KR101070822B1 - A abnormality detector of distributing board with self-diagnostic capabilities - Google Patents

Abstract

The present invention relates to an abnormality detection device of the switchgear, the abnormality detection device according to the present invention is an ultraviolet sensor for detecting the ultraviolet rays generated by the discharge in the switchgear, and the shaping to convert the arc signal output from the ultraviolet sensor into a logic signal A circuit, an arc counter for counting the number of arc occurrences by counting pulses of the shaped arc signal, a pulse width converter for calculating a pulse duration of the shaped arc signal, an R phase, an S phase of the live switchboard live, Tracking detection unit having a plurality of current sensors for measuring the current in the T phase, and the voltage of the pulse transformer of the ultraviolet sensor periodically checks the ultraviolet region detection accuracy of the ultraviolet sensor when the pulse transformer voltage falls below the minimum discharge start voltage Diagnoses that the signal is reduced and inputs the signal to the current sensor. When the voltage level is periodically monitored and maintained below a reference value for a predetermined time, the self-diagnostic unit for diagnosing an abnormality in the current sensor and the arc detector and the tracking detector detect an arc signal and a tracking signal, and detect the same. And a digital signal processor for diagnosing the occurrence of arcing and tracking, generating an alarm according to the diagnosis result, and transmitting the generated signal to a remote monitoring apparatus.

Description

A Abnormality Detector of Distributing Board with Self-Diagnostic Capabilities

The present invention relates to an apparatus for detecting abnormality of a switchgear which detects arc and tracking occurrence using a UV sensor and a current sensor to monitor the state of the switchgear in real time, and self-diagnoses the performance of the UV sensor and the current sensor.

In the switchgear, power failures and electrical accidents occur without notice due to internal parts failure and insulation deterioration, which increases not only economic loss but also impact on production disruption and society due to power failure. And reliability are very important issues.

Despite the diversified efforts to prevent electrical fires, 102,560 electrical fires out of the total number of fires (295,497) occurred in the last 10 years due to the increase in various loads, including buildings and large water users. It is 34.7% and the average increase rate is 5.7%.

 Electric fires are on the rise with the increase in the use of electric devices and electrical equipment. As a result, electric fires are damaging to people's lives and property as well as to the national economy. There is a great need for this. In particular, high-voltage / low-voltage switchboards and switchboards of large consumers with high buildings and power usage are urgently required to develop devices and monitoring systems for early detection and detection of electric fires.

In order to cope with electric fire accidents, various protection devices including circuit breakers, which are currently installed, have a function to cut off the circuit when an overcurrent occurs in the load circuit, but overheating, disconnection, short circuit due to poor contact in the power distribution system The tracking phenomenon caused by the arc generation and the insulation coating deterioration by the wiring breaker cannot solve the accident.

In the case of an arc fire, abnormal current flows due to ground fault, overcapacity, contact with other objects, etc., so that the busbars, cables, wire-to-wire contacts, and terminal contacts inside the high-voltage / low-voltage switchboard are overheated, which causes contact with other objects. As a result, the wire is cut off at the fault and it is interrupted or generates a continuous repetitive arc with partial contact.

Due to environmental pollution such as dust, soot and moisture around the switchgear, the insulation layer between the conductors is carbonized by micro discharge through the wire covering material in contact with the terminal block. The leakage current gradually increases along this carbonization conductor, and finally, the electric wire covering material ignites with the tracking breakdown between the conductors, thereby generating an electric fire in the distribution board. As described above, more than half of electric fires cause electric fires and casualties by arcing and tracking.

In the conventional arc and tracking detection method, the presence or absence of an arc was determined by digitizing and frequency analyzing a current waveform obtained by a current transformer of each phase. In this method, the detection probability is high when the current in the feeder of the switchgear is a resistive component, but in the case of the capacitive by L and C and the load of the inductive component, it is impossible to accurately detect the arc waveform.

An electric arc refers to a symptom that occurs when an electrical short occurs due to a poor contact of an electric wire or a poor coating between lines. An arc can cause personal injury and property loss due to fire damage, etc. Predictive judgment is emerging as an important issue.

