CN103022992A - Feeder ground positioning method based on dispersion zero sequence voltage detection - Google Patents

Abstract

The invention discloses a feeder grounding positioning method based on decentralized zero-sequence voltage detection. The grounding fault processing of the line is realized by using the feeder automation system. The method includes: fault monitoring; fault tripping: outgoing line circuit breaker protection tripping, segment The switch opens, and the FTU uploads the signal; Fault location: through the detection of zero-sequence voltage, the fault area is judged; Fault isolation, the switch at both ends of the fault point is locked; Power supply restoration: After the ground fault point is eliminated, then the blocked section switch is controlled to close , to restore power to the faulty area. When the invention handles the grounding of the line, it can quickly locate the grounding area and automatically isolate it. It does not require personnel to go to the site to check the entire line, effectively reducing manpower and resource consumption, and is convenient for troubleshooting personnel to eliminate the fault point in time, which not only effectively guarantees line maintenance. The safety of personnel and line equipment, while reducing the power outage time of the line and the loss caused by power outage users, greatly improves the reliability of power supply.

Description

Feeder grounding location method based on decentralized zero-sequence voltage detection

technical field

The invention relates to the field of distribution network feeder automation, in particular to a feeder grounding positioning method based on decentralized zero-sequence voltage detection.

Background technique

According to statistics, single-phase grounding faults on 10kV lines account for more than 30% of line faults. Single-phase grounding of lines is more harmful, specifically reflected in the following aspects:

(1) Hazardous substation equipment. After a single-phase ground fault occurs on a 10kV distribution line, the iron core of the voltage transformer is saturated, and the excitation current increases. If it is operated for a long time, the voltage transformer will be burned. It may also generate a resonant overvoltage several times higher than the normal voltage, endangering the insulation of the substation equipment, and in severe cases, the insulation of the substation equipment will break through, causing even greater accidents.

(2) Hazardous power distribution equipment. After a single-phase ground fault occurs, intermittent arcing may occur, resulting in resonant overvoltage. The overvoltage will further cause insulation breakdown of the insulator on the line, resulting in a serious short circuit accident. At the same time, the distribution transformer may be burned, causing the lightning arrester and fuse insulation on the line to break down and burn out. In severe cases, an electrical fire may occur.

(3) Harm the distribution network. Serious single-phase ground faults may destroy the stability of the regional power grid system, cause greater accidents, and affect the reliability of power supply.

(4) Endangering personal safety. For single-phase ground faults such as the grounding of conductors, human-induced electric shock casualties may occur for pedestrians and line inspectors.

(5) Affect line loss. When a single-phase ground fault occurs, because the grounding of the distribution line directly or indirectly discharges the ground, it will cause a large power loss.

At present, when the 10KV feeder line is grounded, the traditional treatment method is to stop the grounding line and manually check the grounding point of the line, which often takes a long time and a lot of manpower and material resources, resulting in long-term power outages and waste of resources.

Contents of the invention

The invention provides a feeder grounding positioning method based on decentralized zero-sequence voltage detection, which effectively solves the problems of time-consuming and labor-intensive processing of line grounding and affecting power supply.

In order to solve the above problems, the present invention adopts the following technical solutions: a feeder grounding positioning method based on decentralized zero-sequence voltage detection, and realizes the processing of line grounding faults by using the feeder automation system, which is characterized in that,

The feeder automation system includes:

A substation outlet circuit breaker is set at the output end of each substation, and each substation controls a power distribution line;

Different power distribution lines are connected through a tie switch, and the tie switch is in an open state under normal conditions;

Several subsection switches are arranged on the power distribution main line, and an FTU with zero-sequence voltage detection function is installed at each subsection switch, and the subsection switch forms a communication connection with the distribution automation master station ;

The described method includes the following processes:

Fault monitoring, the process of fault tripping is: the outlet circuit breaker of the substation monitors in real time whether the line grounding is faulty;

Fault tripping, the process of fault tripping is: when a line grounding fault occurs at a certain point on the line, the circuit breaker of the substation outgoing line detects the line grounding fault, the protection action trips, and all the section switches on the line are opened due to voltage loss, At the same time, the FTU on the faulty line detects the zero-sequence voltage and uploads it to the distribution automation master station through the sub-section switch;

