KR100305921B1 - Test equipment for making of ground and short in a distribution system - Google Patents

Abstract

The present invention relates to a ground / short circuit test apparatus for a distribution system, comprising: a first circuit breaker (10) for controlling a three-phase AC input power; A first voltage / current detector 20 for detecting a voltage / current of the AC input power through the first circuit breaker 10; A first ground and short circuit section 30 for grounding and shorting the AC input power; A second circuit breaker 40 for interrupting DC input power; A second voltage / current detector (50) for detecting the voltage / current of the DC input power source through the second circuit breaker (40); A second ground and short circuit section (60) for grounding and shorting the DC input power; A control unit for controlling the blocking operation of the first and second blocking means, controlling the ground and / or short-circuit operation of the first and second ground / shorting means, and processing the detected voltage / current as digital data ( 80); A key input unit 90 for inputting various commands to the controller 80; An indicator (100) displaying the processed voltage / current digital data; And a communication means for communication between the control means and an external device, by simulating a ground fault and a short circuit test before collecting a new power distribution system including a new power supply device, and collecting fault data, thereby ensuring stability. It is effective to establish all kinds of measures.

Description

Test equipment for making of ground and short in a distribution system

The present invention relates to a ground fault / short circuit test apparatus of a distribution system, and more particularly, fault currents, harmonics, and ground faults in the event of a ground fault and a short circuit in a new energy power source such as a photovoltaic system, a wind power system, a fuel cell, or cogeneration. It can be used to collect grid data such as power factor and phase, and it is possible to check the correction value of the existing relay and find out the change value in advance when the existing system and the new power system are linked in various grid linkage operations. The present invention relates to a ground fault / short circuit test system for distribution systems that can be used to identify fault currents caused by ground faults and short circuits, and to establish technical protection systems for protection device design.

In response to global and global environmental issues, increased power consumption due to improved people's living standards, and the restructuring of the power industry, both domestic and foreign countries are spurring the development of alternative energy sources, namely new energy sources. It is a practical situation. At present, new energy power systems such as solar power, wind power, fuel cell power generation, bio, waste, solar power generation, and small cogeneration are being developed or promoted in Korea as well as developed countries. If it is a stopper and a rotor. The stopper includes a DC / AC converter and mainly generates DC power. In order to link this with a distribution system, a DC converter converts DC into AC, a synchronization circuit for synchronizing with a system, and a control circuit for controlling the whole. If the power source having such controller is connected to the distribution system, unexpected accidents, such as 1-line ground fault, 2-wire ground fault, line short circuit and 3-phase short circuit accident on DC and AC side, will occur. (Overcurrent protection, surge absorption, temperature sensing, etc.) can have a significant impact on the power system and / or power distribution system when operating in conjunction without sufficient technical review of these phenomena. Not only can the economic loss be destroyed, but it can also affect the life-threatening safety. . In addition, the rotor is largely divided into an induction machine and a synchronous machine, which, as described above, may also be used when a sufficient technical review of ground faults and short circuit accidents that may occur when the new energy power supply is connected to the distribution system is not performed. Problems can be caused.

On the other hand, the distribution system has a complex configuration, a variety of operating forms, and the characteristics of the configuration changes frequently, the protection scheme is very complex compared to the transmission system. In addition, since loads are very diverse and small distributed power supplies are expected to be operated in both directions in the future, network type operation is also expected, so a protection relay system having a different concept from that of the current dendritic distribution system is required. . In order to cope with such changes in the distribution system operating environment and power quality requirements, it is necessary to accurately identify the distribution system failure characteristics, develop a new protection relay system for the distribution system suitable for them, and establish various load and load power connection standards. In order to prepare, it is time to perform simulation and actual system linkage tests, ie ground and short circuit tests, and establish new protection coordination from the results. Overseas, research on power system failure phenomenon is actively conducted on the basis of the fault data accumulated in the past, the distribution of distributed power is active, and research on the protection coordination system with multiple functions is in earnest. On the other hand, a typical dendritic protection coordination system has been established in Korea, and there is no system operation data on a new power distribution system including a new energy source. On the other hand, research on the combined function protection coordination system is underway and the optimization of the reclosing method of transmission and distribution lines is also being conducted. The problem is that it is complex and it is almost impossible to obtain data on accidents in the distribution system such as ground faults and short circuits from the actual operating data, and even more difficult in the case of new energy sources, for which there is no linkage experience.

