JPH02299420A - Control device of switch - Google Patents

Abstract

PURPOSE:To avoid the malfunction of a switch when judging if a over-current relay is or not, by providing an function discrimination means in which the overcurrent is judged to exist when it is discriminated that no trip coil is detected and on the other hand, the function is judged abnormal when it is discriminated that an overcurrent detection relay is ON. CONSTITUTION:With an overcurrent detection relay 18 ON, if no trip coil 23 is connected to a voltage circuit 19, it is determined that the overcurrent is detected, and if the trip coil 23 is connected, it is determined that the action is abnormal. In the former case, the overcurrent is detected in a three-phase bus 2, the contact of a relay X is switched from (b) to (a) and a trip coil circuit 19 is opened. As it gets in an SO function, the overcurrent detection relay 18 is OFF, a trip relay contact 22 is ON if service interruption is ascertained, and the driving current is caused to flow to the trip coil 23 to interrupt the switch. In the latter case, as no overcurrent is detected, no contact of the relay X will act and the trip coil 23 remains connected to the voltage circuit 19, so that it is determined that the action is abnormal.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application This invention relates to a switch control device that detects excessive current in a three-phase bus and shuts off the switch of the three-phase bus.

(b) Conventional technology In general, the device is connected to a three-phase load, detects excessive current and ground fault current, and when the ground fault current exceeds a predetermined level, current is applied to the trip coil to disconnect the switch. In addition, if an overcurrent is detected, the SOG (Storage 0 Vercure
nt Ground) type switch control device. Conventionally, this type of switch control device has a trip coil circuit consisting of a trip coil, a trip coil drive power source, a trip relay contact for connecting the trip coil drive power source to the trip coil, an overcurrent detection relay, and an overcurrent detection relay. The trip coil circuit is closed, and the overcurrent detection relay is turned on as a closed circuit in response to overcurrent detection on the three-phase bus.
When an overcurrent on the three-phase bus is detected, the switching circuit is activated to turn the overcurrent detection relay on.
NL, when a power outage occurs due to overcurrent detection, the overcurrent detection relay is set to 0FFL, and when it is confirmed that a power outage has occurred, the above trip relay contact is turned ON to flow a tripping current to the trip coil, and the customer of the three-phase bus The switch on the side had been shut off.

(c) Problems to be Solved by the Invention In the conventional switch control device described above, the overcurrent detection relay turns ON and then turns OFF to activate the trip coil when a power outage is confirmed. The switch was shut off. Therefore, even if the overcurrent detection relay does not detect an overcurrent but malfunctions and a power failure occurs, there is a risk that the switch will be shut off and malfunction. For example, the external relay contact cable that makes up the switching circuit between the trip coil circuit and the overcurrent detection relay may use a multi-core cable, and water can enter the cable and reduce the impedance of the contact part. However, due to this decrease, even though the switching circuit is not switching, the overcurrent detection relay becomes ONL, and when a normal power outage occurs, the trip coil is operated and the switch is cut off.

This invention was made in view of the above problem, and only when an overcurrent flows and a power outage occurs as a result, the trip coil is activated to shut off the switch, thereby avoiding malfunction. The purpose of the present invention is to provide a switch control device that obtains the following.

(d) Means and operation for solving the problems The switch control device of the present invention includes a trip coil, a trip coil drive power source, and a trip relay contact for connecting the trip coil drive power source to the trip coil. a trip coil circuit; a switching circuit that normally makes the trip coil circuit a closed circuit and makes an overcurrent detection relay a closed circuit in response to overcurrent detection of the three-phase bus; and a trip coil detection circuit that detects whether the overcurrent detection relay is turned on, and drives the trip coil and shuts off a three-phase bus switch in response to turning on of the overcurrent detection relay. a means for determining whether or not the trip coil detection circuit detects the detection; a means for determining whether or not the trip coil detection circuit detects the detection; and a means for determining whether or not the trip coil detection circuit detects the detection; An operation determining means is provided for determining an abnormal operation based on whether or not a trip coil is detected.

In this switch control device, when an overcurrent flows in the three-phase bus, the switching circuit is activated by the detection output from the overcurrent detector.
When the overcurrent detection relay is turned on, the trip coil circuit is opened and there is no output from the trip coil detection circuit. Therefore, the overcurrent detection operation is determined by the output that determines whether the overcurrent detection relay is ON or the trip coil detection circuit has no output, and the trip relay is ON or ON after a power outage occurs.
Drive current flows through the trip coil and the switch is shut off.

