JPH07108057B2 - Fault detection device for distribution lines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention detects a faulty section of a distribution line by detecting which section of a plurality of sections of the distribution line has an accident and disconnecting the faulty section. It relates to the device.

(Prior Art) Although it is desirable to find a faulty section and retransmit power to a healthy section promptly in an electric line, a conventional faulty section detecting device for a distribution line is for grounding on a bus L as shown in FIG. Transformer GPT,
In addition, the zero-phase current transformer ZCT is attached to each of the distribution lines 1a to 1c, and the grounding transformer GPT and the zero-phase current transformer ZCT are connected to the ground fault direction relay DGR, causing a ground fault. Then, when a fault current flows, this ground fault direction relay DGR causes zero-phase current transformer Z
The fault circuit is selected and discriminated based on the fault current output from the CT and the zero-phase voltage Vo output from the grounding transformer GPT, and the breaker CB of the fault distribution line is activated by the operation of the secondary bus ground fault overvoltage relay OVGR. When the circuit was opened, the section switches SS in all sections were automatically opened.

To detect an accident section, first turn on the circuit breaker CB and sequentially close the section switches SS provided for each section, and the zero phase when the section switches SS before and after the accident section are closed. The output of the current transformer ZCT was discriminated by a discriminator (not shown) to detect the faulty section.

(Problems to be Solved by the Invention) However, in the above-mentioned conventional fault detection device for a distribution line, when the switch section SS is closed before and after the fault segment, a fault current flows again in the fault segment. Was opened, and all the sections were cut off, making power consumers inconvenient.

Also, grounding transformers (GPT), zero-phase current transformers (ZCT) and their ground fault direction relays (DGR) installed on the busbars are installed in each slave station to check whether there is a ground fault in each slave station. A method of detecting and detecting the ground fault accident section from the information can be considered, but this method requires installation of GPT, ZCT, DGR for each slave station, which makes the equipment on the slave station side expensive. Will end up.

The object of the present invention is to solve the above problems, when a ground fault accident or the like occurs, quickly determine and disconnect the accident section, eliminate the power outage other than the accident section, or only when the accident occurs. An object of the present invention is to provide an accident section detection device in a distribution line that can be used for a short time power outage and can reduce the cost of the device on the slave station side without the need to install GPT, ZCT, DGR for each slave station.

(Means for Solving the Problem) In order to achieve the above object, the present invention provides a phase difference (θvo-ia) between a zero-phase voltage (Vo) and a phase component (Va or Ia) in a master station.
Or θvo-va) and the zero-phase current (Io) and phase component (Va 'or Ia') in the slave station input via the communication device (5, 11).
And the phase difference (θio-va 'or θio-ia') are compared and calculated to find the phase difference (θvo-io) between the zero-phase voltage (Vo) and the zero-phase current (Io). In addition to detecting the ground fault accident section in the master station, it is configured to instruct the slave station in the section that has become the accident section to separate the accident section by opening and closing the classification switch (SS) in the slave station. .

(Operation) The present invention operates as follows by adopting the above means.

The zero-phase current and the phase component of the current or voltage detected by the detection means on each slave station side are input to the phase difference detection circuit on the slave station side, where the phase difference between the zero-phase current and the phase component is detected. The data is input to the arithmetic device and transmitted from each communication device on each slave station side to the communication device on the master station side. On the other hand, the zero-phase voltage and the current or the phase component of the voltage detected by the detection unit on the master station side are also input to the phase difference detection circuit on the master station side, where the phase difference is detected and the arithmetic unit on the master station side is detected. Entered in. On the master station side, the phase difference transmitted from the slave station side and the phase difference on the master station side are compared and calculated by a computing device, and the zero phase voltage and zero phase current of each slave station are calculated from the reference phase component. When a ground fault occurs, the phase difference changes on the slave station side before and after the accident section, so the changed section is detected by the arithmetic unit on the master station side. .

Then, an arithmetic circuit on the side of the master station sets a predetermined time (for example, 1
If a faulty section is detected within (seconds), the loop point switch is turned on at the command of the master station and the switches at both ends of the faulty section are opened to shut off the faulty section, Transmit power to distribution lines in healthy sections.

If the operation circuit on the master station side does not detect an accident section within the specified time, the circuit breaker is opened by the ground fault direction relay, and the breaker and each section open / close according to the command on the master station side. Turn on the switch and loop point switch to transmit power to healthy sections other than the accident section.

