JPH01252120A - Shortcircuit fault point judging device for spot network system - Google Patents

Abstract

PURPOSE:To judge shortcircuit fault quickly and reliably, by judging occurrence of shortcircuit fault if an air circuit breaker is tripped under a condition where a wiring circuit breaker is not tripped and a protector fuse is not blown off. CONSTITUTION:A bus link section air circuit breaker 23 incorporating a bus link section air circuit breaker current transformer 21 and a bus link section air circuit breaker static instantaneous relay 22 is arranged at a bus link section. Wiring circuit breakers 241-244 to be tripped only through instantaneous elements are arranged at the side of distribution paths 191-194. Shortcircuit fault point is judged including trip of the circuit breakers 23, 241-244 and blow-off of protector fuses 14a-14c for respective lines.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an improvement of a short-circuit fault point determination device for a spot network system used in a low-voltage power distribution system.

(Conventional technology) This type of low-voltage power distribution spot network system is
A circuit device, a network transformer, a protector fuse, a protector circuit breaker, etc. are connected in series to each of the three or four distribution lines, and the secondary side of each of these protector fuses is connected to the network busbar. .

A load is connected to this network bus bar side via a required number of molded circuit breakers.

(Problem to be Solved by the Invention) Therefore, in the above-described spot network system, depending on whether or not the molded circuit breaker trips,
It is possible to identify the point of a short-circuit accident in a load circuit, etc., but for example, a short-circuit accident on the next side of a disconnector, a short-circuit accident on the secondary side of a network transformer, or a short-circuit accident between a protector fuse and a protector circuit breaker. Furthermore, there is a problem in that it is difficult to accurately determine short-circuit accident points in various parts of the system, including various parts of each line, mother interconnection section, load circuit, etc. In addition, even when determining the point of a short circuit, it takes a long time and there is a problem that the protector fuse may deteriorate or melt, so that the device for determining the point of a short circuit is still insufficient.

The present invention has been developed in view of the above-mentioned circumstances, and is capable of reliably identifying the point of a short circuit, which was impossible to identify with conventional devices, and also detecting the protector fuse when a short circuit current flows through the motherboard. An object of the present invention is to provide a short-circuit fault point determination device for a spot network system that enables a trip operation before deterioration of the spot network system.

Another object of the present invention is to provide a spot network system short-circuit point determination device that can quickly and reliably determine short-circuit points in each part of the system from a comprehensive perspective and realize highly reliable maintenance. It's about doing.

[Structure of the Invention (Means for Solving the Problems) In order to achieve the above object, the short-circuit failure point determination device for a spot network system according to the present invention separately installs primary disconnectors for N (N is an integer) lines.

In a split bus spot network in which a network transformer, protector fuse, protector circuit breaker, etc. A molded case circuit breaker installed in the distribution line and the non-trip of this molded case circuit breaker.

A short circuit fault point determining means for determining that a short circuit fault has occurred between the secondary side of the network transformer and the protector fuse when the protector fuse is in a non-fused state and the air circuit breaker trips. It is.

Further, the short-circuit fault point determination device for a spot network system according to the present invention provides non-tripping of the molded circuit breaker;
A short-circuit fault point determining means is provided for determining that a short-circuit fault has occurred at any point between the protector fuse and the motherboard when at least two phase protector fuses are in a blown state and the air circuit breaker is tripped. It is something that

Furthermore, the short-circuit fault point determination device for a spot network system according to the present invention logically separates and extracts signals such as the operating status of the air breaker and molded circuit breaker, and whether or not the protector fuses of each phase are blown. Accordingly, the present invention is equipped with short-circuit fault point determination means for determining short-circuit faults in various parts of the system, such as the line, the motherboard, and the load circuit.

(Function) Therefore, the present invention has the above-mentioned means.
Logical combinations of the operating status of the air circuit breaker with a built-in static instantaneous relay connected to the motherboard, the operating status of the molded case circuit breaker installed in the load-side power distribution path, and whether or not the protector fuses of each phase are blown. For example, the point of short circuit between the network transformer secondary side and the protector fuse can be determined from the non-trip of the molded circuit breaker, the non-clear of the protector fuse, and the trip of the air circuit breaker. It is possible to determine a short-circuit accident point at any point between the protector fuse and the motherboard from the non-trip of the molded circuit breaker i, the blown state of at least two phase protector fuses, and the trip of the air circuit breaker, and further By logically dividing signals such as the operating status of the air breaker and molded case circuit breaker, and whether or not the protector fuses of each phase are blown, it is possible to determine the point of a short circuit in each part of the system.

(Example) Hereinafter, FIGS. 1 to 5 will explain an example of the apparatus of the present invention.
This will be explained with reference to the figures. Figure 1 is a system diagram of a 3-line bus split type spot network system, Figures 2 to 4
．． The figure is a configuration diagram for logically determining each short circuit fault point,
FIG. 5 is a flowchart for processing short-circuit fault points using software.