Conventional arc breakers used in the United States and North America are mainly Arc Fault Current Interrupter (AFCI) to detect arcs in low voltage lines in homes. Arc arcs are caused by short circuits in outlets, wire breaks, and poor contact. Shut off the current. As such, a detection apparatus for arc and tracking signals generated by poor contact, short circuit, and deterioration of a high voltage / low voltage line of a switchgear has not been applied until now.

The present invention has been made to solve the above problems, the arc and tracking signals are detected by using an ultraviolet sensor and a current sensor, and the detected signals are detected by fast Fourier transform and stochastic statistical analysis to detect the arc and tracking. An object of the present invention is to provide an abnormality detection device for a switchgear.

In addition, the present invention is to provide an abnormality detection device of the switchgear for periodically testing the performance of the ultraviolet sensor and the current sensor.

In addition, the present invention is to provide an apparatus for detecting abnormality of the switchgear for diagnosing the occurrence of abnormalities such as arc and tracking by monitoring the state of the switchgear in real time.

The abnormality detection device of the switchgear of the present invention for achieving the above object is an ultraviolet sensor for detecting the ultraviolet rays generated by the discharge in the switchgear, a shaping circuit for converting the arc signal output from the ultraviolet sensor into a logic signal, An arc counter for counting the number of arc occurrences by counting pulses of the shaped arc signal, a pulse width converter for calculating a pulse duration of the shaped arc signal, and currents of R, S, and T phases of the live switchboard Tracking detection unit having a plurality of current sensors for measuring each of the and the voltage of the pulse transformer of the ultraviolet sensor periodically checks that the pulse transformer voltage falls below the minimum discharge start voltage, the ultraviolet region detection accuracy of the ultraviolet sensor is reduced Is diagnosed, and the voltage level of the signal input to the current sensor And periodically detect the arc signal and the tracking signal through the self-diagnostic unit for diagnosing an abnormality in the current sensor and the arc detection unit and the tracking detection unit. And a digital signal processor for diagnosing the occurrence of arcing and tracking, generating an alarm according to the diagnosis result, and transmitting the alarm to the remote monitoring apparatus.

The ultraviolet sensor may include a waveform generator configured as an operational amplifier to generate a triangular waveform, and a pulse transformer driven by the generated triangular waveform to generate a direct current high voltage to supply the ultraviolet sensor.

The arc counter may output an arc generation signal when the number of arc generations is equal to or greater than a threshold value.

The digital signal processor may perform a fast Fourier transform operation on the arc signal to calculate detection elements such as a high frequency component, a peak value, and an effective value of the arc signal.

The digital signal processor may perform fast Fourier transform operation on the tracking signal to calculate detection elements such as an effective value, a current slope, a short circuit current, a current peak value, and an average value of the tracking signal.

In addition, the abnormality detection apparatus of the switchgear according to the present invention further includes an alarm means for outputting an alarm under the control of the digital signal processing unit.

As described above, the apparatus for detecting abnormality of the switchgear according to the present invention detects arc and tracking signals using an ultraviolet sensor and a current sensor, and detects the detected signals through high-speed Fourier transform and probabilistic statistical analysis. Arcs and tracking occurring at low pressure contacts can be detected.

In addition, the present invention monitors and diagnoses the status of the switchgear in real time by monitoring the abnormal signs related to the arc and tracking occurrence of the switchgear can prevent accidents and property damage due to the expansion of the electric fire.

1 is an example showing the configuration of a switchgear according to the present invention.
2 is a block diagram showing an abnormality detection device of a switchgear according to an embodiment of the present invention.
FIG. 3 is a diagram illustrating a structure of an ultraviolet sensor included in the abnormality detecting apparatus of the switchboard of FIG. 2.
4 is a circuit diagram illustrating a high voltage generation circuit of the ultraviolet sensor of FIG. 3.
5 is an exemplary diagram illustrating an output waveform of the ultraviolet sensor of FIG. 3.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The present invention relates to a cable head, a metering out fit (MOF) connection, a power fuse (PF) connection, a vacuum circuit breaker (VCB) terminal block, and a high voltage bus connection. Abnormal signals such as arc signals and tracking signals generated from high voltage parts such as low voltage parts such as busbar connections of transformers, low voltage side busbars, air circuit breakers, primary and secondary terminal blocks and connectors, distribution panel terminal blocks and connectors, etc. The present invention relates to a method for detecting and monitoring and diagnosing the status of switchboards.

