KR20190022123A - A ring main unit system for preventing electrical accident using temparature and pressure - Google Patents

Abstract

The present invention relates to a ring main unit (RMU) system with the temperature and pressure based accident prevention function, which comprises: an enclosure sealed and insulated by insulating gas; a switching/breaking device including an AC breaker (CB) or a load break switch (LBS) installed in the enclosure; a temperature sensor measuring the temperature of the switching/breaking device; a pressure sensor measuring the pressure of the insulating gas in the enclosure; a current sensor installed at a load end to measure a current delivered to a load; a signal process unit processing signals measured by the temperature sensor, the pressure sensor and the current sensor, and converting the signals into digital measurement values; a control unit receiving the converted measurement values and determining a risk level; an on-off relay turning on/off the switching/breaking device and a signal outputting unit outputting the risk level or the measurement values to the outside; and a display unit displaying the risk level or the measurement values to the outside. The control unit transmits a trip signal to the on-off relay according to the risk level. By such a system, a continuous overcurrent, an abnormal voltage or current can be detected even if there is no fault current, by measuring the temperature and pressure in the enclosure and predicting the risk level in the enclosure.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a ring main unit (RMU) system having temperature and pressure-

The present invention has a current sensor, a temperature sensor, and a pressure sensor in a tank enclosure of a ring main unit (RMU), calculates an accident risk by measuring current, temperature and pressure, displays the calculated accident risk To a ring main unit (RMU) system with temperature and pressure-based accident prevention functions, which automatically opens the circuit according to the degree.

In general, a ring main unit (RMU) is used for line branching, division on a wiring line for line segmentation, line branching and load protection, or an electrical system for transmitting and distributing power sent from a transmission / Monitoring, control and protection.

In particular, the ring main unit is composed of a circuit breaker, a switch, a grounding switch, and conductors in a structure sealed and insulated by insulating gas such as SF6 (sulfur hexafluoride) gas. That is, the ring main unit extinguishes the arc with the insulating gas, and the main circuit portion is mounted in the structure of the tank to maintain the insulation with the gas.

On the other hand, a load switch (LBS) and an alternating current circuit breaker (CB) are installed in the ring main unit to automatically open or close the distribution electric power, or to automatically cut off the overcurrent. That is, the switchgear or the breaker of the ring main unit can open and close the distribution electric power circuit of three-phase alternating current and shut off the circuit within a predetermined short time when the fault current such as the overcurrent or short- And protecting the load device [Patent Literatures 1 and 2].

However, the ring main unit according to the prior art cuts off the circuit only when a fault current such as an overcurrent or a short-circuit current flows on the circuit in the enclosure (or tank). Therefore, the ring main unit has a problem that the fault current does not flow, but the danger generated by the continuous overcurrent can not be detected.

Excessive voltage and current, such as continuous overcurrent in the enclosure (tank) of the ring main unit, can raise the temperature in the enclosure and increase the pressure, which can lead to a major accident in severe cases. Therefore, besides the fault current, it is necessary to monitor the continuous overcurrent, abnormal voltage and current.

[Patent Document 1] Korean Published Patent Application No. 10-2016-0084935 (published on July 15, 2016)

SUMMARY OF THE INVENTION An object of the present invention is to provide a ring main unit (RMU) having a tank enclosure having a current sensor, a temperature sensor and a pressure sensor, and measuring current, temperature and pressure (RMU) system having a temperature and pressure based accident prevention function that calculates an accident risk and displays the calculated accident risk level or automatically opens the circuit according to the calculated degree of accident risk.

It is also an object of the present invention to provide a ring main unit having temperature and pressure-based accident prevention functions for dividing the current, temperature and pressure into four stages according to the risk level, RMU) system.

It is also an object of the present invention to provide a temperature and pressure-based accident prevention function for calculating a reference temperature and analyzing the apparatus temperature by providing a temperature sensor for measuring a reference temperature and temperature sensors for a bus bar in an enclosure Ring main unit (RMU) system.

