KR102669339B1 - Gas Insulated Switchgear Overload trip device for DC motor - Google Patents

Abstract

The present invention relates to an overload trip device for a GIS DC motor, which detects the current flowing in the DC motor through a current transformer and manages the current value and fixed time by increasing or decreasing it to a predetermined size, thereby protecting the DC motor from unexpected lightning or overcurrent. It has the effect of stably protecting the power supply.

Description

Overload trip device for GIS DC motor {Gas Insulated Switchgear Overload trip device for DC motor}

The present invention relates to an overload trip device for a GIS DC motor. More specifically, it detects the load current supplied to a gas-insulated DC motor and trips a relay to protect the DC motor when the load current exceeds a preset value. This relates to an overload trip device for a GIS DC motor that can stably operate the GIS DC motor by being equipped with a microcomputer that transmits a control signal.

In general, motor failures are caused by circuit conditions such as disconnection of wiring, abnormalities in switches or protectors, or by overload that occurs during operation, high frequency starting, etc. Among these failure causes, an overload trip device is often used as a device to prevent motor damage caused by overload operation.

These trip devices are divided into three types according to the tripping method: thermal electronic, fully electronic, and electronic. The thermal electronic type uses a bimetal and an electromagnet, and the fully electronic type uses the power of the electromagnet of the Oil Dash pot to execute the trip. In the electronic method, the current flowing in each phase is detected by a CT (Current Transformer). In the case of AC power, after full-wave rectification in the rectifier circuit and conversion in the effective value conversion circuit, the phase with the maximum current is selected, and overcurrent or large current is selected. This is a method of opening and closing the switch by exciting it according to the maximum current and the signal of the time circuit when it flows through the load.

Recently, the electronic trip method is mainly used rather than the thermal electronic or fully electronic type, whose operating point changes significantly depending on the surrounding temperature.

As a related prior art, an overload relay for motor protection was disclosed in Korean Patent No. 10-0184349 (December 18, 1998).

In the prior art, in protecting the motor from overload or overcurrent, a current transformer (CT1, CT2 or any number) and a resistor (R23, R24) are arranged in parallel on the input side of the MCU (U1) to operate the OP amps (U2A, U2B). It is connected to the inverting input terminal, and a noise filter consisting of resistors (R8, R11) and condensers (C7, C8) is installed at the input terminal, and the output of the OP amplifier (U2A, U2B) is connected to the diode (D1). It is connected to the input side of the comparator (U2C) (U2D), and the output of the comparator is connected to the input terminals 11 and 12 of the MCU (U1), and the output side 13, 14, and 15 of the MCU (U1) Variable resistors (VR1, VR2, VR3) are connected between and ground to adjust OT, load, and automatic reset, and light emitting diodes (LED1, LED2) and trip relays (RL1, It is characterized by connecting RL2).

However, the above-mentioned prior art had the inconvenient problem that the magnitude of the current flowing into the motor could not be directly displayed, and the variable resistance had to be adjusted separately to the pickup setting value that sets the upper limit when abnormal current is drawn.

The present invention was created to solve the problems of the prior art as described above. The purpose of the present invention is to detect the inflow of lightning or overcurrent into a gas-insulated DC motor and immediately block it by detecting the pickup current, pickup time, and instantaneous current through software. We provide an overload trip device for GIS DC motors that is easy to set up and use, and displays the load that caused the accident on the display so that managers can respond quickly.

An overload trip device for a GIS DC motor according to the present invention to achieve the above object includes a power supply unit that supplies DC driving power; A current detection unit that detects the load current flowing in the GIS DC motor, converts the detected load current into voltage, and transmits it; a microcomputer that determines whether the voltage value input from the current detection unit is normal and outputs a control signal and status information; a setting input unit equipped with a tact switch for inputting threshold values of pickup current, pickup time, and instantaneous current stored in the microcomputer; a display unit provided with an FND and an LED indicating status information transmitted from the microcomputer; It is characterized by being provided with a relay output unit that drives the relay according to the control signal from the microcomputer.

The current detection unit is characterized by being provided with a first current transformer that detects the load current flowing in the first load and a second current transformer that detects the load current flowing in the second load.

