RU2598037C1 - Method of transmitting and receiving relay protection signals and universal device for implementation thereof - Google Patents

Abstract

FIELD: energy.

SUBSTANCE: use: in electric power engineering. Method of transmitting and receiving relay protection signals comprises an independent, simultaneous transmitting two signals, one of which provides selectivity of protection action and is transmitted with carrier frequency: blocking or permitting, and the other signal, intended for accelerating protection action, is transmitted in the form of a n-command or a control signal. To ensure selective action of relay protection with high-frequency blocking (HFB), a signal is continuously transmitted from one of carrier frequencies: blocking or permitting, and while the phase differential protection (PDP) a signal is transmitted by manipulation of these frequencies, regardless of the protection type, HFB or PDP a signal of protection action acceleration is transmitted by amplitude modulation of any carrier frequency: blocking or permitting, each n command of protection action acceleration corresponds to a certain frequency of modulating signal from a common set of predetermined frequencies F₁-F_n, and a signal with frequency F₀ acts as a control signal. When receiving an integral signal supplied from a high-frequency channel passes through the filter of preliminary selection and an analogue-digital converter, then it arrives to inputs of two receivers, one of which receives a frequency-modulated signal, other recieves an amplitude-modulated signal, a signal is detected and filtrated in each receiver.

EFFECT: reduced mutual influence of two useful signals while their simultaneous transmitting, simplification of design and improved reliability of the device.

2 cl, 1 dwg

Description

The claimed group of inventions relates to the electric power industry, in particular to the field of high-frequency (RF) relay protection of power lines, and can be used as a universal tool for equipping RF channels, which can comprehensively provide the requirements for selectivity and speed of RF protection built on various elemental base and implementing various work algorithms, including:

- differential phase protection (DFZ);

- directional and distance protection with RF lock (VCHB);

- distance and current protection with tele acceleration;

- protections using tele-off signals.

High-frequency (HF) communication channels over power lines remain the main means of organizing technological communication for transmitting HF protection signals and command signals from emergency control automation. When taking into account a set of indicators, the RF channels are the most effective solution, because, at lower implementation costs, they have a sufficiently high reliability and provide the most stringent requirements for the signal transmission time.

The main components of the RF channel are: connection equipment (arresters with tuning elements, communication capacitors, connection filters) and terminal equipment, which include: RF protection signal transceivers, as well as devices for transmitting alarm signals and commands, including tele acceleration commands (TU) or TV shutdown (THAT).

To exclude the possibility of mutual influence of RF channels (many existing and newly designed) allows compliance with the principle of frequency separation of channels. The terminal (channel-forming) equipment in the general high-frequency range is allocated a certain frequency band for transmitting and / or receiving signals. The elementary part of the general HF range has a width of 4 kHz (IEC Standard: IEC 60834-1: 1999. Teleprotection equipment of power systems - performance and testing. Part 1: Command systems.).

The rational use of the common high-frequency range is facilitated by the use of terminal equipment occupying only one elementary frequency band (4 kHz) and

providing the ability to transmit several signals for various purposes, and the possibility of independent, including simultaneous, transmission of these signals.

In general, to relay protection (RE), technical requirements are imposed on four basic criteria for the quality of functioning: selectivity, speed, sensitivity and reliability. In some cases, the protection of overhead lines must act without delay and with absolute selectivity. Protections with absolute selectivity act on tripping only if the damage occurred within the protected zone - the section of the electrical network.

A high-voltage power transmission line (OHL) is a part of an electric network with two-way power and, as a rule, it is protected by two identical sets of relay devices located at opposite ends of the OHL.

To ensure absolute selectivity and maximum speed of power line protection, the measuring and logical parts of protection half-sets should receive information from the other side of the overhead line through special communication channels, among which the RF channels are most widely used.

All types of signals transmitted in the communication channels between the half-sets of REs of opposite ends of the protected overhead lines can be divided into two main groups according to their purpose.