The present invention was created in order to verify and solve in advance the problems that may occur when the ground fault and the short-circuit event as described above, the purpose is to ground before the operation of the new power distribution system including the existing power system and new energy power source · Ground fault / short circuit test apparatus of distribution system that can establish various countermeasures for stability by simulating short test and collecting fault data accordingly.

1 is a block diagram of a ground / short circuit test apparatus of a power distribution system according to an embodiment of the present invention;

FIG. 2 is a circuit diagram for grounding and short circuiting of an AC input power supply including the first circuit breaker 10 of FIG. 1, a first voltage / current detector, and a first ground / short circuit section.

3 is a circuit diagram for grounding and short circuiting of a DC input power supply including the second circuit breaker, the second voltage / current detector, and the second ground and short circuit of FIG.

4 is a flowchart illustrating a method of operating a ground fault / short circuit test apparatus of a power distribution system according to the present invention.

※ Explanation of code for main part of drawing

10,40: breaker 11,12,13: AC disconnect switch

20,50: Voltage / Current Detector 21,51: Voltage Detector

22,52: current detector 30,60: ground / short circuit

31,32,33: AC short circuit generating switch 34: AC ground fault generating switch

41,42: DC disconnect switch 61,62: DC short circuit switch

63,64: DC ground fault switch 65: DC high speed breaker

Ground fault / short circuit test apparatus of the power distribution system according to the present invention to achieve the above object, the first blocking means for intermittent AC input power; First voltage / current detecting means for detecting a voltage and a current of the AC input power through the first blocking means; First ground / short circuit generating means for grounding and shorting the AC input power; Second blocking means for interrupting the DC input power; Second voltage / current detection means for detecting the voltage and current of the DC input power supply through the second blocking means; Second ground / short circuit generating means for grounding and shorting the DC input power; Control to control the blocking operation of the first and second blocking means, to control the ground and / or short-circuit operation of the first and second ground and short generation means, and to process the detected voltage and current into digital data. Way; Input means for keying various commands into the control means; Display means for displaying the processed voltage and current digital data; And a communication means for communication with the control means and an external device, each of which connects a distribution line from a power supply device to an input / output terminal and an external device of a distribution system, and moves a place to a necessary place. And short-circuit tests, and establish countermeasures such as reliability of the power supply and distribution system against ground faults and short-circuit accidents.

Hereinafter, a ground fault / short circuit test apparatus of a distribution system according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a ground / short circuit test apparatus for a distribution system according to an embodiment of the present invention, including: a first circuit breaker 10 for interrupting an AC input power of three-phase 60 Hz 380 V; A first voltage / current detector (20) for detecting the voltage and current of the AC input power supply through the first breaker (10); A first ground and short circuit section 30 for grounding and shorting the AC input power; A second circuit breaker 40 for interrupting a DC input power supply of 100 V to 600 V; A second voltage / current detector (50) for detecting the voltage and current of the DC input power supply through the second breaker (40); A second ground and short circuit section (60) for grounding and shorting the DC input power; An analog / digital (A / D) converter 70 for converting the voltage and current detected by the first and second voltage / current detectors 20 and 50 into digital signals; Controlling the blocking operation of the first and second breakers 10 and 30, controlling the ground and / or short-circuit operation of the first and second ground and short circuit sections 30 and 40, and the A / D converter. A controller 80 for processing the voltage and current digital signals provided from 70 into visually displayable data; A key input unit 90 for inputting various commands to the controller 80; An indicator 100 that visually displays voltage and current data processed by the controller 80 in Arabic numerals or bar graphs; And a serial communication unit 110 for data communication between the controller 80 and an external device.