(Embodiment) An embodiment embodying the present invention will be described below with reference to FIGS. 1 to 3.

As shown on the left side of Fig. 1, on the substation side as the master station, the three-phase distribution lines 1a, 1b, 1c are connected to the grounding transformer as a zero-phase component detecting means for detecting the zero-phase voltage Vo. The device GPT and the zero-phase current transformer (ZCT) for detecting the zero-phase current Io are connected. In addition, the three-phase distribution lines 1a, 1b, 1c, the current transformer CT as a means for detecting the phase component of the parent station side of each phase
The a, CTb, and CTc are attached so that the phase currents Ia, Ib, and Ic of each distribution line can be detected. In this embodiment, the 1a phase current Ia is input to the phase difference detection circuit 2 described later.

The grounding transformer GPT and the current transformer CTa include a phase difference detection circuit 2 on the master station side for detecting a phase difference θvo-ia between the zero-phase voltage Vo and the phase current Ia of the 1a phase described above. Are connected. Further, a ground fault direction relay DGR is connected to the grounding transformer GPT and the zero-phase current transformer ZCT so that an accident occurrence signal can be output to the arithmetic unit 4 on the master station side described below.

The processing unit 4 is a central processing unit as shown in FIG.
It is composed of a CPU, a memory RAM, a digital input DI, a digital output DO, and an address / data bus BUS. Then, to the digital input DI, a signal from the phase difference detection circuit 2, an ON / OFF signal for transmitting whether or not a ground fault has occurred from the ground fault direction relay DGR, and further ON of the circuit breaker CB.・ The OFF state is input, and the circuit breaker CB is turned ON / OFF by the output signal of the digital output DO.

Further, the address / data bus BUS is connected to a master station side communication device 5 which receives a signal from a slave station side communication device 11 described below. In addition, this communication device 5
For example, it is possible to communicate with the control device 6 of the sales office by a communication line 12 such as an optical fiber or a lead wire or wirelessly.

On the other hand, as shown in the right side of FIG. 1, the three-phase distribution lines 1a, 1b, 1c in each section of the distribution lines 1a to 1c respectively include current transformers CTa, CTb, as the means for detecting the phase component of each phase. A CTc is attached so that the phase currents Ia ′, Ib ′, Ic ′ of each distribution line can be detected.

Each of the current transformers CTa, CTb, CTc is connected to the zero-phase current detection circuit 7, and the zero-phase current Io is calculated here. In this embodiment, the current transformers CTa to CTc and the zero-phase current detection circuit 7 constitute a zero-phase component detecting means M.

The zero-phase current detection circuit 7 and one of the three phases, for example, the current transformer CTa of the distribution line 1a, have a zero-phase current Io and a 1a-phase current Ia.
A phase difference detection circuit 8 on the slave station side for detecting a phase difference θio-ia 'with a'is connected. Further, an Io level detector 9 for detecting the level of the zero-phase current is connected to the zero-phase current detection circuit 7 and is turned on or off depending on the magnitude of the zero-phase current Io.
The Io level signal for FF is input to the arithmetic unit 10 on the slave station side described below.

As shown in FIG. 3, the arithmetic unit 10 is configured in the same manner as the arithmetic unit 4 on the master station side described above, and the phase difference detection circuit 8 is connected to the digital input DI, and the zero phase Io level detector 9 connected to the current detection circuit 7
ON / OFF signal output from the
The ON / OFF state of is input, and the section switch SS is turned on / off by the output signal of the digital output DO.

In addition, the communication device 11 on the slave station side is connected to the address / data bus BUS.
Are connected to each other, for example, a communication line 12 such as an optical fiber or a lead wire.
Is connected to the master station side communication device 5.

Next, the operation of the accident section detection device configured as described above will be described.

First, on the master station side, the zero-phase voltage Vo is detected by the grounding transformer GPT, the phase current Ia of the 1a phase is detected by the current transformer CTa, and the zero-phase voltage Vo and the phase current Ia are detected by the phase difference detection. The phase difference θvo-ia is calculated here by being input to the circuit 2, and the accident occurrence signal is input to the next arithmetic unit 4 by the phase difference θvo-ia and the ground fault direction relay DGR.

