CN107069678B - A kind of electric line thread-breakage protecting and system - Google Patents
A kind of electric line thread-breakage protecting and system Download PDFInfo
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- CN107069678B CN107069678B CN201710172797.7A CN201710172797A CN107069678B CN 107069678 B CN107069678 B CN 107069678B CN 201710172797 A CN201710172797 A CN 201710172797A CN 107069678 B CN107069678 B CN 107069678B
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- power transmission
- distribution line
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
- H02H7/261—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured involving signal transmission between at least two stations
- H02H7/262—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured involving signal transmission between at least two stations involving transmissions of switching or blocking orders
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
- G01R31/085—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution lines, e.g. overhead
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/0007—Details of emergency protective circuit arrangements concerning the detecting means
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/22—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for distribution gear, e.g. bus-bar systems; for switching devices
- H02H7/226—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for distribution gear, e.g. bus-bar systems; for switching devices for wires or cables, e.g. heating wires
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Emergency Protection Circuit Devices (AREA)
Abstract
The invention discloses a kind of electric line thread-breakage protecting and systems, which comprises by least the one of an electric line at least phase line as transmitting an injection monitoring signals；As point of collecting mail the monitoring signals are received for the electric line with a little corresponding predeterminated position that transmits；Do not receive the monitoring signals in the collection of letters point, and the electric line main protection it is not operating when, determine and described collect mail point and the electric line that transmits between a little breaks；It collects mail point described and after the electric line that transmits between a little breaks, starts the breaking protection of the electric line.
Description
Technical Field
The invention relates to a line maintenance technology, in particular to a power transmission and distribution line disconnection protection method and system.
Background
The transmission and distribution line is used for transmitting and distributing electric energy, is usually erected between a power plant and a regional transformer substation, and between the regional transformer substation and the regional transformer substation, is called as a transmission line, and is characterized by high line voltage, long transmission distance and large transmission capacity. The line between the line supplying power from the grid system to the user and the urban and rural transformer station for distributing the electrical energy is called a distribution line. Various faults often occur in the process of transmitting and distributing electric energy in both transmission lines and distribution lines, wherein the disconnection fault of the transmission and distribution lines is one of the faults which are difficult to distinguish, and has larger consequences.
In the prior art, an asymmetric component configuration zero negative sequence element can be used for identifying the line break fault of the power transmission and distribution line, and line protection is started by a differential protection or longitudinal distance protection method of a power system; however, the line break identification in this method is greatly affected by the operation mode of the power system and the structure of the power grid, and the accuracy of the line break identification is low, so that the line protection cannot be implemented well.
In the prior art, the electric quantity characteristics generated by the open-circuit voltage after the power transmission and distribution line is disconnected can be used for identifying the disconnection, and corresponding line protection is started; however, when the power transmission and distribution line is in no-load or light-load, the corresponding line protection cannot be started in time due to the difficulty in accurately identifying the broken line, and because the open-circuit voltage is very small, the electric quantity of the power transmission and distribution line may not be changed basically before and after the broken line.
When the line is broken and the existing line main protection can not act, the method brings great harm to the stable operation of the power system and also brings potential safety hazards to users.
Disclosure of Invention
In view of this, the embodiments of the present invention are intended to provide a method and a system for protecting a power transmission and distribution line from disconnection, which can accurately and quickly start the disconnection protection when a disconnection fault occurs in the power transmission and distribution line.
In order to achieve the purpose, the technical scheme of the invention is realized as follows:
the embodiment of the invention provides a power transmission and distribution line disconnection protection method, which comprises the following steps:
injecting a monitoring signal into at least one position of at least one phase line of the power transmission and distribution line as a transmitting point;
receiving the monitoring signal by taking a preset position corresponding to the transmitting point in the power transmission and distribution line as a receiving point;
when the receiving point does not receive the monitoring signal and the main protection of the power transmission and distribution line is not operated, determining that the power transmission and distribution line between the receiving point and the transmitting point is broken;
and starting the disconnection protection of the power transmission and distribution line after the power transmission and distribution line between the receiving point and the transmitting point is disconnected.
