JPS6152605B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a setting calculation device for a power system protection relay. A backup protection distance relay will be described as an example of the prior art. Distance relays for back-up protection function as a remote backup when the main protection relay is inoperable or the disconnector is inoperable, in other words, it accurately and quickly eliminates the accident area and minimizes the spread of the accident. It performs a blocking function, and is generally used in combination with various distance relays. Since the setting of this distance relay affects the backup protection function mentioned above, the determination of the setting value plays an extremely important role. However, the current setting values are often determined by the experience of maintenance personnel, and the systems that are subject to failure calculations that affect the setting are limited to a very small range around the relay installation point. Distance relays are inherently susceptible to the effects of power currents, arc resistance, shunt effects (circumvention of current due to branch points, etc.), and changes in system configuration. By performing fault calculations based on the situation (system configuration, power flow, etc.) and taking into account the system configuration that affects the setting, the optimal setting value according to the situation can be determined. Furthermore, it is also necessary to coordinate with the backup protection relay in front, rather than focusing only on the own terminal. However, today's power systems have many patterns of changes in system conditions, and because they constitute a complex loop system, there are many relays that must be coordinated. It is becoming completely difficult to manually determine a setting value that takes the situation into account. The present invention is a device that automatically obtains a setting value that is most suitable for the current system situation from the current situation of the power system that is the object of protection, the characteristics of the power system, the characteristics of the protection relay that is the protection means, and the settable range. The purpose is to improve the setting accuracy of protection relays, thereby contributing to improving the reliability of the power system and saving labor in power system operation. FIG. 1 and FIG. 2 respectively show the hardware equipment configuration and software main frame of the present invention. In FIG. 1, reference numeral 11 denotes a system information measurement/detection device that measures data in the equipment of the power system to be protected or reads the operating status of the equipment, and 12 indicates a system information measurement/detection device built within the system information measurement/detection device 11. information (generator voltage, active power, reactive power, transformer active power, reactive power, phase adjustment equipment capacity, tap value, opening/closing status of shield breaker and disconnector, etc.)
A system information transmitting device that inputs a signal, converts it into a signal suitable for transmission through a transmission path described later, and outputs the signal, 1
Reference numeral 3 denotes a dedicated communication line or public communication line (hereinafter referred to as a transmission line) for transmitting the signal output from the system information transmitting device 12, and 14 receives the signal transmitted on each transmission line 13, 15 is an electronic computer; 16 is data for storing system information, system characteristic data, relay characteristic data, failure calculation condition data, etc. to be described later; A storage device, 17 is an input device for setting data such as the installation point of the protection relay to be set, and 18 is a display device for displaying the setting values of various distance relays, which are the calculation results.
This is an output device for recording. Figure 2 is a diagram showing the main frame of the software, and in the figure,
14, 17, and 18 are the same as the system information receiving device, input device, and output device shown in FIG. 1, respectively.
20 is a system information storage unit that stores information on the current status of equipment in the power system to be protected, and 21 is a system characteristic data storage unit that stores the types of equipment in the power system to be protected, their connection relationships, and electrical constants. ,2
2 inputs the information stored in the system information storage unit 20 and system characteristic data storage unit 21 and automatically calculates the conditions for failure calculation (system configuration to be calculated and assumed failure point) necessary for setting the protection relay. A failure calculation condition creation unit 23 is a failure calculation condition creation unit 22 that creates
A failure calculation condition data storage section 24 stores the failure calculation condition data created in the failure calculation condition data storage section 24, a failure calculation section that inputs the information in the failure calculation condition data storage section 23 to perform failure calculations, and 25 a failure calculation condition data storage section 24 that stores the failure calculation condition data created in the failure calculation condition data storage section 24. 26 is a failure calculation result data storage unit that stores data on voltage and current of each equipment in the power system to be protected; and 26 is a relay characteristic data storage unit that stores relay characteristic data and settable range data of all protection relay installation points in the power system to be protected. The section 27 calculates the setting value (finally the tap value) of the protection relay to be set from the information in the failure calculation result data storage section 25 and the relay characteristic data storage section 26.
