JPH0315236A - Protecting and monitoring system for transmission system - Google Patents

Abstract

PURPOSE:To permit the correct decision of the generating point as well as the substance of a trouble by a method wherein a quantity of electricity detector, measuring the conductor voltage, current and the like of a transmission line, converting data obtained by sampling them into digital signals and transmitting the coded signals to a receiving device on the ground through multiplex transmission, is attached between the spans of the transmission line. CONSTITUTION:A quantity of electricity detector ED is attached between a plurality of spans of transmission lines to detect the conductor voltage and current of respective phases of transmission lines. Data, obtained by sampling them with a predetermined period, are converted into digital signals while the signals are coded to transmit them to a receiving device RC on the ground through multiplex transmission. According to this method, not only the voltage and current under a stationary condition but also the same data upon generation of a trouble, which are changed momentarily, may be transmitted surely and correctly.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is a power transmission system protection and monitoring system that can accurately locate the point of occurrence of an accident on a multi-branch power transmission line and also accurately determine the nature of the accident at a monitoring station. Regarding.

(Prior Art) As devices for measuring fault points that occur in power transmission systems, various types of fault detectors, such as a pulse radar system, a surge reception system, and an impedance system, are used. but,
In any type of fault port cable, the error in measurement distance is as large as ±IKm, and the current situation is that it takes time and effort to find the fault point when performing maintenance, inspection, etc.

On the other hand, digital relays are becoming the mainstay of protection relays for protecting power transmission systems, replacing analog relays. Compared to analog relays, this digital relay enables the fault point to be located using the distance relay principle and the zero-sequence current shunt ratio, and also improves the selection of ground fault lines and the protection performance of high-resistance grounding systems. It has the advantage of being able to

However, conventional power transmission system protection systems obtain line voltage and current information from transformers and current transformers installed at substations, etc., and provide this information to digital relays. When protecting such a complex multi-branched power transmission system, it is difficult to accurately determine not only the fault point but also the details of the fault, such as the selection of fault lines.

By the way, recently, power transmission lines have been monitored and controlled using sensors that have the function of determining the line voltage, current value, phase, etc. of the power transmission system at the span level and transmitting this information to ground stations by radio waves, etc. A system is known (for example, Japanese Patent Laid-Open No. 60-43035).

Here, the outline will be described with reference to FIGS. 4 and 5. FIG. 4 shows a sensor module 40 installed in the span of a power transmission line 41. As shown in FIG. and n in both measuring parts.
1. An annular case 40a houses a phase difference measurement unit that performs predetermined signal processing on a fixed voltage and current to determine a phase difference, and is shaped on the inner outer circumferential surface of this case 40a. A transmission antenna 40c is attached to the capacitor 40b and a part of the outermost circumferential surface, and a mounting hub 40e is attached to the hollow circumferential surface of the case 40a via spokes 40d and supports the entire sensor module on the conductor of the power transmission line 42. We are prepared. In addition, in FIG. 5, each piece of information measured by the sensor module 40 is transmitted to the transmitting antenna 40.
c to the ground station. A receiver 42 is installed at this ground station, for example, a steel tower, and when each piece of information is received by this receiver 42 via a receiving antenna 43,
The information is transmitted via transmission link 44 to a central control station, not shown.

Next, various measurement principles by the sensor module 40 will be explained with reference to FIGS. 6 to 8. As shown in Figure 6, the line voltage is determined by detecting the charging current flowing through the stray capacitance between the sensor body (voltage detection plate) and the ground, adding this to the operational amplifier OA, and converting it into voltage. .

In this case, calibration depending on the installation location (usually ±0.5%) is required. Further, the line current can be determined by extracting the voltage generated in a solenoid coil L (Rogowski coil) wound around a hollow plastic tube and integrating it as shown in FIG.

In other words, the output voltage of the coil is proportional to the differential of the current (V1K-
Since Ndl/di, it can be calculated from the sine and cosine elements by Fourier analysis of the current signal that integrates this. In this case, the voltage and current signals are obtained by simultaneously sampling the voltage and current waveforms at intervals of 179 cycles based on the voltage waveform, as shown in Figure 8, but once for each cycle. Measurements are taken to vary the spacing over 9 cycles.

Here, the analysis of the Fourier component is performed by calculating the following equation.