Preferably, the injecting the monitoring signal into at least one position of at least one phase line of the power transmission and distribution line as a signaling point includes:
and injecting a monitoring signal with a frequency different from the self electric energy frequency of the power transmission and distribution line by using at least one position of at least one phase line of the power transmission and distribution line as a transmitting point.
Preferably, after injecting the monitoring signal into at least one position of at least one phase line of the power transmission and distribution line as a signaling point, the method further comprises:
and carrying out impedance matching on the monitoring signal, and enhancing the transmission power of the monitoring signal.
Preferably, before the receiving the monitoring signal by using a preset position corresponding to the transmitting point in the power transmission and distribution line as a receiving point, the method further includes:
and filtering the monitoring signal, and filtering the power frequency quantity and harmonic signals of the power transmission and distribution line.
Preferably, the starting of the line break protection of the power transmission and distribution line comprises:
and after the power transmission and distribution line between the receiving point and the transmitting point is broken, the circuit breakers at all ends of the power transmission and distribution line are disconnected in a delayed way.
The embodiment of the invention also provides a power transmission and distribution line disconnection protection system, which comprises a transmitting unit, a receiving unit and a protection unit; wherein,
the transmitting unit is used for injecting monitoring signals into at least one position of at least one phase line of the power transmission and distribution line as a transmitting point;
the receiving unit is used for receiving the monitoring signal and determining the connection and disconnection of the power transmission and distribution line between the receiving point and the transmitting point;
and the protection unit is used for starting the disconnection protection of the power transmission and distribution line after the power transmission and distribution line between the receiving point and the transmitting point is disconnected.
Preferably, the signaling unit is specifically configured to:
and injecting a monitoring signal with a frequency different from the self electric energy frequency of the power transmission and distribution line by using at least one position of at least one phase line of the power transmission and distribution line as a transmitting point.
Preferably, the signaling unit is further configured to:
and after injecting a monitoring signal into at least one position of at least one phase line of the power transmission and distribution line as a transmitting point, carrying out impedance matching on the monitoring signal, and enhancing the transmission power of the monitoring signal.
Preferably, the receiving unit is further configured to:
and before the preset position corresponding to the transmitting point in the power transmission and distribution line is used as a receiving point to receive the monitoring signal, filtering the monitoring signal, and filtering the power frequency quantity and harmonic signals of the power transmission and distribution line.
Preferably, the protection unit is specifically configured to:
and after the power transmission and distribution line between the receiving point and the transmitting point is broken, the circuit breakers at all ends of the power transmission and distribution line are disconnected in a delayed way.
The method and the system for protecting the power transmission and distribution line from the disconnection provided by the embodiment of the invention inject a monitoring signal into at least one position of at least one phase line of the power transmission and distribution line as a transmitting point; receiving the monitoring signal by taking a preset position corresponding to the transmitting point in the power transmission and distribution line as a receiving point; when the receiving point does not receive the monitoring signal and the main protection of the power transmission and distribution line is not operated, determining that the power transmission and distribution line between the receiving point and the transmitting point is broken; starting the disconnection protection of the power transmission and distribution line after the power transmission and distribution line between the receiving point and the transmitting point is disconnected; therefore, the embodiment of the invention injects the monitoring signal independent of the power transmission and distribution line on the power transmission and distribution line, determines the line break fault of the line by whether the monitoring signal can be received and whether the main protection of the line acts, and starts the corresponding line break protection, thereby being not influenced by the operation mode of the power system and the structure of the power grid, being applicable to various load conditions and having wider application range.
Drawings
Fig. 1 is a schematic flow chart of a power transmission and distribution line disconnection protection method according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a second power transmission and distribution line disconnection protection system according to an embodiment of the present invention;
fig. 3 is a schematic flow chart of a method for protecting a power transmission line between three substations according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of a disconnection protection system of a power transmission line between three substations according to an embodiment of the present invention.
Detailed Description
So that the manner in which the features and aspects of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings.
Example one
Fig. 1 is a schematic flow chart of a power transmission and distribution line disconnection protection method according to an embodiment of the present invention, in an embodiment of the present invention, a main body that needs to protect the power transmission and distribution line disconnection may be a power transmission and distribution line protection control device, and the method may be implemented by the power transmission and distribution line protection control device, which is referred to as a protection control device for short, as shown in fig. 1, and the method includes:
step 101: injecting a monitoring signal into at least one position of at least one phase line of the power transmission and distribution line as a transmitting point;
here, the monitoring signal is independent of the power transmission and distribution line, so that the monitoring signal is not influenced by the operation mode of the power system and the structure of the power grid, and the monitoring is more accurate.
