JPH099496A - Spot network substation equipment - Google Patents

Abstract

(57) [Abstract] [Purpose] The reverse current interruption operation of the network protector is secured, the heat generation amount of the iron core of the spot network transformer is suppressed, and the transformer and the cooler are made compact to reduce the spot network receiver. Provide substation equipment. [Configuration] Spot network transformers 5a, 5b, 5c respectively connected to a plurality of supply side systems, and network protectors 14a, 14b, 14c respectively connected to secondary sides of the spot network transformers, At the time of an accident or opening of the supply side system, the network protector is operated by detecting a reverse current, and the power supply is supplied from the supply side system by disconnecting the accident point or the open system without power failure on the load side. In the spot network power receiving and transforming equipment 3, the resistors 12a, 12 are connected to the three-phase line between the spot protector and the network protector.
b and 12c are connected to a delta or star.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spot network power receiving and transforming facility.

[0002]

2. Description of the Related Art A system diagram of a conventional spot network power receiving system is shown in FIG. In FIG. 5, the spot network power receiving equipment 3 receives power from bus lines 2a, 2b, 2c of three lines which are connected to the supply side system and are supplied via distribution breakers 1a, 1b, 1c. 2 of 3 busbars
a, 2b, 2c are branched from the respective lines, and disconnecting switches 4a, 4b, 4c for power reception are connected, and spot network transformers 5a, 5 are connected to the output side of these disconnecting devices, respectively.
b and 5c are connected. Secondary sides of the spot network transformers 5a, 5b, 5c are connected to a common network bus 8 via network protectors 14a, 14b, 14c, respectively, and branched from this network bus 8 to branch into a plurality of indoor loads 9 Is powered.
The network protectors 14a, 14b, 14c
Are protector fuses 6a, 6b, 6c, protector breakers 7a, 7b, 7c, network relays 15a, 15b, 15c and current transformers 16a, 16b, respectively.
16c and other accessories not shown.

In the above spot network power receiving system, for example, when a ground fault occurs at the fault point 10c of the power supply system on the supply side, first the distribution breaker 1 of the bus 2c at which the fault occurred.
c is opened, and the bus bar 2c is disconnected from the power supply side. However, since the protector circuit breakers 7a, 7b, 7c are in the closed state, the network bus bar 8 is the remaining healthy bus bar 2a,
Since the power continues to be supplied from 2b, the reverse current 11 is disconnected from the above-mentioned power source through the protector circuit breaker 7c through the network bus 8.
Is supplied to. In order to prevent this reverse current 11, the network relay 15c senses the reverse current 11 with the help of a current transformer 16c and an auxiliary device (not shown) of the network protector 14c and shuts off the protector breaker 7c. As the reverse current 11 at this time, the vector sum of the charging current of the bus 2c and the exciting current of the spot network transformer 5c flows, but the charging current of the bus 2c is so small that it can be ignored as compared with the exciting current. In this case, it is necessary to operate the network protector 14c only by the exciting current of the spot network transformer 5c. Therefore, in general, spot network transformers 5a, 5b,
When 5c is excited from the secondary side at a voltage of 90% of the rated voltage, it is designed to obtain an exciting current effective component of 0.1% or more of the rated load current of the secondary side. In this case, the network protector 14c Detects the reverse current and enables the breaking operation.

[0004]

However, in such a structure, an active portion of the exciting current of 0.1% or more of the rated load current is obtained, and the distribution breaker of the one bus of the supply side system is opened. Network protector 14
In order for a, 14b, 14c to detect the reverse current and enable the breaking operation, it is necessary to use the spot core transformers 5a, 5b, 5c of the iron core using the iron core material with a large iron loss. As a result, the size of the transformer becomes large and the generated loss becomes large, so that the size of the cooler of the spot network transformers 5a, 5b, 5c becomes large.

Therefore, an object of the present invention is to provide a spot network transformer having a small iron loss, a compact outer size and a compact cooler, and a network protector that detects a reverse current and is reliable. It is to be able to perform the shutoff operation.

[0006]

According to the present invention, there are provided spot network transformers respectively connected to a plurality of supply side systems, and network protectors respectively connected to the secondary sides of these spot network transformers. In the spot network power receiving and transforming facility that supplies power from the supply side system without detecting a reverse current and operating the network protector when the supply side system has an accident or opening, and operating the network protector, the resistor is used. Is connected to a three-phase line between the spot network transformer and the network protector. Further, the resistor is housed in a box provided on the side wall of the spot network transformer, or the resistor is housed in a bus duct of the secondary side system of the spot network transformer.

