JPS6318922A - Distribution lines remote monitor and control system - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a distribution line remote monitoring and control system, and more particularly to a distribution line remote monitoring and control system suitable for detecting ground faults on distribution lines and searching for ground fault points. .

[Conventional technology]

Conventionally, when an accident occurs on a power distribution line, in order to quickly distinguish between a healthy section and an accident section, a "divider switch for automatic failure section detection" has been used, and the switch is automatically switched on and off at preset time intervals. When charging the faulty section, a protective relay installed at the distribution line exit of the substation immediately opens the distribution line exit breaker (hereinafter referred to as CB) to determine in which section the fault is occurring. , a method has been put into practical use to quickly restore power supply to otherwise healthy sections, but this method requires that a large number of automatic switching switches (hereinafter referred to as DMs) be installed to shorten the fault section. (divide the power outage section into shorter sections). However, in the event of an accident, it takes a long time to restore the power to the end of the distribution line.
DM is only provided. Therefore, in order to divide the accident section (power outage section) into shorter sections, many manual section switches (hereinafter referred to as AS) are installed between DMs.

The system is operated manually to open and close in order to detect the accident section and minimize the area of power outage.

A specific example of the conventional method will be described below.

FIG. 4 is a simplified diagram for explaining the operation of DM in the case of two distribution lines.
Distribution lines 1 and 2 provided with distribution line outlet switches CB; and CB2 are connected to uS.

D'M17 is a DM installed at the butting point of the rewriting power line, and is in an open state under normal conditions (both sides are energized), but when there is no voltage on either side for a certain period of time or more, it is automatically turned on. do. That is, the voltage on the distribution line 1 side is
In I, the voltage on the distribution line 2 side is derived from each voltage transformer PTbz, and in the control bag [L, the presence or absence of that voltage is monitored. As mentioned above, if the power outage continues, issue a command to turn on DM17,
It functions to transmit power backwards to the distribution line on the power outage side.

DM 15, DM tz and DM 18 are DMs connected in series to the distribution line 1, and DM s 1
When the CBs are turned on and the section 11 is pressurized, the controller F1 automatically turns them on after a certain period of time, and puts the section 12 in a pressurized state. DM engineering z is section 12 or section 13
After a certain period of time has elapsed after either of the f! The difference between Fl and C1 is that Fl responds only to pressure from one predetermined side (section 11 in this example), whereas C1 responds to pressure from either side. This is the point.

Also, for both Fl and C1, a certain period of time (Y time) after DM is input.
If the line voltage disappears within that time, it is determined that an accident has occurred in the section energized by the DM and the CB L has tripped, the DM is opened, and subsequent closing operations are locked. . However, in the event of a power outage after 7 hours,
The DM is simply pulled out, and the closing operation is not locked.

Furthermore, for C1, the voltage application state on one side is within a certain time period (within X time period and before automatic input)! ! When lightning voltage is reached, subsequent closing operations are locked.

The above is an explanation of Fl and 01.

F2 operates in exactly the same manner as Fl, and C2, C3, and C4 operate in exactly the same manner as C1.

As explained above, Fl, F2. Each of the control devices C1 to C4°L and the section starters DMII to DM1? .

Voltage transformer PTFl, PTFl, PTSs~
PT4z.

P T Ll 1 P T L= + In a distribution system consisting of distribution lines a1 and 2 that have distribution line pull-out switches CBI and CB2, there was an accident on the distribution line 1 side, CB 1 tripped, and then the accident occurred. FIG. 5 shows a time chart when the route is normally restarted when the cause disappears.

Due to an accident occurring on distribution line 1, CB 1 trips. At this time, sections 11 to 14 are in a no-voltage state, and the DM
II to DM13 are in an open state. At this time, DM1
The control device that controls section 7 is in a energized state only on the section 18 side, and the start timer z1 operates for automatic power-on.

Approximately one minute after the CBz trip due to the accident, CB 1 performs the re-route operation. Then 1 section 11~
14 is due to the automatic charging after one-sided charging of D M s 1 to D M 1 g after the charging confirmation time X time period, and the voltage is charged in the section 14 in sequence.

The control device enters a state in which a common current is applied to both ends, resets Zl, and maintains the open state of the DM 17 (Z'l is normally set for several minutes to several tens of minutes).