In the embodiment of the invention, a monitoring signal can be injected into one phase line, and the on-off of one phase line is only monitored; or injecting different monitoring signals into each phase circuit respectively to monitor the on-off of each phase circuit respectively.
The monitoring signal may include an electrical signal and a sonic signal; the electric signal refers to voltage or current which changes along with time, so that the electric signal can be represented as a function of time in mathematical description and the waveform of the electric signal can be drawn; the propagation speed of the acoustic wave signal in the solid far exceeds that in the air, generally, the propagation speed of the acoustic wave signal in pure copper can reach 3750 m/s, and the propagation speed of the acoustic wave signal in the air is only 340 m/s, so that the disconnection condition of the power transmission and distribution line can be determined by injecting the acoustic wave signal into the power transmission and distribution line;
theoretically, a monitoring signal of any frequency can be used as the monitoring signal in the embodiment of the present invention, but in order to avoid interference of the power transmission and distribution line, the control and protection device generally selects a monitoring signal of a frequency different from the power frequency of the power transmission and distribution line, and the frequency of the signal cannot be the same as the frequency of a harmonic that jeopardizes the power quality;
preferably, the frequency of the electrical signal can be selected from the range of 300 to 20000Hz, the frequency range is simple to implement, and the propagation distance is long; the sound wave signal can be an ultrasonic wave signal, and the preferred frequency range can be 20000Hz to 60000 Hz;
in practical use, an electric signal is generally selected as a monitoring signal; compared with the sound wave signal, the electric signal is easier to implement and more widely used.
Further, in order to identify the disconnection fault in time, a monitoring signal can be continuously injected into the signaling point.
Furthermore, after injecting the monitoring signal into at least one position of at least one phase line of the power transmission and distribution line as a signaling point, the method further comprises:
and carrying out impedance matching on the monitoring signal, and enhancing the transmission power of the monitoring signal.
In the embodiment of the present invention, the transmission point may be an end point of a phase line, that is, a line at a substation;
in actual use, a transmitting device can be installed in a substation machine room near a transmitting point, and an injection port of the transmitting device is connected to the transmitting point in a communication mode; the control and protection device controls the transmitting device.
Step 102: receiving the monitoring signal by taking a preset position corresponding to the transmitting point in the power transmission and distribution line as a receiving point;
the control and protection device can set one or more receiving points to receive the monitoring signals at a preset position corresponding to the transmitting point in the power transmission and distribution line;
specifically, the control and protection device may preset a distance standard when setting the receiving point, that is, the distance between the receiving point and the transmitting point is within a preset range.
Further, before receiving the monitoring signal by using a preset position corresponding to the transmitting point in the power transmission and distribution line as a receiving point, the method further includes:
filtering the monitoring signal, and filtering out the power frequency quantity and harmonic signals of the power transmission and distribution line; the power frequency quantity of the power transmission and distribution line is an electric energy signal which needs to be transmitted or distributed by the power transmission and distribution line, and if the power frequency quantity is not filtered, the power frequency quantity not only interferes with a monitoring signal, but also damages a receiving device.
In the embodiment of the invention, the receiving point is the same as the transmitting point, and can be an end point of a line of one phase, namely a line at a transformer substation;
in practical use, the signal receiving device can be installed in a substation machine room near a signal receiving point, and a receiving port of the signal receiving device is connected to the signal receiving point in a communication mode; the control and protection device controls the receiving device.
Step 103: when the receiving point does not receive the monitoring signal and the main protection of the power transmission and distribution line is not operated, determining that the power transmission and distribution line between the receiving point and the transmitting point is broken;
here, the main protection generally refers to a control protection device which can quickly respond to a fault at any point on the power transmission and distribution line and can quickly cut off the line; for a high-voltage transmission line, the main protection can be line pilot protection, and according to the protection principle, the main protection can also be divided into pilot direction, pilot distance, pilot differential protection and current phase differential protection; the main protection is generally communicated with a control protection device, and the control protection device can acquire the action condition of the main protection in real time.
When the receiving point receives the monitoring signal within the preset time, the control and protection device can determine the line communication between the receiving point and the transmitting point; however, in order to more reliably determine the occurrence of the disconnection of the power transmission and distribution line between the receiving point and the transmitting point, a plurality of conditions, specifically:
when the receiving point does not receive the monitoring signal within the preset time, and the receiving point and the transmitting point are positioned on the same phase line, and the distance between the receiving point and the transmitting point is within the preset range, the control and protection device can preliminarily determine that the line between the receiving point and the transmitting point is broken;
the time range from the injection of the monitoring signal to the reception of the monitoring signal is specified to avoid the time delay caused by the interference of other signals or special disconnection, because the speed of the monitoring signal is very fast, if the monitoring signal adopts an electric signal, the speed is similar to the speed of light; if the monitoring signal is a sound wave signal, the speed is very high and far exceeds the sound speed in the air, and if the corresponding monitoring signal cannot be received in a short time, the monitoring signal can be considered as not received;
the distance range between the receiving point and the transmitting point is defined in consideration of large attenuation in propagation regardless of an electric signal or an acoustic signal, and in order to avoid erroneous judgment, the distance range between the receiving point and the transmitting point needs to be defined.
On the basis of preliminarily determining that the line between the receiving point and the transmitting point is broken, whether the main protection of the power transmission and distribution line acts or not is determined; if the main protection of the power transmission and distribution line is not acted, the line between the receiving point and the transmitting point can be more reliably determined to be broken;
because the action of the main protection requires the communication and electrical quantity signals of the power transmission and distribution line, if the line is broken under light load and is not converted into a ground fault, the main protection cannot act.
Step 104: and starting the disconnection protection of the power transmission and distribution line after the power transmission and distribution line between the receiving point and the transmitting point is disconnected.
Specifically, after the power transmission and distribution line between the receiving point and the transmitting point is broken, the control and protection device delays to disconnect the circuit breakers at each end of the power transmission and distribution line;
in particular, the opening of the circuit breaker by the control and protection device is performed by protecting a trip outlet.
The power transmission and distribution line between the receiving point and the transmitting point is broken, the broken line can fall to the ground or other places, voltage can still exist on the fallen line, and great potential safety hazard exists, so that the control and protection device disconnects the circuit breakers at all ends of the power transmission and distribution line.
The disconnection protection requires that each end of the circuit is configured, and the control protection device needs to send a joint tripping signal to other disconnection protection except the local end to realize the disconnection of the circuit breaker at each end; the control and protection devices at all ends are communicated with each other.
The purpose of the delay setting when the control protection device disconnects the circuit breakers at all ends of the power transmission and distribution line is to ensure the reliable judgment of the disconnection when the main protection does not act.
Specifically, the time of the delay may be set to 0.1S to 0.4S.
Example two
Fig. 2 is a schematic structural diagram of a broken line protection system of a power transmission and distribution line according to an embodiment of the present invention, and as shown in fig. 2, the system includes a transmitting unit 31, a receiving unit 32, and a protection unit 33; wherein,
the transmitting unit 31 is configured to inject a monitoring signal into at least one position of at least one phase line of the power transmission and distribution line as a transmitting point;
the receiving unit 32 is configured to receive the monitoring signal and determine on/off of a power transmission and distribution line between the receiving point and the transmitting point;
and the protection unit 33 is configured to start the disconnection protection of the power transmission and distribution line after the power transmission and distribution line between the receiving point and the transmitting point is disconnected.
For clarity of description, the following will respectively describe each module in detail:
the transmitting unit 31 is configured to inject a monitoring signal into at least one position of at least one phase line of the power transmission and distribution line as a transmitting point;
the monitoring signal is independent of the power transmission and distribution line, so that the monitoring signal is not influenced by the operation mode of a power system and the structure of a power grid, and the monitoring is more accurate;
in the embodiment of the invention, monitoring signals can be injected into one phase line to monitor the on-off of one phase line, or different monitoring signals can be injected into each phase line to monitor the on-off of each phase line.