1 is an example showing the configuration of a switchgear according to the present invention.

Referring to Figure 1, the inner space of the main body 1 of the switchgear is separated up and down by the support (2). Air circuit breakers (ACB) 10, automatic indoor section switches (ISS) 20, power fuses (PF) 30, lightning arresters on the upper side of the support (2) (Lightning Arrester: LA) 40 is disposed. In addition, a lower side of the support 2 is provided with a transformer (TR) 50 and a metering out fit (MOF) 60 on one side of the transformer 50.

The switchgear is a high voltage input through the high-voltage line is introduced into the power fuse 30 and the arrester 40 through the failure section automatic switchgear 20, the transformer transformer current transformer in the high pressure line through the power fuse 30 ( 60) is installed so that the voltage and current can be read for measuring the amount of power used. The voltage and current values detected by the transformer transformer current transformer 60 are connected to the voltmeter and the ammeter and the low voltage shown on the secondary low voltage terminal of the transformer 50 is connected to the load via an air circuit breaker 10 connected by a cable. To be applied to

In addition, an arc sensor and a tracking sensor are installed in the high voltage busbar contact portion, the transformer secondary side busbar contact portion, and the cable connection portion in the switchboard (see the asterisk in FIG. 1).

In addition, an integrated monitoring controller 70 for monitoring the operation of the switchgear is installed outside the body 1 of the switchgear. The integrated monitoring controller 70 includes an abnormality detection device 100 for diagnosing abnormality of the switchgear through the arc sensor 111 and the tracking sensor 121.

FIG. 2 is a block diagram illustrating an abnormality detecting apparatus of a switchgear according to an embodiment of the present invention, and FIG. 3 is a diagram illustrating a structure of an ultraviolet sensor included in the abnormality detecting apparatus of the switchgear of FIG. 2. 3 is a circuit diagram illustrating a high voltage generation circuit of the ultraviolet sensor of FIG. 3, and FIG. 5 is an exemplary diagram illustrating an output waveform of the ultraviolet sensor of FIG. 3.

As shown in FIG. 2, the abnormality detection apparatus 100 of the switchboard according to the present invention includes an arc detector 110 and a tracking detector 120 for detecting the occurrence of arc and tracking.

The arc detector 110 includes the arc sensor 111 for detecting an arc signal. The arc sensor 111 is a non-contact UV sensor, which uses the principle of the photoelectric effect of metal and gas. The arc sensor 111 used in the present invention does not require a filter and has a high detection accuracy unlike a conventional semiconductor type ultraviolet sensor.

The ultraviolet sensor detects ultraviolet rays generated by discharge or the like in the switchgear, and converts the generated ultraviolet rays into voltage signals (waveforms) and outputs them.

Such an ultraviolet sensor is composed of an anode electrode 201 and a cathode electrode 202 which are disposed in the UV glass bulb 200 as shown in FIG. 3. The anode electrode 201 is formed of a metal wire forming an oval loop and is spaced apart from the cathode electrode 202 formed of a metal plate at a predetermined interval. Leads 201a and 202a respectively formed on one side of the anode electrode 201 and the cathode electrode 202 are exposed to the outside through the bottom sealing part of the ultraviolet transmission glass tube 200 to form an external terminal of the ultraviolet sensor. do. DC power is applied to the two leads 201a and 202a at a constant voltage.

When the ultraviolet light transmitted through the glass tube touches the cathode electrode 202 while the anode potential is applied to the anode electrode 201, electrons are excited at the cathode electrode 202 by photon energy. The excited electrons are attracted to the anode electrode 201 side by the anode potential so that a current flows between both electrodes.