VA-2/9ΣVs -cos (40◆S)VB-2
/9ΣVs -sIn (40◆S)IA-2/9ΣI
5 ・cos (40・S) IB-2/9ΣEs -s
ln (40・S) In this way, the voltage, current, and phase difference information measured by each sensor module 40 installed in each span of the power transmission line 41 are digitized and transmitted to each receiver on the ground side. The information is transmitted wirelessly at two-second intervals, and each receiver on the ground side receives this information and transmits it to a central control station, thereby monitoring and controlling the entire power transmission system.

(Problem to be Solved by the Invention) However, the power transmission system monitoring system as shown in the above publication does not allow monitoring of the entire power transmission system in a steady state,
For the purpose of control, the voltage, current, phase difference information, etc. measured by the module sensor are transmitted to the receiver on the ground side.
It is not possible to transmit information such as current that changes from moment to moment to a receiver on the ground side. In other words, in the above-mentioned module sensor, the voltage and current are divided into 9 cycles based on the voltage waveform, and simultaneously measured once for each cycle and transmitted to the ground station, which cannot be applied in the event of an accident.

The present invention is capable of accurately determining the point of occurrence of an accident and the nature of the accident even in a complex branching system such as a multi-branch power transmission system, and is also capable of monitoring the power transmission system from a steady state to an unsteady state. The purpose is to provide a power transmission system protection and monitoring system that can be used.

(Means for Solving the Problems) In order to achieve the above objects, the present invention provides a power transmission system protection and monitoring system that monitors the status of the power transmission system and determines the fault point when an accident occurs. Electrical quantity detectors are installed in each of the multiple spans and transmit information obtained by detecting electrical quantity, and electrical quantity detectors are installed corresponding to each electrical quantity detector on the ground side and transmit information from the corresponding electrical quantity detector. A receiving device that receives information, a comprehensive transmitting device that sequentially transmits the information received by these receiving devices to the monitoring station, and a comprehensive receiving device that is provided at the monitoring station and sequentially receives the information transmitted from the comprehensive transmitting device. device, and a digital relay section that takes in the information received by the general receiving device and determines whether or not there is an 11 fault in the power transmission system through digital arithmetic processing, and the electric quantity detector a voltage 71FI constant section that measures the voltage of the line conductor; a current measurement section that measures the current flowing through the line conductor;
Sampling means for sampling the voltage and current signals measured by the J constant section and the current measuring section, respectively, at a predetermined sampling frequency; a signal processing means for synthesizing, digitally converting, and encoding the signals sampled by the sampling means; The receiving device comprises a transmitting means for transmitting a signal encoded by a signal processing means, and upon receiving the signal transmitted from the transmitting means of the electric quantity detector, the receiving device decomposes the signal, arranges the signals, and transmits the composite signal. It consists of a demodulating means for inputting to the transmitting device.

(Function) Therefore, in a power transmission system protection and monitoring system with such a structure, the conductor voltage, current, etc. of the power transmission line are measured, the data obtained by sampling these is converted into digital data, and the code is converted into a code. Electrical quantity detectors are installed in the spans of power transmission lines for multiplex transmission to receiving equipment on the ground, so voltage and current change from moment to moment, not only during steady state conditions, but also when an accident occurs. Data can be sent reliably. In addition, when the information from the electrical quantity detectors installed in multiple spans of the power transmission line is received by each receiving device installed on the ground side, the signals are composited, aligned, and sequentially transmitted to the monitoring station. However, when the monitoring station receives that data, it feeds it to the digital relay section, which performs the digital/7A arithmetic processing necessary to determine the presence or absence of an accident, and makes a comprehensive determination, so it can be used in cases such as branch power transmission systems. However, it is possible to determine the point of occurrence of an accident for each span of the power transmission line, and the details of the accident can be determined with high precision.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of one phase of electrical quantity detectors ED installed between the spans of each phase of the power transmission line.

In Figure 1, 1 is a voltage detection plate that detects the voltage between the line conductor and the ground, 2 is a solenoid coil equivalent to a Rogowski coil that detects the current flowing in the line conductor, and these voltage detection plate 1 and solenoid coil 2 are The constant principle of voltage and current according to 71'll1 is the same as that described with reference to FIGS. 6 and 7, so its explanation will be omitted here. The voltage signal and current signal detected by the voltage detection plate 1 and the solenoid coil 2 are amplified by amplifiers 3a and 3b, and further passed through bound bus filters 4a and 4b to a sampling hold circuit 5.
Added to a, 5b. These sampling and holding circuits 5a and 5b sample the voltage signal and current signal at a predetermined sampling period (generally 60Hz 150H
z, the electrical angle is 30°), and its output signal is applied to the multiplexer 6. This multiplexer 6 sequentially switches and synthesizes the output signals of the sampling and hold circuits 5a and 5b by switching, and the synthesized signal is converted into a digital signal through an analog/digital (A/D) converter 7. The digital signal converted by this A/D converter 7 is applied to an encoding circuit 8, and the encoded signal here is subjected to FM modulation and multiplex transmission from an oscillator 9 to a receiving device on the ground side, which will be described below. Ru. In this case, in order to prevent interference with other electrical quantity detectors ED, FM modulation is performed at a pre-assigned frequency.