The monitoring signal may include an electrical signal and a sonic signal; the electric signal refers to voltage or current which changes along with time, so that the electric signal can be represented as a function of time in mathematical description and the waveform of the electric signal can be drawn; the propagation speed of the sound wave signal in the solid is far from that of the ultrasonic wave in the air, generally, the propagation speed of the sound wave signal in pure copper can reach 3750 m/s, and the propagation speed of the sound wave signal in the air is only 340 m/s, so that the disconnection condition of the power transmission and distribution line can be determined by injecting the sound wave signal into the power transmission and distribution line;
in theory, any frequency of monitoring signal can be used as the monitoring signal in the embodiment of the present invention, but in order to avoid interference of power in the power transmission and distribution line, the transmitting unit 31 generally selects a monitoring signal with a frequency different from the power frequency of the power transmission and distribution line itself, and the frequency of the monitoring signal cannot be the same as the frequency of the harmonic that jeopardizes power quality;
preferably, the frequency of the electrical signal can be selected from the range of 300 to 20000Hz, the frequency range is simple to implement, and the propagation distance is long; the sound wave signal can be an ultrasonic wave signal, and the preferred frequency range can be 20000Hz to 60000 Hz;
in practical use, an electric signal is generally selected as a monitoring signal; compared with the sound wave signal, the electric signal is easier to implement and more widely used.
Further, in order to identify the disconnection fault in time, a monitoring signal can be continuously injected into the signaling point.
Furthermore, after injecting the monitoring signal into at least one position of at least one phase line of the power transmission and distribution line as a signaling point, the signaling unit 31 is further configured to:
and carrying out impedance matching on the monitoring signal, and enhancing the transmission power of the monitoring signal.
The receiving unit 32 is configured to receive the monitoring signal and determine on/off of a power transmission and distribution line between the receiving point and the transmitting point;
the receiving unit 32 may set one or more receiving points at a preset position corresponding to the transmitting point in the power transmission and distribution line to receive the monitoring signal;
specifically, the receiving unit 32 may preset a distance criterion when a receiving point is set, that is, the distance between the receiving point and the transmitting point is within a preset range.
Further, before receiving the monitoring signal by using a preset position corresponding to the transmitting point in the power transmission and distribution line as a receiving point, the receiving unit 32 is further configured to:
and filtering the monitoring signal, and filtering the power frequency quantity and harmonic signals of the power transmission and distribution line. The power frequency quantity of the power transmission and distribution line is an electric energy signal which needs to be transmitted or distributed by the power transmission and distribution line, and the power frequency quantity is not filtered, so that the monitoring signal is interfered, and the receiving unit 32 is damaged.
When the receiving point receives the monitoring signal within a preset time, the receiving unit 32 may determine that the line between the receiving point and the sending point is connected; however, in order to more reliably determine that the power transmission and distribution line between the receiving point and the transmitting point is broken, a plurality of conditions, specifically:
when the receiving point does not receive the monitoring signal within a preset time, and the receiving point and the transmitting point are located on the same phase line, and the distance between the receiving point and the transmitting point is within a preset range, the receiving unit 32 may preliminarily determine that the line between the receiving point and the transmitting point is broken;
the time range from the injection of the monitoring signal to the reception of the monitoring signal is specified to avoid the time delay caused by the interference of other signals or special disconnection, because the speed of the monitoring signal is very fast, if the monitoring signal adopts an electric signal, the speed is similar to the speed of light; if the monitoring signal is a sound wave signal, the speed is very high and far exceeds the sound speed in the air, and if the corresponding monitoring signal cannot be received in a short time, the monitoring signal can be considered as not received;
the distance range between the receiving point and the transmitting point is defined in consideration of large attenuation in propagation regardless of an electric signal or an acoustic signal, and in order to avoid erroneous judgment, the distance range between the receiving point and the transmitting point needs to be defined.
On the basis of preliminarily determining that the line between the receiving point and the transmitting point is broken, whether the main protection of the power transmission and distribution line acts or not is determined; if the main protection of the power transmission and distribution line is not acted, the line between the receiving point and the transmitting point can be more reliably determined to be broken;
because the action of the main protection requires the communication and electrical quantity signals of the power transmission and distribution line, if the line is broken under light load and is not converted into a ground fault, the main protection cannot act.
