JPH0326771Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to failure section selection in a ring main power distribution network that supplies power by connecting in a ring.

[Conventional technology]

Conventionally, this type of device combines a ground fault direction relay with a direction detection function inside the power protection relay, a zero-phase voltage detector, a zero-phase current transformer, etc. The circuit breaker was activated by determining the side of the circuit.

That is, in FIG. 3, 1 is a high voltage transformer on the power receiving side, 2 is a power receiving protection circuit breaker, 3 is a bus bar on the feeder side, 4a to 4g are feeder side protective circuit breakers,
5a to 5g are load side transformers, 6a to 6g are zero phase current transformers for detecting ground fault current, 7a to 7g are ground fault direction relays, 8 is a zero phase voltage detector, and zero phase current transformers 6a to 6g. and the ground fault direction relays 7a to 7g are connected in a one-to-one manner, respectively, and the zero-phase voltage detector 8 is connected in parallel to all the ground fault direction relays 7a to 7g. In this way, when a ground fault occurs in a system to which various devices are connected, the zero-phase current transformers 6a to 6g detect the ground fault current, and the zero-phase voltage detector 8 detects the voltage phase shift due to the ground fault. Ru.

Based on this ground fault current and voltage phase shift, it is determined whether the ground fault occurs on the power supply side of the zero-phase current transformer 6a to 6g, and if it is on the load side, the circuit breaker 4a
~4g is operated to disconnect the load side circuit. On the power supply side, for example, in the case of the bus 3, the ground fault direction relay 9 operates the upper circuit breaker 2 to quickly break the circuit.

[Problem that the invention attempts to solve]

Since the conventional failure section detection device is configured as described above, it has to process two elements, zero-sequence current and zero-sequence voltage, which has led to the problem that the device is expensive.

This invention was made to solve the above-mentioned problems, and the purpose is to construct an inexpensive device that can detect not only ground faults but also short circuit faults.

[Means for solving problems]

The fault section device according to this invention is an indicator that has a coil that is excited by the secondary current of a current transformer or a zero-phase current transformer and a contact that is operated by the excitation of this coil, and that performs an indicating operation by the operation of this contact. It is composed of

[Effect]

The fault section detection device in this invention operates an indicator using abnormal current detected by a current transformer or zero-phase current transformer using contacts that operate quickly, and displays the operation of contacts that tend to operate unstablely using pulse signals. The display unit's self-holding circuit ensures stable operation of the display unit.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

In the figure, numerals 1 to 6 are the same as those of the conventional device described above, so their explanation will be omitted. In Figures 1 and 2, 10 is a fault indicator, and a current transformer 11 is inside.
Coil 12X connected to X, 11Y, respectively.
Coil 1 connected to 12Y and zero-phase current transformer 6
It has 3. The fault indicator 10 has a coil 12
It has a contact 14, such as a reed switch, which operates by excitation of X, 12Y, 13, and this contact 14
is connected in series with the coil 15 of the display, and further connected in series with a reset switch 22, that is, a reset means, and is supplied with external power supplies P and N. In addition, current transformers 6, 11X, 11Y, coil 1
2X, 12Y, 13, and the contact 14 is called a failure detection means. A self-holding contact 16 driven by a coil 15 is connected in parallel to the contact 14, and when the indicator coil 15 is energized, the contact 16 closes to self-hold the circuit. Further, the operation of the coil 15 of the display causes the other display contacts 17 to operate and send a contact signal to the outside. Note that the coil 15 and the contacts 16 and 17 are referred to as display means. Failure indicator 1 configured in this way
0 is configured into a ring main power distribution network as shown in FIG. That is, two ring switches 18 and 19 are connected in series to the bus bar 3 in each of the switches 21a to 21g forming the power distribution network, and branch switches 20a to 20g are T-branched from between these two ring switches 18 and 19. each connected. Load-side transformers 5a-5g are connected to branch switches 20a-20g, respectively. Current transformers 11Xa to 11Xg, 11Ya to 11Yg and zero-phase current transformers 6a to 6g are provided on the side of the ring switches 19a to 19g, and their outputs are connected to a failure indicator 10. In a ring main power distribution network configured in this way, each load-side transformer 5 is normally connected when either ring switch 18 or 19 is open, that is, the ring is disconnected.
Power is supplied to a and 5g. For example, in FIG. 2, ring switches 19d and 18e are open. With such a configuration, the ring network, that is, the bus 3
When an accident such as a short circuit or ground fault occurs on the upper or load side transformer 5a to 5g side, the fault indicator 10 from the power receiving protection circuit breaker 2 to the fault point operates with an overcurrent of more than a predetermined value. The location of the accident is determined based on the presence or absence and number of. Based on this result, the faulty section is isolated. The fault indicator 10 is reset by, for example, opening the reset switch 22 by remote control, but if the reset switch 22 is set to an automatic reset method using a timer or the like, the fault indicator 10 is reset within a certain period of time after the occurrence of an accident is indicated. will be automatically reset,
You can prepare for the next accident.

Furthermore, it is desirable that the contact 14 be capable of high-speed operation (operation within 6 mS) in order to cope with repeated alternating inputs using alternating current.

In the above embodiment, a two-phase current transformer and a zero-phase current transformer are combined, but a three-phase current transformer can also be used. It can be attached to either side of 19.

[Effect of idea]

As mentioned above, according to this invention, overcurrent indicators are arranged distributed on the busbar, and when an accident occurs, the fault section is detected by operating the indicators up to the fault point, which is complicated. The advantage is that there is no need to provide a phase detection device, and the system can be configured at low cost.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the configuration of a ring main power distribution network according to an embodiment of this invention, Figure 2 is a circuit diagram showing the configuration of a fault indicator according to an embodiment of this invention, and Figure 3 is a diagram showing a conventional power distribution network. The circuit configuration is shown below. In the figure, 3 is the busbar of the ring main distribution network,
6 is a zero-phase current transformer, 10 is a fault indicator, 11 is a current transformer, 18 and 19 are ring switches, and 20 is a branch switch. In the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Scope of utility model registration request] The power feeding unit and the power distribution network include a power feeding bus, a power feeding part that supplies power to the power feeding bus, and a plurality of branch parts arranged along the power feeding bus and branching from the power feeding bus in a T-shape. In a fault section detection device that includes at least one fault indicator arranged at a branch and between the branch parts, and detects a fault section based on the presence or absence of operation of each fault indicator, the fault indicator detects a line current. and failure detection means for operating a reed switch and outputting a failure signal when at least one of the zero-sequence currents exceeds a predetermined value; 1. A fault section detection device comprising: a display means for holding the display; and a reset means for stopping the display on the display means.