On the other hand, if the overcurrent detection relay is turned on due to a failure in the switching circuit, etc. while normal current is flowing through the three-phase bus, the trip coil circuit remains in a closed loop, so there is an output from the trip coil detection circuit. In this case, abnormal operation is determined. Even if a power outage occurs in this state, it will not be determined as an overcurrent and the trip coil will not operate.

(E) Examples The present invention will be explained in more detail with reference to Examples below.

FIG. 2 is a block diagram of an SOG type switch control device in which the present invention is implemented. In the figure, a 6600V power supply system 1 is connected to a zero-sequence current detector (zero-sequence current transformer) 2 and a zero-sequence voltage detector 3, which detect zero-sequence current and zero-sequence voltage, respectively. It looks like this. The zero-sequence current detected by the zero-sequence current detector 2 is converted into a voltage signal,
The CPU via the human quadrant 21 and the signal processing circuit 20
4 is man-powered. Further, the zero-phase voltage detected by the zero-phase voltage detector 3 is input to the CPU 4 via the voltage converter 3a, the input voltage transformer 31, and the signal processing circuit 30. The signal processing circuits 20 and 30 each include an over-input protection circuit, a test switching circuit, a filter, an effective value smoothing circuit, a level conversion circuit, and a conversion circuit.

The setting circuit 5 has a setting value of zero-sequence current I0, zero-sequence current ■. This is a circuit for setting the setting value and setting time T of D.
The C test switch 6a is a manual switch for performing a ground fault test, and the SO test switch 6b is a manual switch for performing an overcurrent test. The display section 7 includes a V0 level display, a power supply display, and a forecast display. The output unit 8 is equipped with a DC display based on ground fault detection and an SO display based on overcurrent, and also includes a relay for tripping in the event of a ground fault, a relay for tripping in the event of overcurrent, a forecasting relay, an abnormality relay, etc. It is equipped with

The CPU 4 also includes a test signal generation circuit 9 and a test circuit.
A diagnostic circuit 10 and an OC storage circuit 26 are attached.

Furthermore, this switch control device serves as its own power supply unit.
It includes a filter circuit 11, a constant voltage circuit 12, and constant voltage level conversion circuits 13 and 14. A commercial power supply voltage is applied to terminals p, , and Pz.

15 is an overcurrent detection circuit, 16 is a trip coil circuit, and 17 is a trip coil detection circuit, which are circuit parts related to the present invention. The overcurrent detection circuit 15 has a connection terminal ■. , ■5, including the overcurrent detection relay 1, one end of the overcurrent detection relay 18 is connected to the connecting terminal vb, and the connecting terminal ■ is externally connected to the normally open contact a of the relay X, as shown in FIG. The connection terminal VC is connected to the common contact C of the relay X.

The trip coil circuit 16 includes a resistor R1 and a capacitor CI.
, diode d3, and resistor R2.
, connection terminals v, ,Vb, a trip relay contact 22 connected between the connection terminal 1 and the drive power circuit 19, and a trip coil 23. The capacitor C8 of the drive power supply circuit 19 is charged with the voltage from the commercial power supply terminals P+ and P2 via the diode d, and is maintained even in the event of a power outage. The trip relay contact 22 is turned on when the trip relay of the output relay circuit 8 is turned on.

As shown in FIG. 3, the trip coil 23 is connected between the normally closed contact of the relay X and the connection terminal V□.

The trip coil detection circuit 17 is connected to the connection terminal ■.

and the power supply circuit 24. The power supply circuit 24, like the drive power supply circuit 19, charges a capacitor C2 with a commercial voltage applied to the terminals P+ and P2 to obtain the required power supply voltage. Trip coil detection circuit 1
7 includes a photocoupler light-emitting diode 25, and when a trip coil 23 is connected between connection terminals V, VC, a certain amount of current flows from the power supply circuit 24, and the photocoupler light-emitting diode 25 emits light to the CPU 4. Informs that the trip coil 23 is connected. If the trip coil 23 is not connected, a closed circuit will not be formed and the light emitting diode 25 will not light up.