And the protection unit 33 is configured to start the disconnection protection of the power transmission and distribution line after the power transmission and distribution line between the receiving point and the transmitting point is disconnected.
Specifically, after the power transmission and distribution line between the receiving point and the transmitting point is disconnected by the protection unit 33, the protection unit 33 delays to disconnect the circuit breakers at each end of the power transmission and distribution line;
in particular, the opening of the circuit breaker by the protection unit 33 is performed by protecting the trip outlet.
The power transmission and distribution line between the receiving point and the transmitting point is broken, the broken line may fall to the ground or other places, and the dropped line may have voltage thereon, which has a great safety hazard, so that the protection unit 33 disconnects the circuit breakers at each end of the power transmission and distribution line.
The disconnection protection requires that each end of the circuit is configured, and the control protection device needs to send a joint tripping signal to other disconnection protection except the local end to realize the disconnection of the circuit breaker at each end; the control and protection devices at all ends are communicated with each other.
The purpose of the delay setting when the control protection device disconnects the circuit breakers at all ends of the power transmission and distribution line is to ensure the reliable judgment of the disconnection when the main protection does not act.
Specifically, the time of the delay may be set to 0.1S to 0.4S.
EXAMPLE III
The embodiment of the invention relates to a disconnection protection method for a power transmission line between transformer substations, wherein a line is the power transmission line between two transformer substations, the frequency of the electric energy of the power transmission line is power frequency, namely the domestic frequency is generally 50 Hz; the monitoring signal is a high-frequency electric signal, and specifically, the frequency of the monitoring signal is 3000-20000 Hz.
Fig. 3 is a schematic flow chart of a method for protecting a power transmission line between three substations according to an embodiment of the present invention, and as shown in fig. 3, the method includes:
step 201: injecting a monitoring signal into a first substation;
specifically, the monitoring signal is a high-frequency electrical signal, and the frequency of the electrical signal cannot be the same as the frequency of a harmonic which jeopardizes the quality of the electric energy;
the monitoring signal is injected into the power transmission line through a transceiver, and the transceiver is controlled by a power transmission line control and protection device;
in order to identify the disconnection fault in time, a monitoring signal can be injected into the power transmission line uninterruptedly;
furthermore, the impedance matching can be carried out on the monitoring signal, and the transmission power of the monitoring signal is enhanced.
Step 202: receiving a monitoring signal at a second substation;
when the monitoring signal is received, continuing to execute the step;
when the monitoring signal is not received and the receiving point and the transmitting point are located on the same phase line, step 203 is entered.
Step 203: confirming whether the main protection acts;
when the main protection of the power transmission line does not act, determining that the power transmission line between the first transformer substation and the second transformer substation is broken, and entering step 204;
and when the main protection action of the power transmission line is performed, ending the process.
Step 204: and starting the disconnection protection of the power transmission line.
Specifically, the control and protection device disconnects the circuit breakers at the two ends of the transmission line between the first substation and the second substation.
Example four
The embodiment of the invention relates to a disconnection protection system for a power transmission line between transformer substations, wherein a line is the power transmission line between two transformer substations, the frequency of the electric energy of the power transmission line is power frequency, namely the domestic frequency is generally 50 Hz; the monitoring signal is a high-frequency electric signal, and specifically, the frequency of the monitoring signal is 3000-20000 Hz.
Fig. 4 is a schematic structural diagram of a disconnection protection system of a power transmission line between three substations according to an embodiment of the present invention, and as shown in fig. 4, the disconnection protection system of the power transmission line includes a power transmission line 51, a wave trap 52, a coupling capacitor 53, a combination filter 54, a high-frequency cable 55, a transceiver 56, and a disconnection protection device 57; wherein,
the power transmission line 51 is a power transmission line between two transformer substations, is a line which needs to be judged whether to be disconnected in use, and is also used for transmitting monitoring signals;
the wave trap 52 is used for limiting the propagation of the monitoring signal outside the power transmission line 51, ensuring the signal strength and avoiding the interference to other lines; the wave trap can be an LC parallel resonance circuit, the LC parallel resonance circuit can generate great impedance for high-frequency monitoring signals, and only has small impedance for electric energy in the relatively low-frequency electric transmission line 51, so that the transmission of the electric energy in the electric transmission line 51 can not be influenced;
the coupling capacitor 53 is used for preventing the electric energy of the power transmission line 51 from entering the transceiver and avoiding the damage of the transceiver; the coupling capacitor 53 generates a large impedance for the power in the relatively low frequency power transmission line 51, and has a small impedance for the high frequency monitoring signal, so that the transmission of the monitoring signal is not affected.