In addition, the ultraviolet sensor used as the arc sensor 111 may quickly detect the ultraviolet component of the far arc and may detect a micro discharge such as a high pressure corona discharge. In addition, as shown in Table 1, the arc sensor 111 has an ultraviolet sensitivity of 185nm ~ 260nm and despite the small size can detect the abnormal phenomenon within 5m at a 120 ° angle of detection range of ultraviolet radiation quickly. have.

parameter range unit Spectral response 185-260 Nm Window material UV glass - Detection range 120, 5 °, m Discharge start voltage (including UV radiation) 280 Vdc Max

The arc sensor 111 includes a high voltage generating circuit for applying a DC high voltage power. As shown in FIG. 4, the high voltage generation circuit includes a waveform generator including an operational amplifier (for example, TL082) and a pulse transformer for generating a DC high voltage. The waveform generator generates a triangular waveform having a period of about 50 ms, and the generated triangular waveform drives the pulse transformer through the transistor Q4. The pulse transformer generates a DC high voltage of about 300V and is rectified by the diode D4 and the capacitor C21 to be supplied to the anode electrode of the discharge tube.

The arc detector 110 includes an analog filter 112 that receives an arc signal output from an arc sensor 111 that detects ultraviolet rays generated from a discharge tube, and removes a noise signal from the received arc signal. The analog filter 112 removes and outputs noise of an output waveform output from the ultraviolet sensor through analog low pass filtering (see FIG. 5).

The arc detector 110 includes a shaping circuit 113 for shaping a signal output from the analog filter 112, an arc signal counter 114, a pulse width converter 115, and a data latch 116. .

The shaping circuit 113 converts the arc signal filtered by the analog filter 112 into a logic signal. Various types of well-known shaping circuits (eg, limiters, clamping, etc.) may be used in the present invention. The shaping circuit 113 transmits the shaped arc signal to the arc signal counter 114 and the pulse width converter 115. Here, shaping the output waveform output from the ultraviolet sensor through analog filtering is for facilitating detection of minute arc or tracking.

The arc signal counter 114 counts the number of arc generation times by counting pulses of the standardized arc signal. The arc signal counter 114 recognizes that an arc has occurred when the number of arc occurrences is greater than or equal to a threshold and outputs an arc generation signal to the data latch 116.

The data latch 116 stores data output from the arc signal counter 114 and the pulse width converter 115. According to the data stored in the data latch 116 to control the relay (relay) of the alarm means 150 to be described later to generate an alarm or stop the alarm.

The pulse width converter 116 is a circuit for calculating the pulse duration of the arc signal. The pulse width converter 116 generates an arc start signal in a 'high' state and transmits the arc start signal to the digital signal processor 130 to be described later to indicate arc generation. .

Meanwhile, the pulse width converter 116 generates an arc stop signal in a 'low' state and outputs the arc stop signal to the digital signal processor 130 to indicate that the arc stop state. Therefore, the digital signal processor 130 stops the arc alarm output when the arc stop signal is input.

The tracking detector 120 includes a tracking sensor 121 and a buffer 122. The tracking sensor 121 is a current sensor (CT) that measures a tracking current generated on the live line of the switchgear, and detects a tracking signal that is a micro discharge phenomenon of a low voltage line. The tracking sensor 121 is composed of current sensors 121a, 121b, and 121c for measuring currents of R, S, and T phases, respectively.

The current waveforms transmitted from the current sensors 121a, 121b and 121c are input to an analog / digital converter (not shown) of the digital signal processor 130 through the buffer 122. The buffer 122 delays the input of the current waveform in accordance with the processing speed of the analog / digital converter.

The arc sensor 111 and the tracking sensor 121 are installed in a high voltage busbar contact part, a transformer secondary side bus bar contact part, a cable connection part, and the like in the power distribution panel shown in FIG. 1.

The abnormality detection apparatus 100 includes the digital signal processor 130 for signal processing the arc signal and the tracking signal detected by the arc detector 110 and the tracking detector 120.

The digital signal processor 130 receives a signal and data output from the arc detector 110 and the tracking detector 120 as an input and performs a Fast Fourier Transform (FFT) operation and statistical analysis. To accurately detect the occurrence of arcing and tracking.

