KR200288242Y1 - The static condenser protection of a substation for digital voltage relay - Google Patents

Abstract

The present invention relates to a digital voltage relay for protection of substation ancestor capacitors to detect an unbalanced voltage caused by the failure of the ancestor capacitors in the power system and to apply a trip contact to the breaker (C.B) to prevent further failure of the sound ancestor capacitor.

In particular, in the digital voltage relay which can monitor and protect the faults of the ancestor condenser in the high voltage and extra high voltage lines, the CPU unit is provided to perform the control operation throughout the apparatus. Fault detection information storage unit that stores the information of the keyboard with key and fault voltage detection, RAM unit that stores relay system information (correction value), computer, and SCADA system. Communication module for communication connection, a relay output unit having a function of electrically connecting the CPU, the display for displaying the operation status of the device by numbers or letters, and the function of connecting each power source to operate each driver according to the selected function; Analog filter unit for filtering harmonics mixed in the input signal, and A / D for converting continuous analog signals into encoded digital signals. Designed by connecting the affected part to the CPU in an electric combination, it is not only secured the performance and reliability than the existing relay, but also required for the automation / unmanned construction by introducing the communication function with the SCADA system. to be.

Description

The condenser protection of a substation for digital voltage relay

The present invention relates to a digital voltage relay that performs a protective mission by detecting a differential voltage in a circuit using a voltage differential method in a static cond-enser protection applied to a high voltage and a special high voltage line. The present invention relates to a digital voltage relay for protection of substation ancestor capacitors by detecting an unbalanced voltage resulting from a failure of the ancestor capacitor and applying a trip contact to the breaker CB to prevent further failure of the sound ancestor capacitor.

In general, when the amount of electricity used by consumers increases, the voltage of the line decreases as the load increases, and it is known that an ancestor capacitor is installed in the substation to prevent such a voltage drop. Such ancestor condenser can be broken by any cause, and the main cause is electric shock, that is, shock by surge and mechanical deterioration due to electric deterioration and overheating and vibration. The voltage relay detects the voltage imbalance caused by the signal, and emits a signal after the breaker operating time is set according to the relative amount of the voltage difference caused by the failure of the ancestor capacitor.

Conventional voltage relays use electro-mechanical relays. These electromechanical voltage relays are based on the variation of eddy currents formed on an induction plate using an induction plate applying the principle of Arago. The operating time of the voltage relay is determined by the rotational force of the induction disk proportional to the amount of change and the force of the spring which suppresses the rotational force. The signal controlling the breaker (TRIP) of the breaker (CB) is used to control the malfunctioning device from the high or special It consists of a voltage relay with a blocking structure.

Current domestic technology uses electromechanical relays to produce and supply products with fault monitoring and detection functions for ancestor condensers, but its function is far behind the trend of current automation systems. Because of the control method by disc and spring driving, it does not come out accurate time-limiting characteristics, so the reliability is low.In the electromechanical relay, there is a problem that various technologies such as communication with the host side and remote control function cannot be realized. The failure signal information transmitted to the SCADA system is not equipped with modern technologies such as remote monitoring, communication function, and calculation function that can perform functions by parallel operation with an indirect auxiliary relay, and thus meet the requirements of the current technology. There was a problem.

The present invention was created in view of the above-mentioned problems, and its purpose is to apply the digital signal processing technology using a microcomputer to the static condenser protection system of the high voltage and the special high voltage line, In order to solve the reliability problem of electromechanical relays, and to realize various technologies such as communication with the host side and remote control functions, the present invention provides a digital voltage relay for protecting substation ancestor capacitors.

1 is an exemplary view showing the appearance of the digital voltage relay of the present invention,

Figure 2 is an internal configuration diagram of a digital voltage relay for protecting the ancestor capacitor to which the present invention is applied.

<Description of the code | symbol about the principal part of drawing>

10: filter and sample holding part, 20: A / D conversion part,

30: nV-SRAM for correction value storage, 40: CPU and peripheral circuits,

50: LCD and key operation unit, 60: relay output unit,

70: RS-485 communication unit, 80: RS-282 communication unit,

90: fault detection information storage unit.

