KR100441947B1 - unit checking error of current transformer and unbalance of 3 phase by processor - Google Patents

Abstract

The present invention is an instrument current transformer 10 for receiving a three-phase AC AC power supply, and an analog circuit 20 for converting an AC input current value input from the instrument current transformer 10 into a voltage value. ), A processor unit 30 for calculating an alarm occurrence by determining whether there is an abnormality by calculating three phase data values received from the analog circuit 20, and an abnormality occurrence and line unbalance through the analog circuit 20. From the configuration in which the alarm device 40 which displays the abnormality even at the time of connection, the sudden load increase or decrease due to the increase in the late-night load and the substation unmanned by the person always checks whether or not the phase unbalance occurred to improve whether three-phase unbalance occurred Automatically detect and take precautions before line breakdown to prevent power outages, maximizing work efficiency and power supply quality Enhance and relates to an instrument current transformer and the three-phase unbalanced failure detecting apparatus it can be accurately determined whether an error occurs in the current transformer for instruments has the effect that can prevent a power outage caused by a malfunction of the protection relay.

Description

Instrument checking and three-phase unbalanced fault detection device {unit checking error of current transformer and unbalance of 3 phase by processor}

The present invention relates to an instrument current transformer and a three-phase unbalance abnormality detection device, and more particularly, when a three-phase current unbalance occurs, a phase current unbalance is determined by a person to determine a three-phase unbalance state, and a phase load unbalance is solved. The present invention relates to an instrument current transformer and a three-phase unbalance abnormality detection device for determining whether an instrument current transformer (CT) circuit is open or abnormal.

In general, the current transformer used in current instrument detects 22.9 [kV] power line three-phase current and checks the phase current using a current switching switch to determine whether it is three-phase unbalanced. If the above occurs, if the correction value is exceeded in the protection relay has a problem that the line must be blocked by the breaker.

The present invention is to solve such a conventional problem, its purpose is to measure the phase current when the three-phase current unbalance occurs, and to determine the three-phase unbalance state to solve the phase load unbalance for the problem and instrument This is to determine whether the CT circuit is open or abnormal.

1 is an overall block diagram of an instrument current transformer and a three-phase unbalance abnormal detection device according to an embodiment of the present invention.

2 is a control flowchart of the processor unit of the instrument current transformer and the three-phase unbalance detection device according to an embodiment of the present invention.

Code descriptions for the main parts of the drawings

10: current transformer 20 for instruments; analog circuit

21; primary amplifier 22; rectifier

23; voltage drop 24; secondary amplifier

25; overvoltage protection unit 26; filter unit

30; processor unit 40; alarm device

DETAILED DESCRIPTION Hereinafter, the most preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention. . Other objects, features, and operational advantages, including the purpose, working effects, and the like of the present invention will become more apparent from the description of the preferred embodiment.

For reference, the embodiments disclosed herein are only presented by selecting the most preferred examples to help those skilled in the art from the various possible examples, the technical spirit of the present invention is not necessarily limited or limited only by this embodiment, Various changes and modifications are possible within the scope without departing from the technical spirit of the present invention, as well as other equivalent embodiments will be found.

1 is an overall block diagram of an instrument current transformer and a three-phase unbalance abnormality detection device according to an embodiment of the present invention, and FIG. 2 is a control flowchart of a processor unit according to an embodiment of the present invention.

The present invention relates to a device for monitoring the abnormal state of the current transformer of the instrument and to monitor the unbalance of the three-phase current, as shown in Figure 1 or 2, for the instrument to be applied to the three-phase AC AC power supply Current transformer 10, an analog circuit 20 for reading the AC input current value input from the instrument current transformer 10 and converting it into a voltage value, and a three-phase data value received from the analog circuit 20 The processor unit 30 for determining whether there is an abnormal occurrence by generating a warning signal and generating an alarm signal, and the alarm device 40 for displaying an abnormality in case of abnormal occurrence and unbalance of the line through the analog circuit 20 are connected. Have

The analog circuit 20 converts and outputs the primary amplifier 21 to amplify the signal output from the instrument current transformer 10 and the power output from the primary amplifier 21 to DC power. The rectifying unit 22, the voltage drop unit 23 for stepping down the DC voltage output from the rectifying unit 22, and the secondary amplifier 24 for amplifying and outputting the power output from the voltage drop unit 23. And an overvoltage protection unit 25 for blocking an overvoltage of the voltage output from the secondary amplifier 24, and a filter unit 26 for removing high frequency components output from the process pressure protection unit. Has a configuration to be connected.

The processor unit 30 outputs an alarm when an abnormality occurs by determining whether there is an abnormality of the instrument current transformer 10 through the three-phase power supply after initializing, and subtracts the maximum and minimum values selected from the three phases in the normal state. If the sum is more than a certain value, the counter is initialized to "0" as a normal signal, but if it is less than 1, the counter is increased as an abnormal state. It has a configuration.

Referring to the effect of the instrument current transformer and the three-phase unbalance error detection device according to an embodiment of the present invention configured as described in detail as follows.