The combination filter 54 is used for enhancing the power of the monitoring signal; the combined filter 54 comprises a filter capacitor and an impedance matching capacitor, and the filter capacitor is matched with the coupling capacitor 53 and used for preventing the power frequency quantity and the harmonic signals in the power transmission line 51 from entering the transceiver; the impedance matching capacitor is used for matching the impedance generated by the monitoring signal, playing a role of impedance matching and enhancing the power of the monitoring signal;
specifically, when the transceiver 56 is used for signaling, the combining filter 54 filters and then impedance matches; when the transceiver 56 is used for receiving, the combined filter 54 performs impedance matching and then filtering;
further, for safety reasons, the combined filter 54 is grounded through a grounding switch.
The high-frequency cable 55 is used for transmitting a high-frequency monitoring signal, and is a component in the prior art and is not described in detail;
the transceiver 56 is used for injecting or receiving monitoring signals and determining whether the power transmission line 51 between the transformer substations is broken;
specifically, when the near-end transceiver 56 does not receive the monitoring signal injected by the far-end transceiver 56 within a preset time and the main protection of the near-end is not activated, it is determined that the power transmission line 51 between the near-end transceiver 56 and the far-end transceiver 56 is disconnected; similarly, when the far-end transceiver 56 does not receive the monitoring signal injected by the near-end transceiver 56 within the preset time and the far-end main protection does not act, it is determined that the power transmission line 51 between the far-end transceiver 56 and the near-end transceiver 56 is disconnected;
the transceiver 56 is a high-frequency transceiver, has the functions of transmitting and receiving signals, is generally installed in a machine room of a transformer substation, and transmits a high-frequency monitoring signal through the high-frequency cable 55;
typically, the transceiver 56 communicates with a transmission line control and protection device of a substation room.
And the disconnection protection device 57 is configured to instruct the circuit breakers at two ends of the power transmission line 51 to disconnect the power transmission line 51 after the power transmission and distribution line between the receiving point and the transmitting point is disconnected.
The above description is only exemplary of the present invention and should not be taken as limiting the scope of the present invention, and any modifications, equivalents, improvements, etc. that are within the spirit and principle of the present invention should be included in the present invention.
Claims (8)
1. A power transmission and distribution line disconnection protection method is characterized by comprising the following steps:
injecting a monitoring signal into at least one position of at least one phase line of the power transmission and distribution line as a transmitting point;
receiving the monitoring signal by taking a preset position corresponding to the transmitting point in the power transmission and distribution line as a receiving point;
when the receiving point does not receive the monitoring signal and the main protection of the power transmission and distribution line is not operated, determining that the power transmission and distribution line between the receiving point and the transmitting point is broken;
and after the power transmission and distribution line between the receiving point and the transmitting point is broken, the circuit breakers at all ends of the power transmission and distribution line are disconnected in a delayed way.
2. The method of claim 1, wherein injecting the monitoring signal into at least one location of at least one phase of the power transmission and distribution line as a signaling point comprises:
and injecting a monitoring signal with a frequency different from the self electric energy frequency of the power transmission and distribution line by using at least one position of at least one phase line of the power transmission and distribution line as a transmitting point.
3. The method of claim 1 or 2, wherein after injecting the monitoring signal as the signaling point into at least one of the at least one phase of the transmission and distribution line, the method further comprises:
and carrying out impedance matching on the monitoring signal, and enhancing the transmission power of the monitoring signal.
4. The method according to claim 1 or 2, wherein before receiving the monitoring signal by using a preset location corresponding to the transmitting point in the power transmission and distribution line as a receiving point, the method further comprises:
and filtering the monitoring signal, and filtering the power frequency quantity and harmonic signals of the power transmission and distribution line.