The microcom adjusts the pickup current in the range of 1.0 to 5.0 A in increments of 0.1 A through the setting input unit, the pickup time in increments of 0.1 Sec in the range of 0.1 to 10.0 Sec, and the instantaneous current is 3.0. It is characterized by adjusting the value in the range of 20.0 A to 20.0 A in increments of 0.5 A, and controlling the relay to be driven at a fixed time.

The status information includes load current detection information detected by the first and second current transformers, excess information indicating whether the detection information exceeds a preset pickup current and pickup time, and control according to the excess information. It is characterized by including trip information to display the trip and pickup status of the GIS DC motor.

The relay output unit is characterized in that it is provided with an alarm branch unit that branches the control signal and supplies it to an alarm.

As such, the overload trip device for GIS DC motor according to the present invention has the following effects.

First, the current detection unit detects the load current flowing in the load, converts it into voltage and inputs it to the microcomputer, and the microcom determines whether the load current flowing in the load is normal based on the preset pickup current and determines the trip status of the relay. By controlling, damage to the load due to overcurrent can be prevented,

Second, the microcomputer is set to adjust the pickup current in 0.1A units, the pickup time in 0.1Sec units, and the instantaneous current in 0.5A units, so that the operating environment of the load can be precisely adjusted and controlled.

Third, a display is provided that displays detection information, excess information, and trip information, which are status information related to the first and second current transformers, relays, and loads, providing an environment where managers can quickly identify and respond to the cause of a failure. There is an effect.

Figure 1 is a basic circuit diagram of an overload relay for motor protection according to the prior art,
Figure 2 is a block diagram of an overload trip device for a GIS DC motor according to the present invention;
Figure 3 is a diagram showing the display unit and setting input unit of the overload trip device for GIS DC motor according to the present invention.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the attached drawings.

As shown in Figures 2 and 3, the overload trip device for a GIS DC motor according to the present invention includes a power supply unit 10, a current detection unit 20, a microcomputer 30, a setting input unit 40, and a display unit ( 50) and a relay output unit 60 are provided.

Here, the GIS DC motor is an abbreviation for Gas Insulated Switchgear and is called a gas insulated switchgear, and is driven by power supplied from the power supply unit 10 at DC 125V with an error of ±10%.

That is, the power supply unit 10 supplies DC driving power, the current detection unit 20 detects the load current flowing to the GIS DC motor, and the microcomputer 30 determines whether the load current is within the normal range. Status information and control signals are output to the display unit 50 and the relay output unit 60.

At this time, the normal range is set by the pickup current, pickup time, and instantaneous current of the load through the tact switch 41 of the setting input unit 40, and the microcomputer 30 determines whether it is normal according to the setting range and detects an abnormality. When recognized as a signal, a control signal is transmitted to the relay output unit 60 to trip the relay.

Meanwhile, the display unit 50 is equipped with an FND 51 and an LED 52 to display status information transmitted from the microcomputer 30.

In addition, the current detection unit 20 is provided with a first current transformer 21 that detects the load current flowing in the first load and a second current transformer 22 that detects the load current flowing in the second load, so that the two loads It is possible to monitor the device and reliably block the inflow of abnormal power.

The microcomputer 30 adjusts the pickup current in the setting input unit 40 in the range of 1.0 to 5.0 A in increments of 0.1 A, and the pickup time in the range of 0.1 to 10.0 Sec in increments of 0.1 Sec. , the instantaneous current is adjusted in the range of 3.0 to 20.0 A in increments of 0.5 A, and the relay is controlled to be driven at a fixed time, so that when an abnormal current is detected in the first or second load, it is displayed on the display. , after a set time has elapsed, this is displayed on the display unit 50 and a control signal is transmitted to the relay output unit 60 to turn off the relay.

In addition, the status information (I) includes detection information about the load current detected by the first transformer 21 and the second transformer 22, and whether the detection information exceeds the preset pickup current and pickup time. By including excess information to display and trip information to display the trip and pickup status of the GIS DC motor controlled according to the excess information, the detection cause and operation status can be displayed on the display unit 50.

In addition, the relay output unit 60 is provided with an alarm branch unit 61 that branches the control signal and supplies it to an alarm, so that the cause of the abnormality can be notified by sound in addition to the visual information of the display unit 50. Management of Gwanjira becomes easier.