The present invention for achieving the above object is a digital voltage relay that can monitor and protect the fault of the ancestor condenser of the high voltage and extra high voltage line, provided with a CPU unit for performing a control operation throughout the device, various functions and set values A keyboard consisting of a number of keys that can be selected and changed, a fault detection information storage unit that stores information on fault voltage detection, a RAM unit that stores system information (correction value) of the relay, and a computer or a scanner. (SCADA) Communication module for the communication connection with the system, the CPU electrically connected, the display to display the operation status of the device by numbers or letters, and the function to connect the power supply to operate each driver according to the selected function The analog output section and continuous analog signal filtering harmonics mixed with the relay output section and the input signal The A / D converter converts the encoded digital signal to the CPU in an electrical combination.

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

1 is an exemplary view showing the appearance of the digital voltage relay of the present invention, Figure 2 is an internal configuration diagram of a digital voltage relay for protecting the ancestor capacitor to which the present invention is applied.

As shown in FIG. 1, the external structure of the present invention is a large display (A) for viewing various information of the relay, B is a forward sheet (IOV) and one sheet (TOV) of the relay LEDs are visually informed of this with the display. Here, the one-sheet lip (TOV) is a relay that detects a fault voltage and immediately sends a breaker control signal after delaying a prescribed time for the magnitude of the fault voltage without sending out a breaker control signal. Refers to the detection of fault voltage and the immediate release of the breaker control contacts without time delay. In addition, C is a keyboard part that can freely set relays and correction values as key signals, and includes MENU, UP, DOWN, SET, and CLEAR keys, and D and E indicate when a CPU and power error of the relay occur. It is a function to inform alarm by lighting with LED (BUZZ). F is a RS-232 communication port, and is a port for short-range communication that has a function of connecting a computer to correct failure analysis and relay operation value. Unexplained G is a relay nameplate, it is desirable to use a shielding effect against the noise flowing into the product by using aluminum of 3t thickness.

On the other hand, the self-diagnosis function displays the various states and errors of the device, the alarm is given through the display (A) as a numerical value and a letter, and the error is displayed only when malfunctions, and automatically returns to the normal state when it recovers normally. In addition, it is desirable to have a WATCH DOG function in order to increase the safety and reliability of the system.

2 is a diagram illustrating the internal configuration of FIG. 1, and reference numeral 10 denotes an analog filter application circuit. Since the calculation algorithm of the relay is based on a sine wave of a power system fundamental frequency (60 Hz), frequency components other than the sine wave are input waveforms. If it is included in the calculation result, an error occurs in the calculation result, so that it is difficult to accurately determine the failure. Therefore, an analog filter is used to cut off some frequencies except the sine wave.

Reference numeral 20 is an A / D converter that converts an input analog signal into a digital signal. Generally, a harmonic component is generated due to transient harmonic components during system breakdown, so that harmonic components can be removed. In this case, since the digital filter program is built into the A / D converter 20 inside the relay, the operation of the relay is improved based on the fundamental frequency, thereby improving reliability of the relay operation. Here, the relay uses a 12-bit A / D converter 20, and in the sample hold circuit inside the A / D converter, the analog value output from the analog filter 10 is sampled at regular intervals. (SAMPLING) Holds the sampled value for a certain time. Since the voltage of each phase must be sampled at the same time in the calculation algorithm of this relay, it is natural to prepare by adopting a sample hold circuit for each input signal.

Reference numeral 30 is nV-SRAM, and all the correction values of the relay are stored in this RAM. Unlike general RAM, the stored information can be stored semi-permanently without losing information even if the power of the relay is cut off. 40 is a special semiconductor made of a nonvolatile element, and 40 is a digital arithmetic processing unit (CPU) and a peripheral circuit thereof, and a ROM built in a CPU that stores a CPU that performs an addition or decrement operation and its operation procedure (PROGRAM). ROM), A / D conversion data from the analog input section, RAM for temporarily storing data, etc., and the CPU and the peripherals connected by wires transmitting data control information such as buses. Circuit.

As an input signal, a system voltage, a state signal of a peripheral circuit, a correction value, and the like are received, and relay calculation processing is performed, and the result is output to a memory unit or an output unit.

In addition, 50 is a display (A) and KEY operation unit (C), which adopts a large-capacity liquid crystal panel, and is designed for easy reading of various numerical values and correction values. KEY operation (C) is easily operated while looking at the upper display. It is provided to be.