This is a settling calculation section that automatically determines the Next, the parts other than the electronic computer shown in FIG. 1 will be explained in detail. The system information measurement/detection device 11 measures generator voltage, active power, reactive power, transformer active power, reactive power, phase adjustment equipment capacity, tap value and transmission line active power, reactive power in the power system to be protected. It consists of a meter that measures power and bus voltage, and a detection device that detects the opening and closing status of the disconnector and disconnector. Measured values can be obtained as analog or digital information. In the system information transmitting device 12, the analog information is passed to the scanner via the analog information input converter, and the digital information is passed to the scanner via the digital information input converter.The scanner sequentially scans the input, and converts the analog information into is further converted by an A/D converter and passed as time-divided digital information to a transmission code converter, where the digital information is converted from parallel codes to serial codes, and finally modulated by a modulator and transmitted. The action is as follows. Transmission line 13
It is constructed by a wired transmission method such as a communication line or power line, or a wireless transmission method using microwaves. In addition, the transmission path is a dedicated communication line,
Any public communication line can be used. In the system information receiving device 14, the signal transmitted via the transmission path 13 is received by the demodulator, encoded, and passed to the receiving code converter, where it is converted from serial code to parallel code, and sent to the distributor. Therefore, the information is output to the system information storage section 20 (FIG. 2) of the electronic computer. Furthermore, each part of FIG. 2 will be explained in detail. There are different types of power system protection relays: main protection, back-up protection, distance relays, voltage relays, frequency relays, phase relays, which detect different physical quantities, and transmission lines, busbars, and transformers. There are many types of protection relays, including those for different target equipment, but here we will explain a distance relay for back-up protection of power transmission lines as an example. FIG. 3 is an impedance complex plan view showing relay characteristics and setting points of a distance relay for power transmission line backup protection. 31 represents the characteristics of the first stage distance relay, 32 represents the characteristics of the second stage distance relay, 33 represents the characteristics of the third stage distance relay, and 34 represents the characteristics of the fourth stage distance relay. X ₁ is the setting point of the first stage distance relay, X ₂ is the setting point of the second stage distance relay, M is the setting point of the third stage distance relay, Z
_AM and Z _ZL indicate the setting point of the fourth stage distance relay. Now, in FIG. 2, the system information storage unit 20 stores generator voltage, active power,
Stores the current information of reactive power and transformer active power, reactive power, phase modifier capacity, tap value and transmission line active power, reactive power and bus voltage, and opening/closing status of disconnectors and disconnectors. ing. The system characteristic data storage unit 21 stores information about what kind of equipment (generators, transformers, transmission lines, busbars, breakers, disconnectors, etc.) the power system to be protected consists of,
It memorizes how these equipments are connected to each other, and also stores the electrical constants of each equipment (generator, transformer, impedance of power transmission lines, etc.). When the protection relay to be set is designated by the input device 17, the failure calculation condition creation section 22 creates failure calculation condition data in the steps shown in the block diagram of FIG. stored in the system information storage unit 20

[Table] Note that FIG. 5 and Table 1 do not include all of the failure calculation condition data created by the failure calculation condition creation section 22. As will be described later in the explanation of the setting calculation unit 27, this is fault calculation condition data for setting the second stage distance relay shown in FIG. The failure calculation unit 24 calculates the measured values of the equipment in the protected power system stored in the system information storage unit 20, the types of equipment and their electrical constants, etc. stored in the system characteristic data storage unit 21. Based on the current system configuration and failure calculation condition data obtained by the failure calculation condition creation section 22, failure calculations for short circuits and ground faults are performed one by one for each failure point in each system configuration, and each facility is The voltage and current of (transformers, power transmission lines, bus bars, etc.) are calculated, and the calculation results are stored in the failure calculation result data storage section 25. The setting calculation unit 27 calculates the applicable setting based on the voltage and current of each equipment stored in the failure calculation result data storage unit 25 and the characteristics and settable range data of the protective relay to be set taken out from the relay characteristic data storage unit 26. Automatically calculate protection relay settings. FIG. 6 is a block diagram showing the functions of the setting calculation section, and the method of calculating the setting value will be explained below for each step. (First step) Information on the voltage and current of each facility calculated by the failure calculation creation unit 24 is retrieved from the failure calculation result data storage unit 25. (Second step) Relay characteristic data storage section 26
The characteristics and settable range data of the protection relay to be set are retrieved from . (Third step) From the data acquired in the first step, extract the values (voltage and current) necessary for setting the protection relay to be set, and calculate the impedance using the following formula. Taking phase A as an example, when there is a short circuit fault: Z _a = v _a / i _a When there is a ground fault: Z _a = v _a / i _a +N ₁ (3i ₀ ) + N ₂ (3i ₀ '
) (In the event of a ground fault, consider zero-sequence compensation from the line where the protection relay to be set is installed and its adjacent line.) Here, i _a : A-phase current of the line where the protection relay to be set is installed v _a : Protection to be set A-phase voltage i ₀ at the relay installation point: Zero-sequence current i ₀ ' of the installation line of the protection relay to be set: Zero-sequence current N ₁ of the line adjacent to the installation line of the protection relay to be set: In the relay characteristic data storage section 26 Stored zero-sequence compensation coefficient N ₂ of the reactance element: Zero-sequence compensation coefficient of the Moh element stored in the relay characteristic data storage unit 26 This fault impedance is calculated as the CT ratio stored in the relay characteristic data storage unit 26.・Using PT ratio data, impedance seen by the relay Z _Ry = Z