Now, in the operational state shown in Figure 4, an accident occurs in section 12 and the time chart in case the cause of the accident continues is shown in Figure 6.
As shown in the figure. First, due to the accident that occurred in section 12, outlet CB 1 of distribution line 1 was tripped by the protective relay, and sections 11 to 14 were in a no-voltage state, and DMzt to DM
13 is in an open state.

CB t is restarted by relay after tripping.

After a certain period of time (usually 1 minute), it will be re-injected. By turning on CBl, section 11 becomes energized state, timer Xll for turning on Fl starts, and after a certain period of time (usually 0 times value of 6 to 10 seconds), it times up and turns on D M sl again.
Section 12 enters the charging state. At this time, Fl starts the healthy input confirmation timer Yll, and C1 activates the input timer X1.
Start 2. Section 12 has accident factors, so
CBi trips again and one section 11.12 becomes a no-voltage state, and Yll and X12 are reset without timer up. Therefore, Fl is D M s t and C1 is D
Locks the subsequent automatic input function of M12.

Below, the operation of the power distribution system is as shown in Figure 6.
After tripping again, the circuit is closed again after a preset time limit (usually 1 minute later) and 1 section 11 is energized, but since Fl is locked from automatic turn-on, DM+z for subsequent sections
Power will not be supplied via.

On the other hand, L existing at the butt point of distribution line 1.2 is section 14
has started its timing operation from the power outage state, and when the timer Z1 times up, DM17
is automatically turned on, and the section 14 is placed in the energized state. the result,
After C2 has elapsed for a certain period of time (X13), D M l a is turned on and 1 section 13 is brought into the aW& state.

C2 is locked for a certain period of time (X
12) After that, the DM 12 remains open, and the accident zone 12 is automatically separated by the operation of CB t and each DM.

After disconnecting the fault section 12 as described above, the AS installed for minimizing the range of power outage supply disturbance in section 12 and searching for the fault point was artificially opened at the site to minimize the power outage range. There is.

For example, as shown in Fig. 7, 10 subdivided sections 121 to 130 are provided by 9 ASs, and the always closed A
After manually opening one of S1 to ASs (for example, AS4), DM1s (DMI
! ), it is confirmed whether there is an accident between DMII (DMtz) and AS4, and the healthy sections are gradually restored. In other words, if there is an accident when the DM is turned on, leave AS4 off and turn on the DM5.
is input to restore the first section 125 to section 130. After that, similar opening/closing operations are performed between DMlt and AS4 to expand the restoration range and limit the power outage section.

In addition, as a method for separating this type of accident section,
There is one shown in No. 52839 "Accident detection device for sectional switchgear".

[Problem that the invention seeks to solve]

As is clear from the above explanation, in the conventional control method,
Automatic exception of the accident zone (section divided by DM and DM) is made possible by re-closing the distribution line outlet CB, and the accident zone can be minimized by manual operation of the manual switch AS at the site. I was dependent on it.

As a result, there was a problem in that restoration of power outage in healthy sections was delayed.

An object of the present invention is to provide a distribution line remote monitoring control system that can quickly restore a power outage in a healthy section.

[Means for solving problems]

The present invention focuses on the fact that most accidents in power distribution systems are line-to-ground faults (over 90% of the accidents that occur). A detection circuit is provided to detect one or both of the currents, and when the detection circuit detects a zero-sequence voltage or zero-sequence current that is equal to or higher than a set value within a predetermined time after the sectional switch is turned on, the sectional switch This system determines that there is a ground fault in the electrified section due to the power input, and opens the corresponding sectional switch.

[Effect]

If a zero-sequence voltage or zero-sequence current equal to or higher than the set value is detected within a predetermined time after the sectional switch is turned on, it will be determined that a ground fault has occurred, and the substation's protective relay will trip the distribution line outlet CB. Before operation, the section switch is opened.

Therefore, a healthy section can be restored with just one power outage.

〔Example〕

FIG. 1 is a block diagram showing an embodiment of the additional function section of a DM control device to which the present invention is applied. When the DM enters a one-side energized state and after a certain time period (X time period) has elapsed, this DM control device Perform input operation for DM. The AND circuit 34 is established for T1 seconds from when the contact 31 is turned on by the input of the DM until the time limit timer 32 times up. When the 0vG (ground fault voltage) detection circuit 35, which detects whether the zero-sequence voltage of the grid exceeds a preset detection level, operates within the aforementioned 71 seconds, the timer 33 starts, and It then operates to remove the DM.