Fault location, the process of fault location is: after the set time, the substation outgoing line circuit breaker will automatically close, and the section switches on the faulty line will be in the order of distance from the substation from near to far, with the set time as the time limit. Closing, when the section switch is closed, the FTU on the section switch is energized to work, and detects whether there is zero-sequence voltage in the line. When a certain FTU detects zero-sequence voltage, the section switch where the FTU is located automatically Block and send information to the main station system to locate the fault zone as the back end of the block switch;

Fault isolation, the process of fault isolation is: after the section switch at the front end of the fault area is locked, and after the set time, the section switch or contact switch at the back end of the fault area maintains a locked state due to voltage loss, realizing the fault area isolation;

Restoring power supply, the process of restoring power supply is as follows: after the line maintenance personnel search and eliminate the grounding fault point in the fault power outage area, then control the closed section switch to close and restore the power supply in the fault area.

Further, the setting time described in the above method is 7 seconds.

Further, in the process of restoring power supply described in the above method, when the rear end of the fault area is a section switch, the tie switch will enter the countdown time after the first trip, and the tie switch will automatically close after the countdown time ends, realizing the substation at the other end. Power supply to the rear part of the fault zone.

Further, the countdown time described in the above method is 45 seconds.

Further, in the process of restoring the power supply described in the above method, the closing of the blocking section switch can be realized through one of two ways of remote control and on-site manual operation.

The beneficial effects of the present invention are: when the present invention handles the grounding of the line, it can quickly locate the grounding area and automatically isolate it, without the need for personnel to go to the site to check the entire line, effectively reducing manpower and resource consumption, and facilitating the timely troubleshooting of fault points by troubleshooting personnel , not only effectively guarantee the safety of line maintenance personnel and line equipment, but also reduce the power outage time of the line and the losses caused by power outage users, and greatly improve the reliability of power supply.

Description of drawings

Fig. 1 is a schematic flow sheet of the present invention;

Fig. 2 is a schematic circuit diagram of an embodiment of the present invention.

Detailed ways

As shown in Figure 1, the invention provides a feeder ground fault location method based on distributed zero-sequence voltage detection, which realizes the processing of line ground faults by utilizing the feeder automation system.

The feeder automation system includes:

A substation outlet circuit breaker is set at the output end of each substation, and each substation controls a power distribution line;

Different power distribution lines are connected through a tie switch, and the tie switch is in an open state under normal conditions;

Several subsection switches are arranged on the power distribution main line, and an FTU with zero-sequence voltage detection function is installed at each subsection switch, and the subsection switch forms a communication connection with the distribution automation master station ;

The described method includes the following processes:

Fault monitoring, the process of fault tripping is: the outlet circuit breaker of the substation monitors in real time whether the line grounding is faulty;

Fault tripping, the process of fault tripping is: when a line grounding fault occurs at a certain point on the line, the circuit breaker of the substation outgoing line detects the line grounding fault, the protection action trips, and all the section switches on the line are opened due to voltage loss, At the same time, the FTU on the faulty line detects the zero-sequence voltage and uploads it to the distribution automation master station through the sub-section switch;

Fault location, the process of fault location is: after 7 seconds, the substation outlet circuit breaker will automatically close, and the subsection switches on the faulty line will be closed sequentially according to the order of distance from the substation from near to far, taking 7 seconds as the time limit , while the section switch is closed, the FTU on the section switch is powered on to detect whether there is a zero-sequence voltage in the line. When a certain FTU detects the zero-sequence voltage, the section switch where the FTU is located is automatically blocked. And send a message to the main station system to locate the fault zone as the back end of the blocking section switch;

Fault isolation, the process of fault isolation is: after the segment switch at the front end of the fault area is locked, after 7 seconds, the segment switch or contact switch at the rear end of the fault area maintains a locked state due to pressure loss, so as to realize the isolation of the fault area. isolation;

Restoring the power supply, the process of restoring the power supply is: after the line maintenance personnel go to the fault power outage section to find and eliminate the ground fault point, and then realize the closing of the blocking section switch by means of remote control and on-site manual operation, Restore power to the faulty area.

Further, in the process of restoring power supply, when the back end of the fault area is a section switch, the tie switch will be automatically closed 45 seconds after the first trip, so as to realize the power supply of the substation at the other end to the back end of the fault area.