Find _a × (CT ratio/PT ratio). Z _Ry expresses the distance seen by the relay to the failure point, and the setting value is determined based on this impedance. Taking the setting of the second stage distance relay of a three-terminal system as an example, the second stage determines the setting value based on the distance seen by the relay at the time of the next bus fault, so the six types of relays shown in Table 1 are used. Impedance Z _Ry is obtained. (Fourth step) A setting target value is determined from the impedance seen by the relay determined in the third step. This algorithm differs depending on each relay element (meaning the 1st, 2nd, 3rd, and 4th stage distance relays), but if we take a 3-terminal system 2nd stage distance relay as an example, the third step The maximum value of the impedances observed by the six types of relays described above is determined as the setting reference value as follows. (Short circuit relay setting target value)
= K _s・(Setting reference value at the time of short circuit failure) (Setting target value of ground fault relay)
= K _G (setting reference value at the time of ground fault) K _s and K _G are setting coefficients, for example, K _s =
1.3, K _G = 1.5, etc. (Fifth step) The setting target value obtained in the fourth step is a continuous value having an impedance dimension, and is converted into a relay tap value. Since the tap value of the relay is a discrete value, it is necessary to select either the upper side or the lower side, but this algorithm also differs depending on each relay element. In the same example of the second stage distance relay as described above, it is necessary to reliably include the next bus fault, so a tap value greater than or equal to the set target value is selected. The above are the functions of the settling calculation section 27. Finally, the display/recording device 18 outputs the setting value and tap value for each relay element calculated by the setting calculation section 27 together with the information stored in the relay characteristic data storage section 26 in the form of a relay slip. This can be used as material for comparing and examining the settings. As mentioned above, the above explanation uses the power transmission line back-up protection distance relay as an example, but even if other equipment to be protected (transformer, bus bar, etc.) or the type of relay is different, the failure calculation conditions are mainly applicable. Creation part 2
The setting value can be obtained using the same method, except that the algorithm in the setting calculation section 27 is slightly different from that of the setting calculation section 2. As described above, according to the present invention, a
To quickly, precisely and automatically determine the setting value of a protection relay without expending much effort.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a typical hardware configuration that realizes the present invention, Fig. 2 is a main frame diagram of the software of the present invention, and Fig. 3 is a diagram showing the characteristics of the distance relay and the distance relay obtained by the present invention. Figure 4 shows a block diagram of the fault calculation condition creation section of the software mainframe. Figure 5 shows an example of a power system configuration showing examples of changes in failure points and system configuration. FIG. 6 is a diagram showing a block diagram of the setting calculation section of the main frame of the software. 11... System information measurement/detection device, 12... System information transmitting device, 13... Transmission path, 14... System information receiving device, 15... Electronic computer, 16... Data storage device, 17... Electronic computer 18... Output device as a peripheral device of the computer, 20... System information storage unit, 2
DESCRIPTION OF SYMBOLS 1...System characteristic data storage part, 22...Fault calculation condition creation part, 23...Fault calculation condition data storage part, 24...Fault calculation part, 25...Fault calculation result data storage part, 26...Relay characteristics Data storage section, 27... Setting calculation section.

Claims (1)

[Claims] 1 A system information measurement/detection device that measures data on the equipment in the power system to be protected and reads the operating status of the equipment, and is suitable for transmitting the system information obtained by this system information measurement/detection device. a system information transmitting device that converts the signal into a signal and transmits the signal;
A transmission path for transmitting the signal output by this system information transmitting device through a dedicated communication line or a public communication line, and a transmission line for receiving the transmitted signal, converting it into information that can be stored in the system information storage section of the computer, and outputting it to the computer. a system information receiving device that is installed in the electronic computer and stores information on the current status of equipment in the power system to be protected; A system characteristics data storage section that stores electrical constants, installation point information of protective relays specified by an input device provided as a peripheral device of a computer, the contents of the system information storage section, and the contents of the system characteristics data storage section. A failure calculation condition creation unit automatically creates the power system configuration and assumed failure points necessary for failure calculation, and a failure calculation condition creation unit that automatically creates the power system configuration and assumed failure points necessary for failure calculation, and according to the data in the failure calculation condition data storage unit determined by this failure calculation condition creation unit. A fault calculation unit that calculates the voltage and current of each equipment (transmission line, bus bar, etc.) in the power system by performing fault calculations, and a failure calculation unit that calculates the voltage and current of each equipment in the power system (power transmission lines, bus bars, etc.), and is installed in each equipment in the power system stored in the system characteristic data storage unit. a relay characteristic data storage unit that stores the characteristics and settable range of the protective relay;
a setting calculation unit that automatically determines a setting value of the protection relay from the voltage and current of each equipment in the power system calculated by the failure calculation unit and the characteristics of the protection relay to be set taken out from the relay characteristic data storage unit; ,
Consists of an output device equipped as a peripheral device of a computer to display and record the setting value of the protection relay determined by the setting calculation section, and provides online information on the equipment and equipment of the power system to be protected. A setting calculation device for a power system relay, characterized in that a setting value of a protection relay is automatically obtained using a computer from the characteristics of the power system, which is a power system, and the characteristics of a protection relay, which is a protection means.