[0007]

With this structure, the following actions can be obtained. Exciting 0.1% or more of the rated load current of the spot network transformers 5a, 5b, 5c by connecting the resistor in parallel to the line between the secondary side of the spot network transformer and the network protector for reverse current detection. A load loss equivalent to the effective current can be generated in the resistor.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a system diagram of an embodiment of the spot network power receiving and transforming equipment of the present invention. FIG. 2 shows details of a resistor portion for one system of the spot network power receiving and transforming system of the present invention. In FIG. 1, the spot network transformers 5a, 5b, 5c of the spot network substation equipment 3
The resistors 12a, 12b, and 12c are connected in three phases to the lines between the network protectors 14a, 14b, and 14c, respectively, as shown in FIG.
b and 13c are provided. The resistors 13a, 13b, 13c are spot network transformers 5a, 5b, 5 when the voltage of 90% of the rated voltage of the network bus 8 is applied.
0.1% or more of the rated load current of c is the resistors 13a, 13
The resistance value is set so as to flow to b and 13c. Since other configurations are the same as those of the conventional example shown in FIG. 5, description of the configurations will be omitted. FIG. 2A shows a resistor 1 for one system.
FIG. 2B shows a case in which 3a is configured by a triangular connection.
An example of a star connection is shown below.

In the spot network power receiving and transforming system, when a ground fault occurs at the fault point 10c of the power supply system, first, the distribution breaker 1c of the bus 2c in which the fault has occurred is opened. At this time, the protector circuit breaker 7c on the stop line side is passed from the remaining sound busbars 2a and 2b through the network busbar 8.
Reverse current 11 is supplied via the
Reverse current 11 is supplied to sound c from healthy 2a and 2b. At this time, the rated voltage of the network bus 8 is applied to the resistor 13c from another sound line, and the load current of 0.1% or more of the rated load current flows through the resistor 13c. That is, since the reverse current 11 necessary for surely performing the reverse current interruption operation of the network protector 14c is generated in the resistor 13c, the effective portion of the exciting current of the spot network transformer 5c may be a small value. Therefore, a good quality iron core material can be used for the iron core of the spot network transformer 5c, so that the iron core can be designed to have a small size and a small iron loss. Further, the resistors 13a, 13b, 13c shown in FIG. 2 may be housed in a box 13a provided on the side wall of the spot network transformer 5a, like the spot network power receiving and transforming equipment 3 shown in FIG.
Alternatively, as shown in FIG. 4, the bus duct 17 of the secondary side system
By accommodating it inside, the spot network power receiving and transforming equipment 3 can be downsized.

[0010]

As described above, according to the present invention, the following effects can be obtained. A resistor can generate an effective component current of 0.1% or more of the rated load current required for the reverse current cutoff operation of the network protector. Therefore, it is not necessary to increase the iron loss of the spot network transformer, the iron core can be made smaller, the size and shape of the spot network transformer can be made smaller, and a compact spot network transformer having a small cooler can be obtained. In addition, because this resistor can be stored in the box provided on the side wall of the spot network transformer or in the bus duct of the secondary side system of the spot network transformer, there is no restriction on the place where the resistor is installed. A compact spot network power receiving and transforming facility in which a resistor is provided in the surplus space can be provided.

[Brief description of drawings]

FIG. 1 shows a system diagram of an embodiment of a spot network power receiving facility of the present invention.

FIG. 2 is a wiring diagram of a resistor portion for one system of the spot network power receiving equipment of the present invention.

FIG. 3 is a diagram showing an embodiment in which a resistor portion of the spot network receiving / converting equipment of the present invention is housed in a side wall portion of the spot network transformer.

FIG. 4 is a diagram showing an embodiment in which the resistor part of the spot network receiving / converting equipment of the present invention is housed in the secondary side bus duct of the spot network transformer.

FIG. 5 is a system diagram showing an example of a conventional spot network power receiving and transforming facility.

[Explanation of symbols]

 1a, 1b, 1c Distribution breaker 2a, 2b, 2c Bus 3 Spot network power receiving equipment 4a, 4b, 4c Disconnector 5a, 5b, 5c Spot network transformer 6a, 6b, 6c Protector fuse 7a, 7b, 7c Protector breaker 8 network bus 9 premises load 10c accident point 11 reverse current 12a, 12b, 12c resistor 13a, 13b, 13c resistor 14a, 14b, 14c network protector 15a, 15b, 15c network relay 16a, 16b, 16c current transformer 17 bus duct

Claims (3)

[Claims] 1. A spot network transformer connected to each of a plurality of supply side systems, and a network protector connected to a secondary side of each of the spot network transformers. Sometimes, by operating the network protector by detecting a reverse current, without interrupting the load side, the accident point or disconnecting the open system, in the spot network power receiving and transforming equipment that supplies power from the supply side system, A spot network power receiving and transforming facility, wherein a resistor having a resistor connected to a delta or a star is connected to a three-phase line between the spot network transformer and the network protector. 2. The spot network substation equipment according to claim 1, wherein the resistor is housed in a box provided on a side wall of the spot network transformer. 3. The spot network power receiving and transforming equipment according to claim 1, wherein the resistor is housed in a bus duct of a secondary side system of the spot network transformer.