The first group includes signals necessary for protection to determine the location of damage: in the protected zone (within the OHL) or outside the zone, that is, to ensure selective protection.

The second group includes signals that serve to increase the speed of protection, namely:

- enable signals, the reception of which serves as an additional confirming condition for the formation of a command to turn off the OHL switch;

- signals of tele acceleration (TU), the reception of which reduces the necessary time delay for forming a command to turn off the overhead line switch;

- Tele-shutdown (MOT) signals, the reception of which is the only condition for forming a command to turn off the OHL switch, regardless of the state of the protection half-set at this end of the OHL.

To transmit the signals of the first group, RF protection signal transceivers operating on the RF channel in the allocated frequency band of 2 kHz are used, and the transmission of the commands of the second group is carried out by alarm and command transmission devices on the second RF channel, for which the frequency band 4 should be allocated kHz Such a transmission scheme of overhead relay protection signals provides the possibility of independent, including simultaneous, transmission of two commands at once (one from each group), but it requires the organization of two communication channels, which leads to an increase in equipment costs and irrational use of the allowed frequency range .

The prior art device for transmitting and receiving signals of relay protection over power lines, consisting of a transmitter and a receiver, the transmitter comprising a master oscillator, a control unit, a power amplifier and a linear filter, and a receiver including an input filter, a high frequency amplifier, a frequency converter, intermediate frequency filter, detector and output amplifier (patent No. 2007005 for the invention "Device for transmitting and receiving signals of relay protection on power lines", filing date 10/13/1992, published but January 30, 1994).

The disadvantages of this device are due to the fact that the device is capable of transmitting only one type of overhead relay protection signals, namely the signals of the first group, which ensure the selectivity of the protection. To transmit a signal of tele acceleration (TU), for example, you will need to use an additional communication channel equipped with specialized terminal equipment.

The closest technical solution to the claimed method is a method for transmitting and receiving relay protection signals, including the transmission of a blocking signal, a control signal and the nth command, and in the absence of a short circuit, a signal is transmitted with a deviation of its frequency from the carrier frequency (f ₀ ) by the amount ( Δf), when starting directional protection with high-frequency blocking, the sign of the deviation of the frequency of the transmitted signal from f ₀ is reversed, when starting differential-phase protection, a two-position frequency-shift a calibrated signal with a frequency (f ₀ ± Δf), in the absence of relay protection commands (Δf ± F _k ), where F _k is the set value of the frequency shift of the control signal relative to the carrier, when the nth command (Δf = F _n ) is transmitted, where (F _n ) depends on the number of the nth command, and a blocking signal is received by determining the sign of the deviation of the signal frequency from f ₀ , and the control signal and the nth command are determined by determining the value (Δf) (Patent No. 2272348 for the invention “Method transmission and reception of relay protection signals and device (options) for its implementation ", filing date 07/20/2004 published on 03.20.2006).

The closest technical solution to the claimed device is a device for transmitting and receiving signals of relay protection, containing connected to the system bus interface unit equipped with a linear input and a linear output, an input circuit block, an output circuit block and a digital processing unit programmed with the possibility of forming on a linear output signal interface unit with a frequency deviating from the carrier frequency by an amount depending on the state of the input circuits, and with the possibility of changing the state of the output x circuits in accordance with the sign and the absolute value of the deviation of the signal frequency at the linear input of the interface unit from the carrier frequency, while the device is configured to phase shift the signal of the manipulation circuit and combine the phase-shifted signal with the output circuit signal corresponding to the opposite sign of the frequency deviation by linear input from the carrier frequency (see http://www.prosoftsystems.ru/products/product.htm?pid=294 AVANT RZSK relay protection signal transceiver).

The disadvantages of the known solutions are associated with the use of frequency manipulation (FSK) of the carrier both for the signal of the first group (signals necessary for protection to determine the location of damage) and for the signal of the second group (signals serving to increase the speed of protection), which leads to unjustified expansion of the spectrum formed to transmit a modulated signal. As a result of this, the transmission path of the device implementing this method is complicated, since it becomes necessary to use a shaping filter that limits the spectrum of transmitted signals and a powerful amplifier designed to operate in linear mode.