First, the 3-line bus split type low-voltage spot network system consists of - Inside the shell, as shown in Figure 1, each line 11a, 1
Primary disconnectors 12a, 12b, 12 are installed individually in 1b and 11c.
cs network transformer 13a, 13b, 13c, professional 7ktahyuse 14a, 14b, 14c, net'7-
The current transformers 15a, 15b, 15c, protector circuit breakers 16a, 16b, 16c, etc. are connected in series, and the secondary side of each protector circuit breaker 16a, 16b, 16c is connected to the network bus 17.

18a, 18b, and 18c are each line 118.11b.

When the reverse power of 11c is detected, the protector circuit breaker 16a
, 16b, 16c. Also, the network mother I! 17 depending on the number of loads required? ! Number of distribution lines 191°192.193.・
A load (not shown) is connected via...

Therefore, in the power distribution system as described above, the bus section has a built-in current transformer 21 with a built-in bus air circuit breaker and a stationary instantaneous relay 22 with a built-in bus circuit breaker. Circuit breaker 2
3, and on the other hand, molded circuit breakers 241, 242, 243 that trip only with instantaneous elements are installed in the distribution line on the load side.
,... are provided. These circuit breakers 241, 2
The set number of 42, . . . is determined depending on the required number of loads, etc. In addition, in the figure, A is the short-circuit point of the special high-speed line 11a, B is the short-circuit point between the network transformer 13a and the protector fuse 14a, and C is the point between the protector fuse 148, the molded circuit breaker 241, and the next side. D indicates the short-circuit point of the power distribution line 191.

However, in this IN, the protector fuse 14
Whether or not a, 14b, 14c are fused, protector fuse 1
4a, 14b, 14c are deteriorated, the instantaneous relay 22 is operating, and the motherboard air circuit breaker 23 is tripped. The short-circuit fault point is determined based on the operating conditions shown in the table, and logically, any of the determination means shown in Figures 2 to 5 is used to determine points B, 0, or various points A to D. Determine the point of short circuit fault. Note that the protector fuse will blow out if it exceeds the degraded area, but if it reaches the degraded area, it will need to be replaced.

(1) In case of short circuit accident at point B.

In this short circuit accident, as shown in the table above and FIG.
The AND condition is satisfied by the AND element 32 between the output of the OR element 31 in the non-trip state of No. 4 and the trip output of the motherboard air circuit breaker 23 due to the operation of the instantaneous relay 22, and
Each R phase and S phase.

All of the T-phase protector 14a is an AND element 3 with no melting.
When the AND condition of 3 is satisfied and both of these AND condition fulfillment signals are satisfied in the AND element 34, the AND condition of 8 is satisfied.
The point is determined to be a short-circuit accident. In other words, this short-circuit accident at point B occurs when the protector fuse 14a is unworked and unfused, and when the motherboard air circuit breaker 23 trips while each of the molded circuit breakers 241 to 244 does not trip, the 8 points are This is determined to be a short circuit accident.

(2) In case of 0 point short circuit accident.

This short circuit accident occurs when the non-trip OR element 31 output of the molded circuit breakers 241 to 244 of each of the distribution lines 191 to 14 and the trip output of the motherboard air circuit breaker 23 due to the operation of the instantaneous relay 22 are combined. The AND condition is satisfied by element 32, and each of the two phases of protector fuse 14a (R-8
, S-T phase.

AND element 41°42 in fused state between TR phase)
．． When any of the 43 outputs is output from the OR element 44, and an AND condition is established between the output of the AND element 32 and the output of the OR element 44 at the AND element 45, 8 points are determined to be a short-circuit accident.

(3) In the case of a short circuit accident at points A to D.

In this case, as is clear from the above table and the logic circuit shown in FIG. It is determined that a short circuit has occurred at point A.

However, it is assumed that the reverse power detection device 18a is in an operating state at this time. It goes without saying that consideration of the operating state of the reverse power detection device 18a is also taken into consideration in the determination of the B point short circuit accident and the 0 point short circuit accident.

In addition, when determining the above short circuit accident, there is no voltage on the secondary side of the network transformer due to a complete short circuit in the low voltage circuit, etc., and the reverse power detection device 1Ba, isb is detected.

18c may not operate, and the air circuit breaker 23 and molded circuit breakers 241 to 244 in the main connection section are connected to the distribution line 191 to
If a current-limiting type molded case circuit breaker is used in the event of a short-circuit on the It goes without saying that this assumes that the partial air circuit breakers may trip simultaneously.

Therefore, according to the configuration of the embodiment as described above, the mother connection part has the current transformer 21 with a built-in mother connection air breaker and the stationary instantaneous relay 22 with a built-in mother connection air breaker installed in the mother connection part. A partial air circuit breaker 23 is provided, and molded case circuit breakers 241 to 244 are provided on the power distribution lines 191 to 194 side and trip only by instantaneous elements.
By installing this, the protector fuses of all circuits can be detected, especially in the case of a B or 0 point short-circuit accident, by determining the Vi rating fault point including the presence or absence of melting of the protector fuse 14a of these circuit breakers and each line. The main air circuit breaker 23 can be tripped before entering the deterioration region, and even if the protector fuse blows, there is no problem in determining it because it blows after the main air circuit breaker trips.