Here, T 1 + T z seconds is arranged to be shorter than the operating time of the protective relay that trips the distribution line outlet CB. In addition, the above-mentioned DM tripping circuit operates a UV (short-circuit fault) detection circuit 36 to detect a short-circuit fault or a two-wire ground fault, and when the line voltage falls below a preset detection level, a logic The product circuit 34 is not established, and the tripping operation of the DM is locked.

Next, regarding the operation of the AS, the AS control system [50
This will be explained using a block diagram. In Figure 2, the voltage across AS is derived from PT^ or PT^2,
The “present” or “absent” condition of the voltage in each section is determined by the output of the ○R circuit 52 which receives the output of each UV (short-circuit accident) detection circuit 51, and only when the voltage is “present” in either one, a one-shot The circuit 53 operates and the memory circuit 54 is set.

When the memory circuit 54 is set, a timer 55 is activated, and the memory circuit 54 is reset after 11 seconds. If the distribution ftea has a power outage within this 71 seconds, the UV detection circuit 51 operates together, the OR circuit fails, the AND circuit 56 is established, and the AS is tripped. Here, the reason why the time limit timer 57 is set as a confirmation time of 12 seconds is as a countermeasure against instantaneous power failure.

In the power distribution system shown in Fig. 4 in which the functions of the above configuration are added to the control device of each DM, the power distribution system is currently in a normal state (section 11 to section 1).
It is assumed that a single-line ground fault occurs in one section 12 when all lines 8 are in the energized state). The time chart at this time is the third
As shown in the figure.

First, due to the single line ground fault accident in section 12, C
B5 trips, sections 11 to 14 suddenly experience a power outage, and D M ls - D M t a become open. At this time, the DMlt is in the energized state only in section 18, and the startup timer z1 for automatic power-on starts counting. Thereafter, after tripping, CB1 is reclosed after a preset time period, and section 11 is energized. Fl is a fixed time limit (Xl
l) After that, the DMII is turned on and the section 12 is placed in a energized state, but the fault point in the section 12 is charged, and a ground fault voltage is generated. As shown in Figure 1, after turning on the DM, if the zero-sequence voltage of the system exceeds a preset value within 71 seconds, Fl automatically disconnects the DM and disconnects the section. 12 is in a power outage state. By performing this DMxs tripping operation earlier than the operating time of the protective relay installed in the substation that issues the trip command for the distribution line outlet CB L, the section 11 maintains the energized state. After that, the control device located at the butting point of the distribution lines 1 and 2 continues to measure time, and as Zl times up, DM17
is automatically input, and section 14 is set to 1ffl state. As a result, after a certain period of time (X13) has elapsed, C2 inputs the DM s and completes section 13! Power on. Since the automatic injection is locked for C2, DM12 is not available even after a certain period of time (X12) has elapsed.
remains open and the accident section 12 is automatically separated.

In this way, on distribution line 1, one power outage (CBL)
(no need to close the circuit again), it becomes possible to identify and separate the accident section. Furthermore, in the event of a short-circuit accident involving two or more wires at the ground end, the immediate release function of the DM will not respond, and the fault section will be disconnected by re-closing the circuit by tripping the distribution line exit CB at the substation as before.

In addition, in this embodiment, single gland ground fault detection was described using only the zero-sequence voltage, but it is also possible to take in the zero-sequence current (Z
It is possible to have directionality in ground fault detection by combining it with zero-sequence voltage, or simply by using ground fault current alone, it is possible to detect - line termination faults. It is also easy to do.

Now, when the accident section partitioned by DM is automatically separated, the AS in the accident section will, within a certain period of time after changing from the power outage state to the power supply state, according to the block configuration shown in Figure 2. When a power outage occurs, it becomes open. In other words, in this embodiment, when DMst is turned on and DMst is tripped due to a - line ground fault, the A S shown in FIG.
1 to A S s are all open.

Therefore, by controlling the AS using a wired system or a power line transport system according to the following procedure, it is possible to limit the accident section (restoration of a healthy section).