On the other hand, on the slave station side of the distribution line, the phase currents Ia ′ to Ic ′ of the respective phases are detected by the respective current transformers CTa to CTc, and the phase currents are input to the zero phase current detection circuit 7 and the zero phase currents are detected. Io is calculated. Then, the zero-phase current Io and the 1a-phase current Ia 'are input to the phase difference detection circuit 8, where the phase difference θio-ia' is calculated. Then, the phase difference θio-ia ′ and the Io level signal output from the Io level detector 9 are input to the arithmetic unit 10, and from there, the communication unit 11 passes the communication line 12 to the master station side communication unit 5. It is transmitted and input from the communication device 5 to the arithmetic unit 4 on the master station side. In this way, the arithmetic unit 4
The phase difference θvo-ia detected on the master station side and the phase difference θio-ia ′ detected on the slave station side are input to the
When 1a to 1c are in a healthy state, the OFF signal is input from the ground fault direction relay DGR on the master station side to the digital input DI, so the arithmetic unit 4 on the master station side does not operate.

On the other hand, if there is no ground fault on the slave station side,
Since the OFF signal from the Io level detector 9 is input to the digital input DI, the arithmetic unit 10 on the slave station side does not operate.

Now, for example, if a ground fault occurs in a section of the distribution line,
On the master station side, digital input D from the ground fault direction relay DGR
An accident occurrence signal is input to I and Io on each slave station side
Since the ON signal is inputted from the level detector 9 to the digital input DI, it becomes the reference from the phase difference .theta.vo-ia of the master station and the phase difference .theta.io-ia 'of each slave station mentioned above by the arithmetic unit 4 on the master station side. The subtraction operation is performed so as to remove the phases θia and θia ′ of the current component, and the zero-phase voltage Vo and the zero-phase current Io are obtained,
The phase difference θvo-io between the two is calculated. Then, since the phase difference θvo-io changes before and after the accident section, the phase difference of each slave station is sequentially detected on the master station side, and if there is a slave station with a changed phase difference, the slave station It is possible to confirm that an accident has occurred in the section with the slave station on the upstream side.

Further, in the above embodiment, the zero phase voltage Vo of the master station on the bus side and the phase component Ia of the current are used for the calculation of the phase difference θvo-io described above, so that each slave station has a phase current detecting means. Current transformer (C
It is sufficient to install only T), and therefore the device on the slave station side can be made inexpensive.

When the above-mentioned calculation processing time becomes a predetermined time (for example, 1 second) or longer, the calculation device 4 on the master station side turns off the breaker CB.
Signal or the OFF signal which is the delay signal of DGR is output, and the distribution line goes into a power failure state. After that, the circuit breaker CB and the classification switch SS are operated according to a command from the master station, and power is transmitted to a healthy section other than the accident section.

When the above-mentioned arithmetic processing time becomes less than a predetermined time (for example, 1 second), the loop point switch (not shown) is closed according to a command from the master station, and a segment switch sandwiching an accident section.
The SS is turned off and only the accident section is in the power failure state. In addition,
In this case, the accident section will be cut off within a predetermined time,
Circuit breaker CB does not open.

In the above-mentioned embodiment, by using the grounding transformer GPT installed in the building of the substation as a means for detecting the zero-phase component in the master station, the slave station side, in terms of insulation reliability outdoors. The reliability can be improved as compared with the case where a GPT having a difficulty is provided.

The present invention can also be embodied as follows.

(1) In the above embodiment, the ground fault direction relay DG on the master station side
Although the ON / OFF signal from R is input to the arithmetic unit 4, instead of this, the zero-phase current Io from the zero-phase current transformer ZCT separately provided on the master station side as shown in FIG. 1 is used. ON input to the Io level detector 15 shown in FIG. 4 and output from this detector 15
-Configure to input the OFF signal to the arithmetic unit 4, and configure the device on the slave station side in the same way as in Fig. 3.

(2) As shown in Fig. 5, the reference phase current on the master station side
Instead of Ia, the transformer PT for instrument as a means of detecting the phase component
The phase voltage Va ′ detected by a is input to the phase difference detection circuit 2 and the phase difference θvo-va is output from the detection circuit 2. On the other hand, on the slave station side, instead of the current transformer CTa, as shown in FIG. 6, the phase voltage Va ′ from the instrument transformer PTa provided in each section is input to the phase difference detection circuit 8. The phase difference θio-va 'is output from the detection circuit 8.

(3) Instead of the ground fault direction relay DGR on the master station side shown in FIG. 5, ON / OFF signals from the Io level detector 15 should be input to the arithmetic unit 4.