In addition, in this device, the output of each component is logically divided into signals and extracted.

It is possible to reliably identify short-circuit accidents not only at the 0 point but also at various points in the system including the B points and the 0 points, which can greatly contribute to improving the safety of the spot network system and, by extension, maintenance.

In addition, in the above embodiment, short-circuit accidents at point B, point 0, and points A to D are determined, but from the table above and Figure 4, short-circuit accidents at point D as well as point A are determined separately. Needless to say, it can be determined. Further, although the above embodiment has been explained using a logical circuit, short-circuit failure points in various parts of the system can be determined by processing based on the processing routine shown in FIG. 5 using a microcomputer. That is, as is clear from the above table, it is determined whether any of the molded circuit breakers 241 to 244 has tripped or not, and if any of the molded circuit breakers 241 to 244 has tripped, D It is determined that the point is short-circuited, and when there is no trip, the process moves to step S2, and it is determined whether or not the main connection air circuit breaker 23 is not tripped, and if it is not tripped, it is determined that the A-point short circuit accident has occurred. Further, when the mother air circuit breaker 23 is tripped, the process moves to step S3, and it is determined whether or not the protector fuse 14a of any two of the three phases has blown. It is determined that there is a point short circuit, and if there is no melting, it is determined that there is an 8 point short circuit. Furthermore, although the above embodiment has been described based on the case of three phases, the R phase to eight phase protector fuses 14a are blown out, the S phase to
Since an output is generated when either the T-phase protector fuse 14a is blown or the T-phase-R-phase protector fuse 14a is blown, it can be similarly applied to a two-phase case. Further, although the description has been made regarding the line 11a, the same applies to lines 1m11b and 11c. In addition, the present invention can be implemented with various modifications without departing from the gist thereof.

[Effects of the Invention] As detailed above, the present invention provides the following effects.

First, in claim 1.2, not only can the short circuit accident point be determined before the result of the protector fuse, but also the short circuit accident between the network transformer secondary side and the protector fuse, which could not be determined in the past, and the protector fuse.
A short circuit accident at any point between the mother connecting parts can be accurately determined.

Further, in claim 3, it is possible to quickly and reliably determine the point of a short-circuit accident in each part of the system from a comprehensive viewpoint, contributing to the improvement of the efficiency and reliability of accident recovery work and system operation.

[Brief explanation of the drawing]

Figures 1 to 5 are shown to explain an embodiment of the short-circuit fault point discriminating device for a spot network system according to the present invention, and Figure 1 is a system diagram of a three-line bus split type spot network system. , Figures 2 to 4
The figure is a block diagram for logically determining each short-circuit fault point, and FIG. 5 is a flowchart for processing the short-circuit fault points using software. 11a, 11b, 11C--Line, 12a, 12b, 12c...-Oshoroki, 13a, 1
3b, 13G--Network transformer, 14a, 14
b, 14c...Protector fuse, 16a, 16b
, 16cm... Protector circuit breaker, 17... Network bus bar, 18a, 18b, 1 BC... Reverse power detection device, 19
1-194... Distribution line, 21... Current transformer, 22...
・Momentary relay, 23...Mother air circuit breaker, 241~
244...Made-in circuit breaker. Applicant's agent Patent attorney Suzue Takehiko EXζ 1 Figure 2 Figure 3 B Figure 5

Claims (3)

[Claims] (1) In a bus-split spot network in which primary disconnectors, network transformers, protector fuses, protector circuit breakers, etc. are individually connected to N (N is an integer) lines, stationary lines connected serially to the bus section are an air circuit breaker with a built-in instantaneous relay, a molded case breaker installed in the power distribution path from the main unit to the load side, the molded case breaker not tripped, the protector fuse not blown, and A short-circuit fault point of a spot network system, comprising short-circuit fault point determining means for determining that a short-circuit fault has occurred between the secondary side of a network transformer and a protector fuse when the air circuit breaker trips. Discrimination device. (2) In a bus-split spot network in which primary disconnectors, network transformers, protector fuses, protector circuit breakers, etc. are individually connected to N (N is an integer) lines, stationary lines connected serially to the bus section An air circuit breaker with a built-in instantaneous relay, a molded circuit breaker installed in the power distribution path from the main unit to the load side, and the molded circuit breaker is not tripped and at least two phase protector fuses are blown. and a short circuit fault point determining means for determining that a short circuit fault has occurred at any point in the protector fuse-mother link when the air circuit breaker trips. Short circuit failure point determination device. (3) In a bus-split spot network in which primary disconnectors, network transformers, protector fuses, protector circuit breakers, etc. are individually connected to N (N is an integer) circuits, the stationary busbars are serially connected to the bus section. Air circuit breakers with built-in instantaneous relays, molded circuit breakers installed on the power distribution path from the motherboard to the load side, the operating status of these air circuit breakers and molded circuit breakers, and protector fuses for each phase. A short-circuit fault point discriminating device for a spot network, comprising a short-circuit point discriminating means for determining short-circuit faults at various points in the system by logically dividing and extracting signals such as the presence or absence of melting.