current, voltage waveforms and phasor data of 10 cycles before tripping, and calculating the current change slope K of adjacent cycles; s2, slope preliminary screening, namely judging that Kset1< K < Kset2 is met, and entering an impedance angle precise distinguishing process. S3, calculating phasor; S4, judging the impedance angle.
2. The line fault type identification method according to claim 1, wherein Kset1 is a large load characteristic slope and Kset2 is a short circuit characteristic slope.
3. The line fault type identification method as claimed in claim 1, wherein the phasor calculation includes a heavy load input scenario including a fault current phasor Calculating the impedance angle phi=arg # ); Remote short-circuit scene fault current phasor Calculating the impedance angle phi=arg # )。
4. The line fault type identification method as claimed in claim 1, wherein the impedance angle determination includes a determination that a heavy load input trip is determined under heavy load if phi >45 °: fault deviation is detected; if phi <45 degrees, the fault deviation resistance is judged to be the tripping of the long-distance short-circuit fault.
5. The line fault type identification method according to claim 1, wherein the overload trip is performed by using low-voltage distribution network electric equipment, the low-voltage distribution network electric equipment comprises a power distribution cabinet body, a heat dissipation assembly, two moving assemblies and a protection assembly, the heat dissipation assembly is arranged on the back surface of the power distribution cabinet body, the two moving assemblies are respectively arranged on the upper side and the lower side of the back surface of the power distribution cabinet body, and the protection assembly is arranged between the two moving assemblies.
6. The line fault type identification method according to claim 5, wherein the heat dissipation assembly comprises a heat dissipation net, a plurality of positioning blocks, a plurality of positioning grooves and a plurality of bolts, the plurality of positioning blocks are respectively connected to the left side and the right side of the top and the bottom of the heat dissipation net, the plurality of positioning grooves are respectively formed in the surface of the power distribution cabinet body, and the plurality of bolts are respectively arranged between the plurality of positioning blocks and the power distribution cabinet body.
7. The line fault type identification method according to claim 5, wherein the moving assembly comprises a fixed rod, a separation block, two moving sleeves and two connecting brackets, the separation block is connected to the center of the surface of the fixed rod, the two moving sleeves are respectively sleeved on the surface of the fixed rod and are respectively connected with the left side and the right side of the separation block, and the two connecting brackets are respectively connected to the bottoms of the two moving sleeves.
8. The line fault type identification method according to claim 5, wherein the protection assembly comprises two protection plates and two magnetic attraction blocks, the two protection plates are respectively connected to bottoms of the two connection brackets, and the two magnetic attraction blocks are respectively connected to opposite sides of the two protection plates.
9. The line fault type identification method according to claim 5, wherein a mounting assembly is provided between the fixing rod and the power distribution cabinet body, the mounting assembly includes a mounting ring, a mounting seat and two threaded connection bolts, the mounting ring is connected to a surface of the fixing rod, and the mounting seat is connected to a bottom of the mounting ring.
10. The line fault type identification method of claim 9, wherein both of the threaded connection pins are disposed between the mounting base and the power distribution cabinet body.

Description

Line fault type identification method Technical Field The invention relates to the field of fault detection of low-voltage distribution networks, in particular to a line fault type identification method. Background The low-voltage distribution network is the last kilometer of the power system facing the end user and bears the functions of electric energy distribution, metering monitoring and safety protection. The manual closing test transmission can only be judged by experience, has low efficiency and poor accuracy, can not rapidly distinguish overload tripping, short-circuit fault tripping, heavy load input tripping and long-distance short-circuit tripping, is easy to cause long fault checking time and slow in recovering power supply, and seriously influences the power consumption experience and the power supply reliability of users. Therefore, it is necessary to provide a line fault type identification method to solve the above technical problems. Disclosure of Invention The invention provides a line fault type identification method, which solves the problems that the fault type cannot be identified quickly and accurately after the tripping of a low-voltage distribution network, the manual judgment efficiency is low and the accuracy is poor. In order to solve the above technical problems, the present invention provides a line fault type identification method, including: overload tripping, typical short circuit tripping, and heavy load and large load input/long distance short circuit tripping; The tripping of the overload comprises the following steps: S1, collecting and storing current waveform maximum absolute value data of 10 cycles before tripping; S2, calculating the change slope K of adjacent cyclic current according to the formula of K= (I 2−I1)/(t2−t1); S3, judging the conditions that the circuit breaker trips, and the current change slope K of all adjacent waveforms is less than Kset1; s4, identifying a conclusion that overload causes overcurrent and causes overcurrent protection tripping of the circuit breaker is judged; The typical short circuit trip comprises the steps of: S1, collecting and storing current waveform maximum absolute value data of 10 cycles before tripping; S2, calculating the change slope K of adjacent cyclic current according to the formula of K= (I 2−I1)/(t2−t1); s3, judging the conditions that the circuit breaker trips, and the current change slope K of any adjacent waveform is larger than Kset2; s4, identifying a conclusion that the current mutation is caused by the short circuit fault, so that the overcurrent protection of the circuit breaker is tripped; the tripping of the heavy load and heavy load input/long-distance short circuit comprises the following steps: s1, collecting and storing current, voltage waveforms and phasor data of 10 cycles before tripping, and calculating the current change slope K of adjacent cycles; s2, slope preliminary screening, namely judging that Kset1< K < Kset2 is met, and entering an impedance angle precise distinguishing process. S3, calculating phasor; S4, judging the impedance angle. Preferably, kset1 is a large load characteristic slope, and Kset2 is a short circuit characteristic slope. Preferably, the phasor calculation comprises the following scenes of high-load input scenes of fault current phasorsCalculating the impedance angle phi=arg #); Remote short-circuit scene fault current phasorCalculating the impedance angle phi=arg #)。 Preferably, the impedance angle judgment comprises the following steps of judging that the heavy load is put into tripping under heavy load if phi is more than 45 degrees; if phi <45 degrees, the fault deviation resistance is judged to be the tripping of the long-distance short-circuit fault. Preferably, the tripping operation of overload is performed by using low-voltage distribution network electric equipment, the low-voltage distribution network electric equipment comprises a power distribution cabinet main body, a heat dissipation assembly, two moving assemblies and a protection assembly, the heat dissipation assembly is arranged on the back surface of the power distribution cabinet main body, the two moving assemblies are respectively arranged on the upper side and the lower side of the back surface of the power distribution cabinet main body, and the protection assembly is arranged between the two moving assemblies. Preferably, the heat dissipation assembly comprises a heat dissipation net, a plurality of positioning blocks, a plurality of positioning grooves and a plurality of bolts, wherein the positioning blocks are respectively connected to the left side and the right side of the top and the bottom of the heat dissipation net, the positioning grooves are respectively formed in the surface of the power distribution cabinet body, and the bolts are respectively arranged between the positioning blocks and the power distribution cabinet body. Preferably, the moving assembly comprises a fixed rod, a sep