In addition, the digital signal processor 130 may detect a high frequency component, an effective value, a peak value, or the like for an output waveform (arc signal) output from the arc sensor 111 of the arc detector 110 through an FFT operation. Calculate.

In addition, the digital signal processor 130 calculates detection elements such as an effective value, a current slope, a short circuit current, a current peak value, and an average value of the current waveform measured by the current sensor of the tracking detector 120 through an FFT operation. do.

The digital signal processor 130 analyzes signals detected by the arc detector 110 and the tracking detector 120 based on the calculated detection element to diagnose whether or not an arc and tracking are generated and the like. . Here, the digital signal processor 130 analyzes signals detected by the arc detector 110 and the tracking detector 120 to build and verify a database through a detection algorithm to determine whether or not arc and tracking are generated. Can be. Such analytical data is transmitted to a remote monitoring device (not shown) to obtain information on risk factors and to prevent large accidents in advance. The remote monitoring apparatus may be implemented as a server, a personal computer, a human machine interface (HMI), or the like.

The abnormality detection device 100 includes a communication unit 140 including a serial communication unit 141 such as RS-485 and an optical communication unit 142.

The serial communication unit 141 converts the sensor information and the respective data obtained by the digital signal processing unit 130 according to the communication control signal of the digital signal processing unit 130 into MOD-BUS standard data to monitor the remote monitoring device. To pass. Data transmitted to the remote monitoring device is processed for each information or use to determine the shape of the arc.

The optical communication unit 142 is used to improve the malfunction due to noise because a strong electromagnetic field is formed by a transformer and a plurality of heavy electric machines installed in the switchgear can cause a serious malfunction in the transmission and communication of the sensor output signal.

The optical communication unit 142 arranges the information and the data of the sensor acquired by the digital signal processing unit 130 into MOD-BUS standard data and transmits the data to the remote monitoring apparatus through the optical communication line. The optical communication unit 142 includes a logic signal converter that converts logic information of the digital signal processor 130 into a pseudo emitter couple logic (PECL) signal. In addition, the optical communication unit 142 includes an optical signal converter (optical transceiver) for converting the PECL signal into optical information and outputting the optical cable line. The optical signal converter converts the received optical cable information into a PECL signal, and the converted PECL signal is converted into a logic signal by a logic signal converter and input to the digital signal processor 130.

The optical communication unit 142 enables optical communication between the abnormality detection device 100 and the remote monitoring device, and the data transmitted to the remote monitoring device are processed for each information or use to determine the shape of the arc. Used.

The abnormality detection device 100 is provided with an alarm means 150 for generating or stopping an alarm alarm when the relay is driven according to the data stored in the data latch 116.

The abnormality detection apparatus 100 is provided with a display unit 160 for processing the data calculated by the digital signal processor 130 to display the result value and information related to the arc.

The abnormality detecting apparatus 100 includes a power supply unit 170 for supplying power to the abnormality detecting apparatus 100. The power supply unit 170 is implemented as a DC / DC converter for converting the DC power input from the inside or outside to a DC power of a different voltage.

The self-diagnostic part 180 which performs self-diagnosis of the arc sensor 111 and the tracking sensor 121 is provided. The self-diagnosis unit 180 periodically checks a voltage of a pulse transformer which is a part of the arc sensor 111 and checks whether the voltage falls below a minimum discharge start voltage. As a result of the check, when the voltage of the pulse transformer falls below a minimum discharge start voltage, the self-diagnosis unit 180 diagnoses that the accuracy of ultraviolet region detection for the arc sensor 111 is reduced.

The self-diagnostic unit 180 monitors the voltage level of the input signal input to the tracking sensor 121 at intervals of 10 seconds, and when the voltage level is maintained for less than a reference value (lowest value) for 1 second, the tracking sensor 121. We diagnose that there is abnormality in.

The self-diagnostic unit 170 transmits a diagnosis result to the digital signal processor 130, and the digital signal processor 130 transmits the received diagnosis result to the display unit 170 through a serial communication unit 141. The diagnosis result is displayed on the display unit 170.