Fig. 2 is a schematic circuit diagram of an embodiment of the present invention. As shown in Figure 2, the wiring diagram of a typical 10kV tie line, K is the substation outlet circuit breaker, K1, K2, K3 is the section switch, T is the tie switch, FTU1, FTU2, FTU3 are equipped with zero-sequence voltage detection function FTU, assuming that point A occurs at the grounding point, the processing process is as follows:

1) When grounding occurs, K detects the line grounding fault, the protection action trips, and K1, K2, and K3 all open due to voltage loss; at the same time, FTU1, FTU2, and FTU3 on the line detect abnormal zero-sequence voltage and upload it to the main stand;

2) After 7 seconds, K automatically closes, and after 14 seconds, K1 closes, and FTU1 detects the zero-sequence voltage after it is powered on. Since there is no abnormal zero-sequence voltage signal, the closing is normal;

3) After 21 seconds, K2 is closed, and the zero-sequence voltage is detected after FTU2 is powered on. The zero-sequence voltage signal is abnormal, the closing is abnormal, K2 is blocked, and the fault location is located at the rear end of K2;

4) After 28 seconds, K3 loses voltage, no current is detected, and it is still in the locked state, realizing the isolation of the fault area;

5) After 45 seconds, T is closed, and the transformer at the other end supplies power to the line between K3 and T;

6) The dispatcher informs the line maintenance personnel to find the ground fault point in the fault power outage section. Since the fault has been isolated and the power is cut off, the maintenance personnel will not be in danger of working. After the line maintenance personnel find the fault point and repair and eliminate it, notify Dispatchers remotely close the FTU2 switch or maintenance personnel close the switch locally to restore the power supply in the blackout section.

The above is only a preferred embodiment of the present invention. For those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications are also considered as the present invention. protection scope of the invention.

Claims (5)

1. based on the feeder line grounding locating method that disperses zero sequence voltage detection, realize the processing of line-to-ground fault by utilizing feed line automatization system, it is characterized in that,

Described feed line automatization system comprises:

Output in each transformer station arranges transformer station's wire-outgoing breaker, and distribution line of described each Substation control;

Connect by interconnection switch between the different distribution lines, described interconnection switch is in open mode under normal conditions;

Be provided with some block switches at the distribution basic routing line, a FTU who possesses the zero sequence voltage detection function is all installed at described each block switch place, and described block switch and the formation communication connection of power distribution automation main website;

Described method comprises following process:

Malfunction monitoring, the process of described fault trip is: whether transformer station's wire-outgoing breaker Real-Time Monitoring line-to-ground breaks down;

Fault trip, the process of described fault trip is: when line-to-ground fault occurs certain point on the circuit, transformer station's wire-outgoing breaker detects line-to-ground fault, protection action tripping operation, all block switches are all because of the decompression separating brake on the circuit, meanwhile, the FTU on the faulty line detects residual voltage, and uploads to the power distribution automation main website by block switch;

Fault location, the process of described fault location is: through behind the setting-up time, transformer station's wire-outgoing breaker automatic closing, block switch on the faulty line can be by distance transformer station order from the close-by examples to those far off, close a floodgate successively take setting-up time as the time limit, when block switch closes a floodgate, FTU on the block switch gets electric work, whether there is residual voltage in the detection line, when some FTU detect residual voltage, the block switch automatic blocking at this FTU place, and send information to main station system, orient the rear end that fault section is the locking block switch;

Fault Isolation, the process of described Fault Isolation is: after the block switch locking of faulty section front end, pass through setting-up time again after, the block switch of faulty section rear end or interconnection switch are kept blocking because of decompression, realize the isolation to faulty section;

Restore electricity, the described process of restoring electricity is: line attendant is to the fault outage range lookup and after getting rid of earth fault, and the block switch of controlling again locking closes a floodgate, and recovers the power supply of faulty section.

2. the feeder line grounding locating method based on disperseing zero sequence voltage detection according to claim 1 is characterized in that described setting-up time is 7 seconds.

3. the feeder line grounding locating method based on disperseing zero sequence voltage detection according to claim 1, it is characterized in that, in the described process that restores electricity, when the faulty section rear end is block switch, interconnection switch can enter the countdown time after the tripping operation for the first time, interconnection switch auto-closing after the countdown time finishes realizes that other end transformer station is to the power supply of faulty section rear end part.

4. the feeder line grounding locating method based on disperseing zero sequence voltage detection according to claim 3 is characterized in that the described countdown time is 45 seconds.

5. the feeder line grounding locating method based on disperseing zero sequence voltage detection according to claim 1, it is characterized in that, in the described process that restores electricity, can be by a kind of combined floodgate of realizing the locking block switch in Remote and the on-site manual operation dual mode.

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