In order to accomplish the above object, the present invention relates to a ring main unit (RMU) system having a temperature and pressure-based accident prevention function, comprising: an enclosure sealed and insulated by an insulating gas; An opening / closing device including an alternating current circuit breaker (CB) or a load break switch (LBS) installed in the enclosure; A temperature sensor for measuring the temperature of the switching device; A pressure sensor for measuring the pressure of the insulating gas in the enclosure; A current sensor installed at a load end to measure a current to be distributed to the load; A signal processing unit for processing the signals measured by the temperature sensor, the pressure sensor, and the current sensor and converting the signals into digital measurement values; A controller receiving the converted measurement value and determining a risk level; An on / off relay for turning on / off the switching device; a signal output unit for outputting a risk level or a measured value to the outside; And a display unit for displaying a risk level or a measured value to the outside, and the control unit transmits a trip signal to the on-off relay according to the risk level.

The present invention also relates to a ring main unit (RMU) system having a temperature and pressure based accident prevention function, wherein the opening / closing device includes a load switch and an AC circuit breaker.

The present invention also relates to a ring main unit (RMU) system having a temperature and pressure-based accident prevention function, wherein the temperature sensor includes a measurement temperature sensor for measuring a reference temperature and a bus bar temperature of each switching / Wherein the control unit corrects the temperature measured by the temperature sensor for the bus bar by the reference temperature and determines the risk level using the corrected temperature.

The present invention also relates to a ring main unit (RMU) system having a temperature and pressure-based accident prevention function, wherein the control unit corrects the temperature measured by the following equation (1).

[Equation 1]

Stage, and T is the calibrated temperature, t is the measured temperature, t ₀ is a reference temperature, α is the correction coefficient being.

The present invention also relates to a ring main unit (RMU) system having a temperature and pressure based accident prevention function, wherein the risk level is divided into four stages of normal, attention, risk, and accident, And a trip signal is transmitted to the corresponding switching device when the level of the risk appears as a risk or an accident.

As described above, according to the ring main unit (RMU) system having the temperature and pressure-based accident prevention function according to the present invention, by measuring the temperature and pressure in the enclosure and estimating the risk level in the enclosure, The effect of being able to detect a continuous overcurrent or an abnormal voltage or current can be obtained.

Further, according to the ring main unit (RMU) system having the temperature and pressure-based accident prevention function according to the present invention, by dividing the temperature and the pressure into four stages according to the risk level, the risk level can be intuitively informed It is possible to achieve a stepwise response according to the degree of danger.

According to the ring main unit (RMU) system having the temperature and pressure-based accident prevention function according to the present invention, by correcting the currently measured temperature using the reference temperature, it is possible to reduce the influence of the temperature There is obtained an effect that a more accurate danger state can be detected.

1 is a block diagram of a configuration of a ring main unit (RMU) system having a temperature and pressure based accident prevention function according to an embodiment of the present invention;
2 is a view showing an example of a screen displaying measurement results of temperature, pressure, and current according to an embodiment of the present invention;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings.

In the description of the present invention, the same parts are denoted by the same reference numerals, and repetitive description thereof will be omitted.

First, the overall configuration of a ring main unit (RMU) system having a temperature and pressure-based accident prevention function according to an embodiment of the present invention will be described with reference to FIG.

1, a ring main unit (RMU) system having a temperature and pressure-based accident prevention function according to the present invention includes an enclosure 10 sealed and insulated by an insulating gas, an AC circuit breaker 10 installed in the enclosure 10, Closing device 11, a temperature sensor 22, a pressure sensor 23, a current sensor 21 installed at the load end, a signal processing a signal measured by the sensor, A control unit 50 for receiving a sensed value and determining a danger level, an on-off relay 40 for turning on / off the on / off device 11, and a signal output unit 61 and a display section 62.

First, the enclosure 10 is a structure such as a tank which is sealed and insulated by insulating gas such as sulfur hexafluoride (SF6). In the enclosure (10), an opening / closing device (11) and a main circuit portion thereof are provided. The sulfur hexafluoride gas extinguishes the arc in the opening / closing device 11 and maintains the insulation of the circuit portions of these devices.