In addition, the disadvantages of the method include a significant change in the level of reception of one of the signals at the start and end of the transmission of another signal.

The technical result, which is achieved by the claimed group of inventions, is the optimal use of the allocated operating frequency band, reducing the degree of mutual influence of two useful signals while transmitting and detecting them in the receiving path, simplifying the design and improving the reliability of the device.

This result is achieved by the fact that the method of transmitting and receiving relay protection signals, including independent, including simultaneous, transmission of two signals, one of which ensures selectivity of the protection action and is transmitted with a carrier frequency: blocking or enabling, and the other signal designed to accelerate actions of protection, is transmitted in the form of an n-command or control signal, while to ensure the selective action of relay protection with high-frequency blocking (VCHB) carry out continuous transmission with a signal with one of the carrier frequencies: blocking or enabling, and with differential phase protection (DFD), the signal is transmitted by manipulating these frequencies, according to the invention, regardless of the type of protection VCHB or DFZ, the signal for accelerating the protection is transmitted by amplitude modulation of any of the carrier frequencies: blocking or resolution, wherein each of the n-action command acceleration protection corresponds to a certain frequency modulating signal from the set of predetermined frequencies F ₁ -F _n, and the signal of frequency F ₀ vypo It takes on the function of a control signal, when receiving, the integral signal coming from the RF channel passes sequentially through a pre-selection filter and an analog-to-digital converter, after which it goes to the inputs of two receivers, one of which receives a frequency-modulated signal, the other - amplitude-modulated at the same time, in each receiver, the signal is subjected to detection and filtering.

After digital processing, galvanic isolation, and conversion to the required voltage levels, the output signals from both receivers go to the relay protection terminal, where they are used to ensure selectivity and the required high-speed RF protection.

The specified technical result is achieved by the fact that the device for transmitting and receiving relay protection signals for implementing the inventive method includes an amplifying-converting signal transmission path and an amplifying-converting integral signal receiving path according to the invention, which are connected via relay blocks to the relay protection terminal and the RF channel -conversion path consists of a frequency synthesis unit generating amplitude-modulated and frequency-manipulated signals, and a linear filter connected to it through a signal amplifier, which is connected to a differential system, which is also part of the amplification-converter signal reception path and connected to the high-frequency channel and a preliminary selection filter, which, in turn, is connected to an analog-digital a converter associated with the inputs of two receivers, one of which is designed to receive the VCHB / DFZ signals and which uses a frequency-manipulated signal detector, and the second receiver, which uses they use a detector of amplitude-modulated signals; they are used to receive tele-acceleration / tele-trip signals, and each receiver is connected to a corresponding interface unit with a relay protection terminal.

The claimed group of inventions is illustrated by drawings, where

FIG. 1 is a schematic diagram of a universal device for transmitting and receiving signals of relay protection, where

1 - interface unit - control inputs interface for TU / TO signals;

2 - interface unit 2 - VCHB / DFZ signal transmission control interface;

3 - frequency synthesis block — carrier signal shaper and amplitude modulation signals;

4 - amplifier;

5 - linear filter;

6 - differential system;

7 - pre-selection filter;

8 - attenuator and analog-to-digital converter (ADC);

9 - detector of frequency-manipulated (FSK) signals - a receiver of VChB / DFZ signals;

10 - block interface with the terminal RZ - shaper of the resulting signal VChB / DFZ;

11 - detector amplitude-modulated (AM) signals - a receiver of signals TU / TO;

12 - a unit for interfacing with a terminal РЗ - an interface for the implementation of TU / TO commands.

The inventive universal device (transceiver) is designed to transmit and receive signals of relay protection of overhead lines. At each end of the overhead line, a relay terminal and a transceiver are installed. The transceiver is connected to the RF channel through a differential system 6, and to the terminal of the relay through the interface blocks 1, 2, 10, 12, performing galvanic isolation and conversion of signal voltage levels to standard values.