FIG. 3 is a schematic diagram of a three-phase bus system for explaining overcurrent operation of the SOG switch control device.

Electric power is supplied from the substation 32 via a first switch 33 and a second switch 34 provided on the customer side.

When an overcurrent flows through the three-phase bus, the overcurrent detector 35 detects this and shuts off the main switch 33, and the relay X is turned ONL and the relay contact is turned on to the terminal a side.

Next, the overcurrent operation of the switch control device of the above embodiment will be explained with reference to the flowchart shown in FIG.

When the CPU 4 starts this overcurrent detection operation, it first determines whether the trip coil 23 is connected based on the output of the trip detection circuit 17 (step 5TI). When the trip coil 23 is connected, a small amount of current flows to the trip coil 23 via the trip coil detection circuit 17.
The trip coil is present, and the step STI judgment is YE.
It becomes S. Next, it is determined whether the overcurrent detection relay 18 is ON or not, that is, whether ON is stored in the OC storage circuit 11 (Step 5T2). If this determination is NO, the process moves directly to other processing. If the determination is YES in step ST2, after a certain time lag (step 5T3),
It is determined whether the trip coil 23 is not connected (step 5T4). An overcurrent flows through the three-phase bus 2,
When this is detected and the contact of relay
If this judgment is YES, it is determined that there is an overcurrent (Step 5T5)
, the process moves to So operation processing, and the overcurrent detection relay 18 is turned off.
When a power outage is confirmed, the trip relay is turned ON (step ST6.5T7), the relay contact 22 is turned ON, the drive current is applied to the trip coil 23, and the switch 34 is cut off.

On the other hand, in the determination in step ST2, for example, the connection terminal ■1,
If the overcurrent detection relay 18 is turned on due to a drop in the impedance between VC and YES, no overcurrent is detected and the relay If there is a detection output, the determination in step ST4 is NO. And V, -V for abnormal display etc. Performs abnormality processing (step 5)
T9), move on to other processing. In this case, in the event of a normal power outage after the overcurrent detection relay 18 is turned on, the trip relay 22 is not turned on and the switch 34 is not cut off.

(f) Effects of the Invention According to this invention, it is determined whether the overcurrent detection relay is turned on or not, and it is also determined whether the trip coil detection circuit is detected, and there is no trip coil detected when it is determined that the overcurrent detection relay is ON. It is determined that an overcurrent is detected when the overcurrent detection relay is ON, and an abnormal operation is determined when the trip coil is detected when the overcurrent detection relay is ON. Therefore, the switch can be shut off only when an overcurrent is truly detected, preventing malfunction. It can be avoided.

[Brief explanation of the drawing]

FIG. 1 is a flow diagram for explaining the overcurrent detection operation of an SOG switch control device according to an embodiment of the present invention, and FIG.
FIG. 3, a block diagram of the SOG switch control device of the same embodiment, is a circuit diagram showing a bus system to which the SOG switch control device is connected. 2: Three-phase bus, 4: CPU. 16: trip coil circuit, 17: trip coil detection circuit, 18: overcurrent detection relay, 19 nitrite tube drive power supply, 22 nitrite tube relay one contact, 23 nitrite tube coil. Patent Applicant Tateishi Electric Co., Ltd. Agent Patent Attorney Shigeru Nakamura Figure 1

Claims (1)

[Claims] (1) A trip coil, a trip coil drive power source,
A trip coil circuit includes a trip relay contact for connecting the trip coil drive power source to the trip coil, and the trip coil circuit is normally closed, and overcurrent is detected in response to overcurrent detection of the three-phase bus. The switching circuit includes a switching circuit that makes the relay a closed circuit, and a trip coil detection circuit that detects a closed circuit state of the trip coil circuit, and drives the trip coil in response to turning on of the overcurrent detection relay, and drives the trip coil in response to turning on the overcurrent detection relay. A switch control device that shuts off a busbar switch, comprising means for determining whether or not the overcurrent detection relay is turned on, means for determining whether detection is detected by the trip coil detection circuit, and determining whether the overcurrent detection relay is turned on. The switch control is characterized by comprising an operation determining means that determines overcurrent detection when determining that a trip coil is not detected, and determines an abnormal operation when determining that a trip coil is not detected when determining that an overcurrent detection relay is ON. Device.