5. The power transmission and distribution line disconnection protection system is characterized by comprising a transmitting unit, a receiving unit and a protection unit; wherein,
the transmitting unit is used for injecting monitoring signals into at least one position of at least one phase line of the power transmission and distribution line as a transmitting point;
the receiving unit is used for receiving the monitoring signal and determining the connection and disconnection of the power transmission and distribution line between the receiving point and the transmitting point;
and the protection unit is used for disconnecting the circuit breakers at all ends of the power transmission and distribution line after the power transmission and distribution line between the receiving point and the transmitting point is broken.
6. The system according to claim 5, wherein said signaling unit is specifically configured to:
and injecting a monitoring signal with a frequency different from the self electric energy frequency of the power transmission and distribution line by using at least one position of at least one phase line of the power transmission and distribution line as a transmitting point.
7. The system according to claim 5 or 6, wherein the signaling unit is further configured to:
and after injecting a monitoring signal into at least one position of at least one phase line of the power transmission and distribution line as a transmitting point, carrying out impedance matching on the monitoring signal, and enhancing the transmission power of the monitoring signal.
8. The system of claim 5 or 6, wherein the receiving unit is further configured to:
and before the preset position corresponding to the transmitting point in the power transmission and distribution line is taken as a receiving point to receive the monitoring signal, filtering the monitoring signal, and filtering the power frequency quantity and harmonic signals of the power transmission and distribution line.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710172797.7A CN107069678B (en) | 2017-03-22 | 2017-03-22 | A kind of electric line thread-breakage protecting and system |
| PCT/CN2017/113063 WO2018171240A1 (en) | 2017-03-22 | 2017-11-27 | Method and system for protection against disconnection of power transmission and distribution lines |
| KR1020197023912A KR102287695B1 (en) | 2017-03-22 | 2017-11-27 | Method and system for protection against disconnection of transmission and distribution lines |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201710172797.7A CN107069678B (en) | 2017-03-22 | 2017-03-22 | A kind of electric line thread-breakage protecting and system |
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| CN107069678A CN107069678A (en) | 2017-08-18 |
| CN107069678B true CN107069678B (en) | 2019-06-21 |
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| CN201710172797.7A Active CN107069678B (en) | 2017-03-22 | 2017-03-22 | A kind of electric line thread-breakage protecting and system |
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| Country | Link |
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| KR (1) | KR102287695B1 (en) |
| CN (1) | CN107069678B (en) |
| WO (1) | WO2018171240A1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107069678B (en) * | 2017-03-22 | 2019-06-21 | 南京南瑞继保电气有限公司 | A kind of electric line thread-breakage protecting and system |
| CN109256756B (en) * | 2018-10-23 | 2019-08-23 | 西安交通大学 | The MMC-HVDC to power to passive network exchanges adaptive reclosing method |
| CN109557419B (en) * | 2018-12-13 | 2020-11-06 | 国网山西省电力公司大同供电公司 | A kind of transmission line detection method |
| CN110676826B (en) * | 2019-11-28 | 2021-03-23 | 国网江苏省电力有限公司镇江供电分公司 | Line disconnection protection method for comparing vector difference of voltages at two sides of line and application |
| CN112596018B (en) | 2020-12-09 | 2021-09-17 | 南方电网电力科技股份有限公司 | High-frequency signal-based power consumer relative position identification device, method and equipment |
| CN113655338B (en) * | 2021-08-16 | 2023-03-03 | 广东电网有限责任公司 | Positioning device for tripping point of power transmission line |
| CN114640093B (en) * | 2022-02-23 | 2023-03-24 | 北京天能继保电力科技有限公司 | Method and device for protecting broken line of distributed power transmission and distribution line |
| CN116577699A (en) * | 2023-07-13 | 2023-08-11 | 三峡集团浙江能源投资有限公司 | Loss-of-ground monitoring device for small-resistance grounding system of pumped storage power station |
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Also Published As
| Publication number | Publication date |
|---|---|
| KR20190102081A (en) | 2019-09-02 |
| CN107069678A (en) | 2017-08-18 |
| WO2018171240A1 (en) | 2018-09-27 |
| KR102287695B1 (en) | 2021-08-06 |
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