FIG. 2 is a circuit diagram for grounding and short-circuit of an AC input power including the first circuit breaker 10, the first voltage / current detector 20, and the first ground / short circuit section 30 in FIG. 1. The first breaker 10 is a high speed fuse 14, 15, 16 connected in series with each of the disconnect switches 11, 12, 13 installed in each of the R, S, and T three-phase lines and the disconnect switches 11, 12, 13, respectively. In the first voltage / current detector 20, the AC voltage detector 21 is a transformer (T1, the primary winding is connected to the R, S, T three-phase line connected to the secondary side) T2) is installed to detect the secondary voltages of the transformers T1 and T2, and the AC current detector 22 is connected to each phase line so as to detect current of each phase line. In addition, it is configured to have a high frequency band capable of measuring the transition characteristics. In addition, the first ground and short circuit section 30 constitutes a circuit based on MCCB (magnetic switch) having a breaking capability of 4 kA in order to form a ground fault and short circuit tester of an equivalent line, and a short circuit provided in each phase line. The switch 31, 32, 33 and one end are connected to the output terminal of each short switch 31, 32, 32, and the other end is composed of a grounded ground switch 34. In addition, the input / output terminal is terminal-processed to facilitate the connection between the simulated distribution line and the external output device.

FIG. 3 is a circuit diagram for a ground fault and a short circuit of a DC input power supply including the second circuit breaker 40, the second voltage / current detector 50, and the second ground / short circuit unit 60 in FIG. 1. Provide a breakdown voltage of at least 5.4 kV between the circuit arrangement for earthing and short-circuit of the dc input power supply and the earth or peripherals. The second circuit breaker 40 is a high speed fuse 43 and 43 connected in series to each of the disconnect switches 41 and 42 and the respective disconnect switches 41 and 42 installed in the positive (P) line and the negative (N) line, respectively. The voltage detector 51 of the second voltage / current detector 50 is provided to detect the voltage between the PN lines, and the second ground and short circuit section 60 is provided on the P line and the N line, respectively. Short circuit switches 61 and 62 connected in series to the installed fuses 43 and 44, respectively, and one end is connected in series to the output terminal of the short switches 61 and 62, and the other end is a common grounded ground switch 63 and 64. And a DC high speed circuit breaker (DC HSCB) 65 having a 4kA breaking capability connected in series with the output terminal of the short switch 61 installed in the P-line. The current detector 52 of the second voltage / current detector 50 is installed between the other end of the DC high-speed circuit breaker 65 and the common contact of the short switch 62 and the ground switch 64. The current detector 52 has a large current measurement range of 5 kA or more and is configured to have a high frequency band capable of measuring transition characteristics. In addition, the DC power input terminal is configured to be easily connected to the DC side of the new energy power system, such as solar cell system, fuel cell system.

On the other hand, all protection devices of AC and DC ground / short circuit test devices, that is, overcurrent protection devices, surge absorbing circuits, fuses, and temperature sensing circuits, etc. are to be mutually protected to prevent malfunctions. The overcurrent protection device must be designed so as not to interfere with the operation of the peripheral device. The overcurrent protection device is designed by adding an overcurrent detection circuit having a time-limiting characteristic and providing the detection signal to the controller 80 when the overcurrent is detected, thereby providing the control unit 80. Ensure proper control of overcurrent protection. The surge absorber is provided as a circuit for surge protection of the device according to the present invention, and the surge protection capacitor and the non-inductive resistor circuit are protected by a fuse, and a device for sending an alarm upon opening the fuse is also preferably added. Do. Various fuses are designed and manufactured so that the micro switch operates and the indicator lights installed in the enclosure light up to make it easy to identify the point of failure and to send a signal to the supervisory control facility. In addition, a temperature sensing sensor is installed in the main part of the ground fault and short circuit test apparatus according to the present invention so as to protect the circuit against temperature.

4 is a flowchart illustrating a method of operating a ground fault / short circuit test apparatus of a power distribution system according to the present invention. Referring to the drawings, the operation of the present invention will be described.