The opening / closing device 11 is composed of a load break switch (LBS) or an alternating current circuit breaker (CB) which automatically opens or closes the distribution electric power or automatically cuts off the electric power by an overcurrent or the like. In the example of Fig. 1, the first LBS 11a, the first CB 11b, the second CB 11c, and the second LBS 11d are configured. The load break switch (LBS) or the alternating current circuit breaker (CB) automatically cut off the current when a fault current such as an over current or a short circuit current is supplied by using a power fuse. That is, the power fuse is interposed between the power input portion and the load switch, is electrically connected to the power input portion, and supplies current to the desired portion through the lead portion. If the current flowing in the lead portion is an overcurrent, An operation indicator provided in the power fuse is protruded and a mechanical operation part linked to the protrusion motion of the operation indicator causes the load switch to be turned into a trip state.

Next, the temperature sensor 22 is composed of a temperature sensor for measuring the reference temperature and a temperature sensor for the bus bar for measuring the bus bar temperature of each of the opening / closing devices 11. The sensor for measuring the reference temperature is a sensor for measuring the overall temperature in the enclosure 10 and is installed in a space which is separated from the bus bar of the load break switch LBS or the AC breaker CB. Also, the temperature sensor for the bus bar is a sensor for measuring the temperature of the bus bar of the opening / closing device 11 installed in the enclosure 10, and is installed in the bus bar to measure the temperature.

Preferably, the temperature sensor 22 measures the bus bar temperature inside the enclosure 10 by using one sensor for reference temperature measurement and six temperature sensors for three-phase two-circuit bus bar (BUS BAR).

On the other hand, when calculating the risk level in steps for the temperature, do not directly use the measured busbar temperature but use it after using the reference temperature (or ambient temperature, environmental temperature). This is to evaluate the risk by normalizing the current measurement temperature to ambient temperature, since the ambient temperature may vary widely depending on the season or surrounding environment.

Next, the pressure sensor 23 is installed in the enclosure 10 between the inside and the outside of the enclosure tank, and measures the pressure of the hexafluoride termination SF6 which is put into the enclosure 10. The higher the pressure, the higher the risk.

Next, the current sensor 21 is a conventional CT (Current Transformer) sensor, which is connected to a load to measure current. That is, the current sensor 21 is provided at the load end to measure the current supplied to the load. In particular, an OCR (overcurrent relay) is installed at the output of the AC breaker (CB).

Next, the signal processing unit 30 processes signals received from the current sensor 21, the temperature sensor 22, and the pressure sensor 23, and outputs digital values such as a current value, a temperature value, and a pressure value.

The signal processing unit 30 receives the sensor signal, removes noise, amplifies the digital signal, and outputs the digital signal. The signal processing section 30 is constituted by a signal amplifier 31, a noise filter 32 and an analog digital (AD) converter 33.

Since the sensor signals output by the respective sensors are all electrical signals at a fine level, appropriate post-processing is required to process them. First, the signal amplifier 31 amplifies the sensor signal. In addition, the sensor signal must be appropriately amplified in order to post-process the sensor signal, which is a fine level electric signal, into a digital signal and to derive the information required by the control unit.

The AD converter 33 converts the sensor signal into a digital signal. Since the sensor signal is an analog signal, it is advantageous that the controller 50 converts the sensor signal into a digital signal in order to determine the risk of the ring main unit based on the sensor signal.

The noise filter 32 is a filter for reducing noise in a digital signal. In particular, the noise filter 32 can compensate the linearity of the digital signal by reducing the level of the noise of the harmonic component in the digital signal.

Further, the noise filter 32 can correct the digital signal according to the reference temperature. That is, since each sensor changes its measurement value under the influence of the internal temperature, accurate measurement can be performed by correcting the error caused by the temperature depending on the internal temperature of the enclosure 10.

Next, the control unit 50 determines a danger level in response to the digital signal output from the signal processing unit 30, that is, the temperature, pressure, and current value, and outputs a risk level or an alarm signal according to the determination result .

First, the control unit 50 calculates the corrected temperature with respect to the received temperature value (digital value). The corrected temperature is the temperature that reflects the reference temperature to the measured temperature value. Specifically, the measured temperature value is corrected according to the following formula.

[Equation 1]

Here, T is the calibrated temperature, t is the measured temperature, t ₀ is a reference temperature. And? Is a correction coefficient and has a value less than 0.4. That is, the correction coefficient indicates the reflection ratio of the reference temperature and is a value determined in advance.

Further, the control unit 50 determines the risk level according to the magnitude of the corrected temperature. Preferably, the risk level is divided into four levels: normal, attention, risk, and accident.