Note that the amplifier 3c, bound pass filter 4c, and sampling hold circuit 5C in the figure are provided as spares.

Although we have described the case in which the electrical quantity detector ED with such a configuration is installed in one phase of a certain span of a power transmission line, in reality it is installed in a plurality of units in each phase of a power transmission line in a power transmission system as shown in Fig. 3. These are installed in each span.

Figure 2 shows a system configuration in which receivers RC are installed on the ground side of multiple spans and the data received by each receiver RC is transmitted to a part of the digital relay on the monitoring station side via the integrated transmitter/receiver. It is a block diagram. In Fig. 2, IOR, 10S, and IOT are receivers corresponding to each of the three phases that receive radio waves transmitted from the electrical quantity detector ED in a certain span, which is attached to each phase of the power transmission line. The signals received by each receiver 10R, IOS, and IOT are applied to decoding circuits 11R, IIS, and IIT, and the decomposed signals here are applied to signal alignment circuit 12. The signal alignment circuit 12 aligns the composite signal in the order of R, S, and T phases, and inputs the signal to the integrated transmitter 13. The integrated transmitting device 13 also receives inputted data whose signals have been aligned in the same manner as described above from the receiving devices RC corresponding to the electrical quantity detectors ED in other spans. Then, this general transmitter 13 sequentially switches the input data from each receiver RC and transmits it by radio waves. On the other hand, on the monitoring station side, signals sequentially transmitted from the general transmitter 13 are sent to the general receiver 14.
is sequentially received using direct memory access (
DMA) 15 and delivered to the digital relay section. The processing in this digital relay section is the same as the configuration of a general digital relay. That is, as shown in the right half of FIG. 2, a part of the digital relay monitors the status of the digital arithmetic processing unit 16, the random access memory (RAM) 17 into which data transferred from the DMA 15 is written, and the power transmission line. A read-only memory (ROM) 18 stores monitoring programs for manual inspection and inspection programs for manual inspection, a setting section 19 for setting relay operation settings and checking changes, and storing device information such as external contacts. input device (D/I) 20, tri. It consists of an output device (D/O) 21 that outputs program output and automatic monitoring results to the outside, and an interrupt reception unit 22, which are connected by a data bus 23. In this case, when an interrupt request is input, the interrupt reception unit 22 causes the digital arithmetic processing unit 16 to temporarily suspend program execution, and then moves to another program so that it can be resumed later. can be accepted at the same time. For example, after the execution of the relay calculation program ends, the automatic monitoring program is repeated until the next relay calculation start interrupt occurs, but when a manual inspection interruption occurs, the automatic monitoring program is interrupted and the inspection program is executed.

In this way, in this embodiment, the electric quantity detector E shown in FIG.
D is attached to each of multiple spans of a power transmission line to detect conductor voltage and current in each state of the transmission line, sample these at a predetermined period, and convert the obtained data into digital data, encode it, and receive it on the ground side. Since multiplex transmission is performed to the device RC, it is possible to reliably transmit data that changes from time to time, such as voltage and current, not only in a steady state but also in the event of an accident.

In addition, when the information from the electric quantity detectors ED installed in each of the multiple spans of the power transmission line is received by each receiving device RC installed on the ground side, the signals are composited, the signals are aligned, and the information is sent to the monitoring station. When the data is received at the monitoring station, it is sent to the digital relay section, which performs the digital calculations necessary to determine whether an accident has occurred, and makes a comprehensive determination. It is possible to determine the details of the accident on a span-by-span basis, and the details of the accident can be determined with high accuracy. In particular, it is possible to easily and accurately determine the point of occurrence of a fault in a multi-branch power transmission system, which has been difficult with conventional digital relays, and to select a multi-branch fault line with high resistance grounding.