The implementation of the invention. The device allows independent, including simultaneous, transmission and reception of two signals, one of which serves to determine the location of damage on the overhead line: inside the protected area or outside its limits, and the second signal is a command to accelerate the protection.

At the command of the terminal РЗ supplied through the control circuit "Start", the signal transmission begins to ensure selective action of relay protection. In this case, through the control circuits of the TU / TO, the terminal РЗ can give a command to transmit one of the n-signals (n-commands), accelerating the action of protection. The first of the aforementioned signals is transmitted continuously, and when VChB is transmitted by one of two carrier frequencies: blocking Fn ₁ or allowing Fn ₂ , and during DFZ - by manipulation of the same frequencies. The second signal - the signal of acceleration of the protection action - is generated for transmission due to amplitude modulation of the carrier frequency signal Fн ₁ (Фн ₂ , / Фн ₂ ), while the modulating signal can take one of the frequency values, for example, Fo-Fn with the same amplitude depth modulation. A signal with a frequency Fo performs the function of a control (guard) signal, other signals with frequencies (F ₁ -Fn) transmit various n-commands to accelerate the protection.

From the relay protection terminal, the signals are sent to the corresponding interface units 1, 2, and then to the high-frequency signal generation unit 3, where the carrier signals are synthesized: blocking or enabling. The frequency synthesis unit 3 also generates a signal for modulating the carrier frequencies in amplitude. This signal is generated using n-control commands from the terminal РЗ, which enter synthesis block 3 through interface unit 1. Each of the n-commands, as well as the control security signal, corresponds to a certain frequency of the modulating signal from a common set of predetermined fixed frequencies.

The carrier frequency signal and the modulating signal are fed to the block of a powerful amplifier 4, where the amplitude modulation of the carrier signal and the amplification of the integrated signal are carried out.

Further, through the linear filter 5 and differential system 6, the integral signal is transmitted to the RF communication channel in the direction of the receiver of the remote half-set (to the other end of the overhead line).

All the while, the terminal РЗ does not give a command to transmit tele-acceleration (TU) / tele-trip (TO) signals, the amplitude modulation of the carrier signal is carried out by a fixed frequency signal corresponding to the control (security) signal Fo.

At the same time, the integral signal of the transmitter located on the opposite end of the overhead line section comes from the RF communication channel through the differential system 6 to the input of the receiving path, then to the pre-selection filter 7, after which it is sent to the attenuator and analog-to-digital converter 8. After of the conversion, the signal is simultaneously fed to the input of the HFB / DFZ signal receiver 9 and to the input of the TU / TO 11 signal receiver. In the HFB and DFZ signal receiver using the frequency detector algorithm, one of the two possible frequency carrier RF signal is currently being received at the input of the receiver: blocking or enabling, while the output of the receiver 9 generates a logical signal, respectively, low or high level, which then goes to one of the inputs of the interface unit 10. In this case, to another input interface unit 10, a MAN control signal is received from the terminal РЗ, from where this signal enters the delay line in order to obtain a time offset equal to the time of the total delay of the signals that occur during their passage into the track those transmissions, as well as in the receiving path of the device. After that, the MAN signal that has passed the delay line is summed with the output signal from the receiver 9, and the total signal is fed to the input of the terminal of the relay through the PFM circuit, thus providing a selective protection action. In the TU / TO 11 signal receiver, the AM signal is detected, its level is limited and decoded by narrow-band filters, each of which is tuned to a fixed frequency corresponding to a certain frequency of the n-command or control (security) signal. From the output of the receiver of signals TU / TO 11 through the interface unit 12, the received command is sent to the terminal РЗ for execution.

The device is equipped with hardware and software self-monitoring and diagnostics, has galvanic isolation on the control and signaling circuits (not shown in the drawing).

The implementation of the invention is confirmed by examples of specific performance. The device allows simultaneous independent transmission and reception of two signals, one of which serves to determine the location of damage on the overhead line: inside the protected area or outside its limits, and the second signal is a command to accelerate the protection.