In addition, the control unit 50 determines a risk level for the received pressure value. Preferably, the level of risk to pressure is divided into four levels, such as normal, caution, risk, and accident, such as temperature risk level.

In addition, the control unit 50 also determines the level of risk for the magnitude of the current. The risk level for the current is also divided into four steps, such as the temperature or pressure described above.

In addition, the control unit 50 determines an operation to be performed according to each level in advance, and performs a corresponding operation according to the determination result of the level of risk. Preferably, the control unit 50 transmits a trip signal to all or a part of the opening / closing device 11, if the risk level is determined to be a danger or an accident stage. All or part of the opening / closing device 11 is opened by the trip signal of the control unit 50. [

The control unit 50 outputs the contents of the result to the signal output unit 61 or the display unit 62 according to the risk level.

The on / off relay 40 is a relay which turns on / off the device 11, and when the trip signal is generated by the temperature value and the pressure value, the on / off device 40 Is opened.

Also, the on-off relay 40 can be directly turned on / off by the circuit of the AC breaker CB.

The signal output unit 61 transmits a danger level or an alarm signal output from the control unit 50 to a system (Scada system or the like) that collectively controls or controls the power system. Preferably, the signal output unit 61 transmits to the outside through a serial communication method such as RS485. The manager terminal or the like can receive data transmitted from the signal output unit 61 and monitor the ring main unit remotely.

The display unit 62 displays a danger level or an alarm signal output from the control unit 50 on a display device such as a display, and displays the risk level or the alarm signal so that the user or the administrator can visually confirm it in real time.

An example of a screen displayed on the display unit is shown in Fig.

As shown in FIG. 2, temperature, current, pressure, and the like are displayed in the form of a gauge, and the risk level according to each data value is displayed on the screen. By displaying the level of risk in stages, it is intuitively provided to know the current state even if there is not much knowledge about the opening / closing device of the ring main unit.

The invention made by the present inventors has been described concretely with reference to the embodiments. However, it is needless to say that the present invention is not limited to the embodiments, and that various changes can be made without departing from the gist of the present invention.

10: enclosure 11: opening / closing device
21: current sensor 22: temperature sensor
23: Pressure sensor
30: Signal processing section 31: Signal amplifier
32: noise filter 33: AD converter
40: On-off relay 50:
61: Signal output section 62: Display section

Claims (5)

In a ring main unit (RMU) system having temperature and pressure based accident prevention functions,
An enclosure sealed and insulated by insulating gas;
An opening / closing device including an alternating current circuit breaker (CB) or a load break switch (LBS) installed in the enclosure;
A temperature sensor for measuring the temperature of the switching device;
A pressure sensor for measuring the pressure of the insulating gas in the enclosure;
A current sensor installed at a load end to measure a current to be distributed to the load;
A signal processing unit for processing the signals measured by the temperature sensor, the pressure sensor, and the current sensor and converting the signals into digital measurement values;
A controller receiving the converted measurement value and determining a risk level;
An on-off relay for turning on / off the switching device,
A signal output unit for outputting a risk level or a measured value to the outside; And
A display unit for displaying a risk level or a measured value to the outside,
And the control unit transmits a trip signal to the on-off relay according to the level of the risk.
The method according to claim 1,
(RMU) system having a temperature and pressure based accident prevention function, characterized in that the opening / closing device includes a load switch and an AC circuit breaker.
The method according to claim 1,
Wherein the temperature sensor comprises a temperature sensor for measurement for measuring a reference temperature and a temperature sensor for a bus bar for measuring a bus bar temperature of each switching device,
Wherein the control unit determines a risk level by using the corrected temperature by correcting the temperature measured by the bus bar temperature sensor based on the reference temperature and a ring main unit RMU ) system.
The method of claim 3,
Wherein the control unit corrects the temperature measured by the following equation (1): < EMI ID = 1.0 >
[Equation 1]

Stage, and T is the calibrated temperature, t is the measured temperature, t ₀ is a reference temperature, α is the correction coefficient being.
The method according to claim 1,
The risk level is divided into four stages: normal, attention, risk, and accident,
Wherein the control unit transmits a trip signal to the corresponding on / off device when the risk level is indicated as a danger or an accident. The ring main unit (RMU) system has a temperature and pressure based accident prevention function.

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