That is, in FIG. 7, D M L and D M
1z is locked and A S 1 to A in this section
All S a are in the "open" state. First, DM 1□
Or DM 12 releases the lock by remote control,
It is possible to input or replace the crop. If an accident remains in section 121 or section 129 at this time, CBi or CB 2 will trip, making it possible to determine whether the accident is in a subdivided section by AS. When there are no accidents, the next section,
For example, ASl, AS2. A health check is performed by remote control of either Ash or AS9.

In this way, by sequentially controlling from a distance, it becomes possible to limit accident sections and restore healthy sections.

In this way, it is now possible to perform AS control from a distance, which was previously done manually at the site, which will have a huge effect on searching for accident areas and quickly restoring power outages. .

〔Effect of the invention〕

As is clear from the above description, the present invention is advantageous.

- There is no need to repeatedly close the distribution line outlet CB when an accident such as a line ground fault occurs, and a healthy section can be restored with just one power outage, which has a great effect.

Furthermore, when the AS is remotely controlled as shown in the embodiment, the power outage section can be kept to a minimum by searching for the accident section.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of an additional function section of a DM control device to which the present invention is applied, FIG. 2 is a block diagram showing an embodiment of an AS control device, and FIG. Figure 2 is a time chart for explaining the operation of a power distribution system with added functions, Figure 4 is a system diagram showing an example of a power distribution system to which the present invention is applied, and Figures 5 and 6 are diagrams based on a conventional control system. A time chart for explaining the operation of the sectional switch, and FIG. 7 is a wiring diagram showing an enlarged view of the accident section. CBx, CBz... Distribution line outlet switch, D M t
t~DM 17... Sectional switch, Fl, F2. C
1 to C4...control device, AS1-ASe・
・・Manual compartment switch, 32° 33・・Timer, 3
5... Ground fault voltage detection circuit. 36... Short circuit accident detection circuit, 50... AS control device, 51... Short circuit accident detection circuit, 54... Memory circuit,
55°57... Timed timer.

Claims (1)

[Scope of Claims] 1. A detection circuit for detecting one or both of zero-sequence voltage and zero-sequence current is provided in sectional switches distributed in the distribution line, and a detection circuit for detecting either or both of zero-sequence voltage and zero-sequence current is provided, and a predetermined period of time after the sectional switch is turned on is provided. If the detection circuit detects a zero-sequence voltage or zero-sequence current that is equal to or higher than a set value within a period of time, it is determined that there is a ground fault in the charged section due to the closing of the sectional switch, and the sectional switch is opened. A remote monitoring and control system for power distribution lines. 2. Within the section divided by the section switch, always maintain a closed state, and within a preset time period when voltage is applied,
2. The remote distribution line monitoring and control system according to claim 1, further comprising a second section switch that is opened only when a power outage occurs. 3. When the second section switch, which is normally closed, is in the open state, if there is a power outage within a preset time period after voltage is applied from one side, the subsequent closing operation will be interrupted. A distribution line remote monitoring and control system according to claim 2, characterized in that: 4. Claims characterized in that when the normally closed second section switch is in the open state, electricity is applied from one side, and the switch is automatically turned on when the state exceeds a preset time limit. The distribution line remote monitoring control method described in item 2. 5. If the normally closed second section switch changes from the open state to the closed state and continues to be energized on both sides for a preset time period or longer, the power outage state is maintained thereafter. A distribution line remote monitoring and control system according to claim 2. 6. Claim 2, characterized in that the second section switch, which is always in a closed state, is remotely monitored and controlled.
Distribution line remote monitoring and control method described in Section 2. 7. A detection circuit for detecting one or both of zero-sequence voltage and zero-sequence current is provided in the sectional switches distributed in the distribution line, and the detection circuit is activated within a predetermined time after the sectional switch is turned on. When a zero-sequence voltage or zero-sequence current exceeding a set value is detected, a detection circuit determines that there is a ground fault in the voltage section due to the closing of the sectional switch, opens the sectional switch, and further detects the line voltage. When the line voltage falls below a predetermined detection level, it is determined that a two-wire ground fault, three-wire ground fault, short circuit accident, etc. has occurred, and the removal operation of the sectional switch is locked. Distance monitoring and control system for power distribution lines.