The present invention relates to a device for monitoring the abnormal state of the current transformer of the instrument and to monitor the unbalance of the three-phase current, as shown in Figure 1 or 2, the analog circuit 20 is applied to the three-phase AC AC power supply In the existing 22.9 [kV] power line, the instrument current transformer (10) (CT) is input to the secondary side in a ring-type 2500: 1 ratio to acquire necessary data without damaging the circuit. At this time, since the maximum output current of the ring-type instrument current transformer 10 of the 2500: 1 ratio is 2 [mA], the maximum voltage is 0.2 [V]. Since the processor unit 30 has a small value to be recognized as data, there is a risk of malfunction and the analog circuit 20 has a voltage drop of up to 1 [V] when rectifying with a DC power supply. The output power is amplified by the primary and secondary amplifiers 21 and 24 in the analog circuit 20.

The amplified AC power is converted into a DC voltage through the rectifying unit 22 in the analog circuit 20, and the voltage is lowered to 1/2 through the voltage drop unit 23 so that the output voltage of the processor unit 30 is reduced. In order to stabilize the voltage recognition, the second amplifier 24 is transferred to the overvoltage protection unit 25.

The voltage passing through the overvoltage protection unit 25 is finally transmitted to the processor unit 30 while the high frequency component is removed through the filter unit 26.

The processor unit 30 calculates a voltage value input through the analog circuit 20 and generates an alarm when the result value is at least 0.3. At this time, the calculated value is calculated by selecting the maximum value and the minimum value as the maximum value among the three phases and the smallest value among the rest as the minimum value.

In addition, the processor unit 30, if there is no more than one input of the three-phase input stage can be seen as disconnection or opening of the circuit of the instrument current transformer 10 will generate an alarm, in the case of the absence of all three-phase input It is judged as a power failure state or a cease-fire state and becomes qualitative state so that an alarm does not occur.

On the other hand, since the processor unit 30 is operated at 20 [MHz], if a 1-click command is executed, the execution time is 1 / 20,000,000 seconds (0.5 ms). There is a risk of violation.

Since the actual three-phase unbalance is not sudden, there is no big problem even if the operation is performed once every 10th of a second, so the processor unit 30 calculates the intermittent signal every 10 (ms) using the time set in the internal program. Do it.

When determining whether there is an abnormality in the instrument current transformer 10, if there is always an input value and there is no input of the remaining phase, it is determined that the current transformer 10 is abnormal. If the input value of all three phases is "0", the breaker is turned off. In this case, it is determined as normal state.

The expression is as follows.

The formula is Alarm signal is generated and when the result data is less than 3, it is initialized to "0" as a normal signal.

The processor unit 30 generates an alarm only when the abnormal signal is continuous for 10 seconds or more in order to prevent a malfunction. Since the processor unit 30 performs the operation once every 1/10 second, the counter is incremented when an abnormal signal is generated. When the normal signal is generated, the processor unit 30 makes the counter '0' and increments the counter again from the next operation. If the counter reaches 1000, an alarm is generated by judging that an abnormal signal has occurred continuously for 10 seconds.

The present invention, which acts in this way, improves that a person always checks to know whether phase imbalance occurs when sudden load increase or decrease due to increased late-night load and substation unmannedness automatically detects the occurrence of three-phase unbalance and before the line failure occurs. It is possible to prevent the power failure by taking measures to maximize the efficiency of the work, improve the power supply quality, and accurately determine the abnormality of the current transformer for the instrument, thereby preventing the power failure caused by the malfunction of the protection relay.

Claims (3)

(delete) (delete) (Correction) An analog current transformer (10) for receiving a three-phase AC AC power supply, and an analog circuit 20 for converting the AC input current value input from the instrument current transformer (10) into a voltage value (20). ), A processor unit 30 for calculating an alarm occurrence by determining whether there is an abnormality by calculating three phase data values received from the analog circuit 20, and an abnormality occurrence and line unbalance through the analog circuit 20. Alarm device 40 for displaying abnormalities even when the connection is made, The analog circuit 20 converts the primary amplifier 21 to amplify the signal output from the instrument current transformer 10 and the power output from the primary amplifier 21 to DC power for output. The rectifier 22, a voltage drop section 23 for stepping down the DC voltage output from the rectifier section 22, and a secondary amplification section 24 for amplifying and outputting the power output from the voltage drop section 23. ), An overvoltage protection unit 25 for blocking an overvoltage of the voltage output from the secondary amplifier 24, and a filter unit 26 for removing high frequency components output from the process pressure protection unit. ) Are connected, The processor unit 30 outputs an alarm when an abnormality occurs by determining whether there is an abnormality of the instrument current transformer 10 through the three-phase power supply after initializing, and subtracts the maximum and minimum values selected from the three phases in the normal state. If the sum is more than a certain value, the counter is initialized to "0" as a normal signal, but if it is less than 1, the counter is increased to an abnormal state. Instrument current transformer and three-phase unbalance abnormality detection device characterized in that the connection is made so that.