The operation of the overload trip device for a GIS DC motor according to the present invention configured as described above is as follows.

As shown in Figures 2 and 3, the overload trip device for a GIS DC motor according to the present invention is driven by supplying 125V DC power to the GIS DC motor from the power supply unit 10, and operates in an overheating state that occurs during long-term operation. To detect an overload condition, the current detection unit 20 detects the current flowing through the GIS DC motor and transmits it to the microcomputer 30 as a voltage.

The microcomputer 30 receives the normal range status through the tact switch 41 of the setting input unit 40, and determines whether the voltage transmitted from the current detection unit 20 is within the normal range.

In other words, the microcomputer 30 detects overcurrent generated due to external environmental factors such as lightning or abnormal current and operating environment such as damage to the DC motor, and when it is determined that the detected current is outside the normal range, A control signal is transmitted to the relay through the relay output unit 60 so that the power of the power supply unit 10 is tripped.

In addition, the microcomputer 30 of the present invention sets the normal range by manipulating the tact switch 41 of the setting input unit 40, and at this time, the pickup current is adjusted in the range of 1.0 to 5.0 A in increments of 0.1 A. , the pickup time is adjusted in the range of 0.1 to 10.0 Sec in increments of 0.1 Sec, and the instantaneous current is adjusted in the range of 3.0 to 20.0 A in increments of 0.5 A.

At this time, the microcomputer 30 controls the relay to be driven at a fixed time based on the pickup time. That is, if the time at which the abnormal current is detected has passed the pickup time, a control signal is transmitted through the relay output unit 60 so that the relay trips.

Meanwhile, the relay output unit 60 is provided with an alarm branch unit 61 that branches off the control signal and supplies it to an alarm, so that abnormal situations can be quickly notified through an external speaker.

In this way, the overload trip device for a GIS DC motor according to the present invention can monitor two loads, control the trip operation of the relay more accurately by finely adjusting the normal range, and display unit 50. In addition to displaying the cause of the failure to the outside, it is possible to notify the occurrence of an abnormality with a sound signal through the alarm branch 61 provided in the relay output unit 60.

The present invention is not limited to the specific preferred embodiments described above, and various modifications can be made by anyone skilled in the art without departing from the gist of the invention as claimed in the claims. Of course, such changes are within the scope of the claims.

<Explanation of symbols for main parts of the drawing>
10: power supply unit 20: current detection unit
21: first transformer 22: second transformer
30: Mycom 40: Setting input unit
41: tact switch 50: display unit
51: FND 52: LED
60: relay output unit 61: alarm branch unit

Claims (5)

A power supply unit 10 that supplies DC driving power; A first transformer 21 that detects the load current flowing in the GIS DC motor, converts the detected load current into voltage and detects the load current flowing in the first load to transmit it, and detects the load current flowing in the second load. a current detection unit 20 provided with a second current transformer 22; a microcomputer (30) that determines whether the voltage value input from the current detection unit (20) is normal and outputs a control signal and status information (I); a setting input unit 40 equipped with a tact switch 41 for inputting threshold values of pickup current, pickup time, and instantaneous current stored in the microcomputer 30; a display unit 50 provided with an FND 51 and an LED 52 indicating status information (I) transmitted from the microcomputer 30; A relay output unit 60 that drives the relay according to the control signal from the microcomputer 30 is provided,
The microcomputer 30 adjusts the pickup current in the setting input unit 40 in the range of 1.0 to 5.0 A in increments of 0.1 A, and the pickup time in the range of 0.1 to 10.0 Sec in increments of 0.1 Sec. , the instantaneous current is adjusted in the range of 3.0 to 20.0 A in increments of 0.5 A, and the relay is controlled to be driven at a fixed time,
The status information (I) displays detection information about the load current detected by the first current transformer 21 and the second current transformer 22, and whether the detection information exceeds the preset pickup current and pickup time. Includes excess information and trip information to display the trip and pickup status of the GIS DC motor controlled according to the excess information,
The relay output unit 60 is an overload trip device for a GIS DC motor, characterized in that it is provided with an alarm branch unit 61 that branches the control signal and supplies it to an alarm. delete delete delete delete

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