First, check the off state of all the switches for blocking, ground and short circuit (S1), turn on the control power (S2), and then determine whether the input power is DC or AC (S3). ). When AC power is input, the AC ground / short circuit power supply and the disconnect switches 11, 12, and 13 of the first breaker 10 are turned on (S4), and the AC ground and / or are connected through the key input unit 90. Set the short mode and enter the execution time of the mode (S5). According to the mode setting through the key input unit 90, the controller 80 controls the on / off operation of the short switches 31-33 and the ground switch 34 in a proper combination to control the 1-wire and 2-wire grounds. , And terminate after performing line short or three-phase short (S6). On the other hand, when DC power is inputted, the DC grounding / shorting power supply and the cutoff switches 41 and 42 of the second circuit breaker 40 are turned on (S7), and the DC grounding and / or short circuiting is performed through the key input unit 90. Set the mode and enter the execution time of the mode (S8). According to the mode setting through the key input unit 90, the control unit 80 controls positively the on / off operation of the short switches 61 and 62 and the ground switches 63 and 64 to be positive or positive. After performing negative (-) ground, positive (+) or negative (-) paragraph, the process ends (S9).

As described above, during the ground and short-circuit mode, the first and second voltage / current detectors 20 detect the ground / short current of each phase line and the ground / short voltage between each line, and the detected voltage. The / current is input to the controller 80 through the A / D converter 170, the controller 80 controls the display 100 to display the detected voltage / current in Arabic numerals or bar graphs, etc. . In addition, the controller 80 is capable of data communication with an external device such as an upper system through the serial communication unit 110, and receives a command from an upper host as well as control of its own ground and short circuit. · Allows to perform various controls such as including a short.

As described in detail above, according to the ground fault / short circuit test apparatus of the power distribution system according to the present invention, it is possible to secure protection coordination technology against ground faults and short circuits of various power distribution systems, and to prepare for ground faults and short circuits when connecting new energy power systems. It is possible to develop a protection coordination technology, to identify the characteristics of grid failures necessary to improve power quality, and to facilitate the development of a new concept of reliable new power distribution grid protection coordination system suitable for a variety of complex distribution system operation types. .

Claims (8)

First interrupting means for interrupting AC input power; First voltage / current detecting means for detecting a voltage and a current of the AC input power through the first blocking means; First ground fault means for grounding or shorting the AC input power; Control means for controlling a blocking operation of the first blocking means, controlling a grounding and / or shorting operation of the first grounding / shorting means, and processing the detected voltage and current as digital data; Setting means for setting various commands to the control means; And And a display means for displaying the processed voltage and current digital data. The method of claim 1, And said setting means is a communication means for receiving communication data from the outside and applying it to said control means. The method of claim 1, And said first voltage / current detecting means has a high current range and has a high frequency band capable of measuring transition characteristics. The method of claim 1, The first ground fault and short circuit means is a ground fault switch of the distribution system, characterized in that it is composed of a short circuit switch installed on each AC three-phase line, and a single ground fault switch having one end connected to the output terminal of each short circuit switch and the other end grounded. Short circuit test device. Second blocking means for interrupting the DC input power; Second voltage / current detection means for detecting the voltage and current of the DC input power supply through the second blocking means; Second grounding / shorting means for grounding or shorting the DC input power; Control means for controlling a blocking operation of the second blocking means, controlling a grounding and / or shorting operation of the second grounding / shorting means, and processing the detected voltage and current as digital data; Setting means for setting various commands to the control means; And And a display means for displaying the processed voltage and current digital data. The method of claim 5, The second ground fault means is a short circuit switch respectively provided on a DC positive (+) and a negative (-) line, a ground fault switch having one end connected in series with the output terminal of the short circuit switch and the other end being common grounded, and the positive A grounding / short circuit test apparatus for a distribution system, comprising a DC high speed circuit breaker connected in series with an output terminal of the shorting switch installed in a line. The method of claim 5, And said second voltage / current detecting means has a high current range and a high frequency band capable of measuring transition characteristics. The method of claim 5, A circuit device for grounding and short circuiting of a DC input power source comprising the second interrupting means, the second voltage / current detecting means, and the second grounding / shorting means has an insulation withstand voltage between the earth and peripheral devices. Ground fault / short circuit test device of the distribution system.