Example No. 1

If the electric network is in normal operation mode (no damage), then a signal with a carrier frequency (Fн2) is established and continuously transmitted at the output of the synthesizer 3, regardless of which protection algorithm the terminal RE implements: VChB or DFZ.

Example No. 2

If the relay terminal operates according to the VChB algorithm, then if a damage occurs in the electric network outside the protection zone, the signal at the output of the synthesizer 3 will take the value of the carrier frequency Fн1 and the output circuit of the relay terminals to turn off the switches at both ends of the overhead line will be blocked. If damage occurs in the protection zone, the transmitters at each end of the overhead line will transmit signals with a frequency of Fn ₂ , while the protection will be allowed and the overhead line will be turned off by switches on both sides.

Example No. 3

If the relay terminal works according to the DFZ algorithm, then when a damage occurs in the electric network, the synthesizer 3 will generate a frequency-manipulated signal by switching the frequencies Fн1 and Fh2 in accordance with the state of the MAN signal received from the relay terminal.

The technical solution proposed for protection is universal and can be used for collaborative work with relay terminals using protection algorithms of both VChB and DFZ.

Thanks to the claimed invention, a narrower frequency spectrum of the modulated signal is provided, as a result of which an additional installation of a shaping filter for the transmitted signal is not required, which makes it possible to use a class D mode in the amplifier of the RF transmitter, which is characterized by a high specific power and high efficiency. In this case, multiple harmonic components of the signal are eliminated by the linear filter of the transmitter tuned to the frequency of the output signal, which allows not only to simplify the design of the signal transmission path and the device as a whole, but also to make it less energy-intensive and more reliable. Through the use of fundamentally different modulation methods, the degree of mutual influence of two simultaneously transmitted signals is reduced, which simplifies the implementation of the receiving path of the device.

Claims (2)

1. A method for transmitting and receiving relay protection signals, including independent, including simultaneous, transmission of two signals, one of which provides selectivity of the protection action and is transmitted with a carrier frequency: blocking or enabling, and the other signal, designed to accelerate the protection, is transmitted in the form of an n-command or control signal, while to ensure the selective action of relay protection with high-frequency blocking (VCHB), a signal is continuously transmitted from one of the carrier frequencies: blocking realizing or enabling, and in case of differential-phase protection (DPS), the signal is transmitted by manipulating these frequencies, characterized in that, regardless of the type of protection VCHB or DPS, the transmission of the acceleration signal of the protection is carried out by amplitude modulation of any of the carrier frequencies: blocking or enabling, at To this, each of the n-commands for accelerating the action of the protection corresponds to a certain frequency of the modulating signal from the general set of predetermined frequencies F ₁ -F _n , and a signal with a frequency F ₀ performs the function of a control signal, when receiving signal, the integral signal coming from the RF channel passes sequentially through a pre-selection filter and an analog-to-digital converter, after which it goes to the inputs of two receivers, one of which receives a frequency-modulated signal, the other - amplitude-modulated, with each receiver the signal is detected and filtered. 2. A device for transmitting and receiving relay protection signals for implementing the inventive method according to claim 1, including an amplifying-converting signal transmission path and an integral-converting integral signal receiving-amplifying path connecting via the interface blocks to the relay protection terminal and the RF channel, characterized in that the amplifier-converter path consists of a frequency synthesis unit that generates amplitude-modulated and frequency-manipulated signals, and connected to it through an amplifier the signal is a linear filter, which is connected to a differential system, which is also part of the amplification-conversion path of the signal reception and connected to the high-frequency channel and the pre-selection filter, which, in turn, is connected to an analog-to-digital converter connected to the inputs of two receivers, one of which is designed to receive VChB / DFZ signals and which uses a frequency-shift signal detector, and the second receiver, which uses an amplitude-modulated detector x signals teleuskoreniya serves to receive / transfer trip signals, wherein each receiver is connected to the corresponding interface unit with the terminal relaying.

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