As is clear from the embodiment shown in FIGS. 1 to 3 and the another example shown in FIG. 4 and the other examples shown in FIGS. 5 and 6, the phase difference detection circuit 2 on the master station side has zero The phase voltage Vo and the phase current Ia or the phase voltage Va are input, and their phase difference θvo−ia, θvo
-Va will be output.

Further, the zero phase current Io and the phase current Ia or the phase voltage Va ′ are input to the phase difference detection circuit 8 on the slave station side, and the phase difference θio between them is inputted.
-Ia 'or θio-va' will be output. Based on these phase difference information, the phase difference θvo-io for each slave station is calculated,
The ground fault accident section is detected as described above.

Effect of the Invention As described in detail above, the present invention quickly detects in which section of the distribution line a ground fault or the like has occurred, and eliminates the power outage of the distribution other than the accident section, or minimizes the number of times. Further, there is an effect that it is not necessary to install GPT, ZCT and DGR for each slave station and the cost of the device on the slave station side can be reduced.

[Brief description of drawings]

FIG. 1 is an electric block circuit diagram showing an embodiment of the accident section detection device of the present invention, FIG. 2 is an electric block circuit diagram of a computing device on the master station side and its connecting equipment, and FIG. 3 is a slave station side. FIG. 4 is an electrical block circuit diagram of the arithmetic unit and its connected equipment, FIG. 4 is an electrical block circuit diagram only on the master station side showing another embodiment of the present invention, and FIGS. 5 and 6 are further implementations of the present invention. FIG. 7 is an electric block circuit diagram showing a master station side and a slave station side showing an example, and FIG. 7 is an electric circuit diagram showing a conventional accident section detection device. 1a, 1b, 1c …… Distribution lines, 2 …… Phase difference detection circuit on the master station side,
4 ... Calculation device on the master station side, 5 ... Communication device on the master station side, 7
...... Slave station side zero phase current detection circuit, 8 ...... Slave station side phase difference detection circuit, 9 ...... Io level detector, 10 ...... Slave station side arithmetic unit, 11 ...... Slave station side communication Device, Vo ... Zero phase voltage (component), Io ... Zero phase current (component), Ia, Ia '... Phase current (component), Va, Va' ... Phase voltage (component), θvo-ia, θvo
−va, θio−va ′, θio−ia ′ …… Phase difference, SS …… Differential switch, GPT …… Grounding transformer, DGR …… Ground fault direction relay, ZCT …… Zero phase current transformer, CTa ~ CTc …… Phase current (component)
Current transformer as detection means, PTa to PTc ... Phase voltage (component)
Transformer for instrument as detecting means, M ... Current transformer CTa to CTc
Zero-phase current (component) detection means including a zero-phase current detection circuit 7 and the zero-phase current detection circuit 7.

Claims (1)

[Claims] 1. In a plurality of sections dividing the system of the three-phase distribution line (1a, 1b, 1c), one section serving as a master station has a zero-phase voltage of the three-phase distribution line (1a, 1b, 1c). (Vo), the detection means (GPT, PTa, CTa) of any one-phase voltage or current phase component (Va or Ia), the zero-phase voltage (Vo) and the phase component (Va)
Alternatively, the phase difference detection circuit (2) of Ia) is provided, and on the other hand, the three-phase distribution lines (1a, 1b, 1) are respectively provided in the other sections which are slave stations.
c) zero-phase current (Io), means (M, CTa, PTa) for detecting the phase component (Va 'or Ia') of the voltage or current in phase with the arbitrary one phase, and the zero-phase current (Io). Io) and phase component (V
a'or Ia ') phase difference detection circuit (8) is provided, and both phase difference detection circuits (2,8) are provided with arithmetic unit (4,10) and arithmetic unit (4,10) respectively. A communication device (5, 11) for connecting sections is provided, and a phase difference (θvo-ia or θvo-va) between the zero-phase voltage (Vo) and the phase component (Va or Ia) in the master station, The communication device (5,
Phase difference (θio-va 'or θio) between the zero-phase current (Io) and the phase component (Va' or Ia ') in the slave station input via 11).
-Ia ') is phase-computed and the phase difference (θvo-io) between the zero-phase voltage (Vo) and the zero-phase current (Io) is calculated. An apparatus for detecting a faulty section of a distribution line, characterized in that a faulty section of a power distribution line is configured to be instructed to a slave station in a section that has become a faulty section so as to open and close a section switch (SS) in the slave station to separate the faulty section.