Hereinafter, the operation of the abnormality detection apparatus of the switchgear according to the present invention will be described in detail.

The digital signal processor 130 of the abnormality detection apparatus 100 of the switchboard according to the present invention detects the arc signal and the tracking signal through the arc detector 110 and the tracking detector 120. The arc detector 110 detects ultraviolet rays generated in the switchboard through the arc sensor 111, converts the detected intensity of the ultraviolet rays into a voltage signal, and analog-filters the converted voltage signal. In addition, the arc detection unit 110 shapes the peeled voltage signal through the shaping circuit 113, and counts the number of arc generation times by counting pulses of the shaped voltage signal through the arc counter 114. In addition, the arc detector 110 calculates a pulse duration (arc duration) of the standardized voltage signal using the pulse width converter 116.

When the arc signal and the tracking signal are detected, the digital signal processor 130 calculates a detection element through an FFT operation on the detected arc signal and the tracking signal. The detection element includes an effective value of the arc signal, a high frequency component, a peak value, and the like, and includes an effective value of the tracking signal, a current slope, a short circuit current, a peak value, an average value, and the like.

The digital signal processor 130 analyzes the calculated detection elements to diagnose whether arcing and tracking occur, and transmits the information detected by the ultraviolet sensor and the current sensor and the calculated detection elements to a remote monitoring apparatus. Here, the digital signal processor 130 diagnoses that an arc has occurred when the number of arc occurrences occurs 5 times or more within 2 seconds or when the arc duration is maintained for 4 seconds or more. If the tracking signal continues for 2 seconds or more, tracking is performed. Diagnose as occurring.

The remote monitoring device determines the shape of the arc by processing the transmitted data for each information or use.

100: abnormal detection device
110: arc detection unit
111: arc sensor
120: tracking detection unit
121: tracking sensor
130: digital signal processing unit
140: communication unit
150: alarm means
160: display unit
170: power supply
180: self-diagnosis

Claims (6)

An ultraviolet sensor for detecting ultraviolet rays generated by discharge in the switchgear, a shaping circuit for converting an arc signal output from the ultraviolet sensor into a logic signal, and an arc for counting the number of arc occurrences by counting pulses of the shaped arc signal An arc detector comprising a counter, a pulse width converter for calculating a pulse duration of the shaped arc signal;
A tracking detection unit having a plurality of current sensors for measuring currents of R, S, and T phases of the live switchboard;
Periodically checking the voltage of the pulse transformer of the ultraviolet sensor to diagnose that the ultraviolet region detection accuracy of the ultraviolet sensor is lowered when the pulse transformer voltage falls below the minimum discharge start voltage, and the voltage level of the signal input to the current sensor A self-diagnosis unit for diagnosing an abnormality in the current sensor when periodically monitoring and maintaining it for a predetermined time below a reference value;
Detects the arc signal and the tracking signal through the arc detector and the tracking detector, and analyzes the detected signals to diagnose the occurrence of arc and tracking, generate an alarm according to the diagnosis result, and transmit the digital signal to a remote monitoring device. An abnormality detection apparatus of a switchgear comprising a processing unit. The method of claim 1, wherein the ultraviolet sensor,
A waveform generator configured with an operational amplifier to generate a triangular waveform,
And a pulse transformer which is driven by the generated triangular waveform and generates a DC high voltage to supply the UV sensor to the ultraviolet switch. The method of claim 1, wherein the arc counter,
And outputting an arc generation signal if the number of arc generations is equal to or greater than a threshold value. The method of claim 1, wherein the digital signal processing unit,
The apparatus for detecting abnormality of switchgear according to claim 4, wherein a fast Fourier transform operation is performed on the arc signal to calculate detection elements such as a high frequency component, a peak value, and an effective value of the arc signal. The method of claim 1, wherein the digital signal processing unit,
And a fast Fourier transform operation of the tracking signal to calculate detection elements such as an effective value, a current slope, a short circuit current, a current peak value, and an average value of the tracking signal. The method of claim 1,
And an alarm means for outputting an alarm according to the control of the digital signal processor.

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