Furthermore, since the electrical quantity detectors ED installed in multiple spans also measure voltage and current information during steady state, the status of the power transmission system can be determined by determining the information at the digital relay section at the monitoring station. Needless to say, it is possible to monitor comprehensively.

In the above embodiment, a case has been described in which information is transmitted by radio waves between the comprehensive transmitting device 13 on the ground side and the comprehensive receiving device 14 on the monitoring station side. You may also do so.

Furthermore, although the voltage and current information detected by the electrical quantity detector ED is transmitted to the ground-side receiver rjiRCI by radio waves, this may also be transmitted by infrared rays. In this case, the infrared transmission method can be implemented by employing a method generally used in home appliances, such as televisions, in which the transmission carrier frequency is modulated at 455 kHz and transmitted.

The difference here from when a wireless system is adopted is that when the surface of the infrared ray generating part installed in the electric i-detector ED becomes frozen or snowed during winter or other seasons, the receiving device RC on the ground side There is a concern that the level of infrared rays transmitted towards the target will decrease. Therefore, in preparation for such a case, the receiving device RC on the ground side is equipped with a device that can emit an infrared beam. When the infrared rays transmitted from the ED are received by the receiving device RC on the ground, if the intensity of the received infrared rays becomes weak and the reception reliability is reduced, the infrared beam is sent from the receiving device RC on the ground to this part. All you have to do is shoot it to remove the deposits.

(Effects of the Invention) As described above, according to the present invention, information on line voltage and current in multiple spans of a power transmission line is measured by an electric FFI detector, and accident information that changes from time to time is collected on the ground side. The transmission is transmitted from the transmitting device to the monitoring station, and the state of the power transmission system is comprehensively determined by the digital relay section, so even in a system with complex branches such as a multi-branch power transmission system, the point and details of the accident can be determined. It is possible to provide a power transmission system protection and monitoring system that can accurately determine the power transmission system and monitor the power transmission system from a steady state to an unsteady state.

[Brief Description of the Drawings] Fig. 1 is a block diagram showing the configuration of an electrical quantity detector in an embodiment of the power transmission system protection and monitoring system according to the present invention, and Fig. 2 shows the data transmission system and Figure 3 is a block diagram showing the configuration of the digital relay section, Figure 3 is a system diagram showing a row of multi-branch power transmission lines, Figures 4 and 5 are diagrams for explaining conventional module sensors, and Figure 4 is FIG. 5 is a perspective view showing the external appearance of the module sensor, and FIGS. 6 to 8 are diagrams illustrating the principle of each 4P1 fixed part of the module sensor. ED... Electricity detector, RC... Receiving device, 1...
・Voltage plate, 2... Solenoid coil, 3a, 3
b...Amplifier, 4a, 4b...Bypass filter,
5a, 5b... Sample and hold circuit, 6... Multiplexer, 7... A/D converter, 8... Encoding circuit, 9... Oscillator, 10R, 105, IOT... Receiver , 11R, IIS, 1.1T...complex circuit, 1
2... Signal alignment circuit, 13... Comprehensive transmitter, 14
... General receiving device, 15 ... Direct memory access, 16 ... Digital arithmetic processing section, 17 ... Random access memory, 18 ... Read only memory, 19 ... Setting section, 20 ...・Input device, 21...
- Output device, 22... interrupt reception unit.

Claims (1)

[Scope of Claims] In a power transmission system protection and monitoring system that monitors the status of a power transmission system and determines the fault point in the event of an accident, information obtained by detecting electrical quantities provided in each of a plurality of spans of power transmission lines A receiving device is provided on the ground side corresponding to each electrical quantity detector and receives information transmitted from the corresponding electrical quantity detector, and information received by these receiving devices. a comprehensive transmitting device that sequentially transmits the information to the monitoring station side; a comprehensive receiving device provided on the monitoring station side that sequentially receives the information transmitted from the comprehensive transmitting device; and a comprehensive receiving device that takes in the information received by the comprehensive receiving device. A digital relay unit that determines whether there is an accident in the power transmission system through digital calculation processing; a current measuring section, a sampling means for sampling the voltage and current signals respectively measured by the voltage measuring section and the current measuring section at a predetermined sampling period; a signal sampled by the sampling means is synthesized, digitally converted and encoded; and transmitting means for transmitting a signal encoded by the signal processing means, and when the receiving device receives the signal transmitted from the transmitting means of the electric quantity detector, it decodes the signal and converts the signal into a signal. 1. A power transmission system protection and monitoring system comprising demodulation means that are aligned and input to the general transmitter.