60 is a relay output section and consists of a circuit that controls the output contacts for information computed by the CPU 40. The relay output contacts consist of six (5 a contacts and 1 b contact) and CB It consists of TRIP, IOV ALARM, TOV ALARM, PRE ALARM, DC FAIL and RELAY ERROR.

Reference numeral 70 is a module configuration related to RS-485 communication, and it is possible to monitor various data and correction values by multi-drop in SCADA system and to remotely correct all correction values of the currently operating system. RS-232 communication is equipped with external and remote communication function to read or store all information of this relay using a computer. In particular, the FAULT RECODER information of the relay 90 is read to enable accurate fault identification and analysis using the failure analysis program of the relay.

That is, 90 is a fault detection information storage unit. When a fault voltage occurs and the relay operates to generate a breaker trip, all the information about the fault voltage is recorded in the fault recorder and the maximum number of fault records is 8 times. If the number of faults is more than 8 times, the first fault information is deleted sequentially and 8 times including new information is automatically saved. (FIF O: First In First Out) You can see the time, phase and voltage level of the fault. When using the fault analysis program on the computer using the RS-232 (80) communication port, the magnitude of the voltage waveform at the time of failure, harmonic analysis, time analysis, etc. DATA is stored to analyze various data.

As described above, the present invention improves the reliability of the product through digital operation processing that can detect failures much more accurately than the conventional electromechanical type, and has not previously existed the forward-slip function, the relay self-diagnosis function, and the detected failure. Built-in FAULT RECODER function to store voltage, communication function with SCADA system, RS-232 communication function to perform control and failure analysis of the internal system of the relay at a short distance by computer, and built-in relay's own test function are convenient. Even if the relay control power is temporarily cut off, the relay memorizes the correction value and the current time, and if the power is normal, it includes the function to continue the protective mission before the power failure without human intervention. have.

In addition, the conventional electromechanical relay had only one trip contact, so the method of reporting fault information to the SCADA system was primitive and occupied a lot of device layout space. However, this digital voltage relay uses a total of six contacts. Therefore, it is possible to conveniently output information about the items monitored by the relay, and the relay is not an electromechanical type which is mechanically driven inside the relay.

In particular, with the introduction of the Human Machine Interface (HMI) function, the user's convenience is further improved compared to the conventional technology, and the digital signal processing technology improves the reliability of the measurement and protection tasks much more accurately than the conventional relay, It guarantees the reliability of monitoring and protection of the ancestor condenser of the facility and has an effect on the construction of the substation unmanned system using the communication function with the SCADA system.

Claims (1)

In the digital voltage relay which can monitor and protect the fault of the static condenser of the high voltage and extra high voltage line, A sample and hold circuit is adopted for each input signal so that the voltage of each phase can be sampled at the same time.A filter and a sample that hold the sampled value for a certain time by sampling the analog value output from the analog filter at regular time intervals. The holding unit 10, the A / D conversion unit 20 having a built-in digital filter program and converting an analog signal into a digital signal, and all correction values of the relay are stored, and information is not lost even if the relay power is cut off. Correction value storage nV-SRAM 30 made of a nonvolatile element capable of storing information semi-permanently, a ROM embedded in the CPU storing the CPU and its operation procedure, and A / D at the analog input unit. It consists of converted data and RAM that temporarily stores data, and takes into account the system voltage, the status signals of peripheral circuits, and correction values as input signals, and relay operation processing. The CPU and peripheral circuit 40, which outputs the result to the memory unit or the output unit, and the large-capacity liquid crystal panel are adopted to easily read various numerical values and correction values. Relay output unit 60 consisting of a large-capacity LCD and key operation unit 50 provided for easy operation while looking at the upper display, and a circuit for controlling six output contacts for the information calculated by the CPU 40; It is a module configuration related to RS-485 communication and monitors various data and correction values by multi-drops in SCADA system, and reads all relay information using a computer by providing external and remote communication functions through RS-232 communication. Communication means (70,80) for storing or storing information, and a fault detection information storage unit for reading the fault information and identifying and analyzing the cause of the fault accurately using the fault analysis program of the relay ( 90) Digital voltage relay for substation ancestor condenser protection, comprising: