CN112821364A - Protection system and method for mixed connection line with reactor - Google Patents

Protection system and method for mixed connection line with reactor Download PDF

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Publication number
CN112821364A
CN112821364A CN202110197696.1A CN202110197696A CN112821364A CN 112821364 A CN112821364 A CN 112821364A CN 202110197696 A CN202110197696 A CN 202110197696A CN 112821364 A CN112821364 A CN 112821364A
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China
Prior art keywords
line
group
protection
reactor
fault
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CN202110197696.1A
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Inventor
祝磊
陈一悰
左宝峰
胡建利
陈洁羽
万青
谈浩
徐晓春
李奔
王玉龙
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State Grid Corp of China SGCC
NR Engineering Co Ltd
Electric Power Research Institute of State Grid Shaanxi Electric Power Co Ltd
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State Grid Corp of China SGCC
NR Engineering Co Ltd
Electric Power Research Institute of State Grid Shaanxi Electric Power Co Ltd
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Priority to CN202110197696.1A priority Critical patent/CN112821364A/en
Publication of CN112821364A publication Critical patent/CN112821364A/en
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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
    • 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
    • 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
    • H02H7/263—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 measured values

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  • General Physics & Mathematics (AREA)
  • Emergency Protection Circuit Devices (AREA)

Abstract

The invention discloses a protection system and a method for a mixed connection line with an electric reactor, wherein the method comprises the following steps: the on-site transmission module is added at the joint of the overhead line and the cable, collects the power frequency quantity at the joint of the hybrid line and communicates with the line protection modules at two ends and the reactor protection module, so that sampling synchronization and important data interaction at each side are realized; through the fault interval judgment of the mixed connection line system with the reactor, effective closed-weight signals are provided to avoid overlapping permanent faults, and long-jump signals are economically transmitted to the line protection modules on two sides, so that the faults of the reactor are quickly isolated, and the mixed connection line system is protected. The invention can improve the operation reliability of the mixed connection line.

Description

Protection system and method for mixed connection line with reactor
Technical Field
The invention belongs to the technical field of power system relay protection, and particularly relates to a protection system and a method for a mixed connection circuit with an electric reactor.
Background
With the rapid development of modern urbanization construction, available land resources are increasingly tense; however, the criss-cross overhead lines occupy a large amount of available space, which is one of the factors hindering the urbanization construction, and the replacement of the overhead line network power supply by the cable network power supply is a necessary trend of the modern urbanization construction. Compared with the overhead line, the cable has the advantages of high transmission capacity and reliability, low application cost, space saving, city appearance beautification and the like, is widely applied, and is gradually developed into the power supply of the cable-overhead line hybrid line on the basis of the power supply of the original overhead line network; meanwhile, the economic influence of the operation of the cable is considered, and the operation scene of the parallel reactor at the middle section of the mixed connection line appears. This operational scenario presents the following problems for protection configuration:
1) reclosing of the hybrid line is difficult to realize. Because the cable fault is a permanent fault, in order to avoid secondary impact caused by superposition fault, it is a common practice in China that when the cable occupation ratio exceeds a certain proportion (different from place to place) of the whole line, the reclosing of a mixed connection line is not put into use. Therefore, when the mixed connection line has transient faults, the line cannot be superposed after being tripped, and the power supply reliability is influenced;
2) the trip protection scheme of the middle-section reactor needs to be researched. Generally, a reactor is connected with a line through an isolating switch and is installed on one side or two sides of the line, the reactor protects a local circuit breaker of the line which is tripped firstly, and the circuit breaker on the opposite side of the line is tripped through remote transmission of starting line protection, and fault criteria on the opposite side of the line need to be met. However, the parallel reactor at the middle section of the mixed connection line lacks an on-site circuit breaker, and the circuit breakers at the two sides of the line need to be tripped after the protection action of the reactor; and when the middle-section shunt reactor has a fault, under the condition that the circuit breakers on the two sides of the circuit are not tripped, the fault criteria on the two sides of the circuit are difficult to meet, so that the circuit breakers on the two sides of the circuit are difficult to trip through remote transmission.
In summary, no protection configuration and solution related to the parallel reactor at the middle section of the mixed connection line exists at present.
Disclosure of Invention
The present invention is directed to a protection system and method for a hybrid circuit with reactors, which solves one or more of the above problems. The invention can provide protection for the mixed connection line system and can improve the operation reliability of the mixed connection line.
In order to achieve the purpose, the invention adopts the following technical scheme:
the invention relates to a protection system for a mixed connection line with an electric reactor, which comprises: the system comprises a first group of mutual inductors, a second group of mutual inductors, a third group of mutual inductors, a fourth group of mutual inductors, a first group of line protection modules, a second group of line protection modules, an on-site transmission module and a reactor protection module;
the first group of transformers and the first group of line protection modules are arranged at one end of the mixed connection line, and the first group of transformers are connected with the input end of the first group of line protection modules;
the second group of mutual inductors, the third group of mutual inductors, the in-situ transmission module and the reactor protection module are used for being arranged at the connecting part of an overhead line and a cable in a mixed connection circuit with an electric reactor, the second group of mutual inductors are connected with the input end of the in-situ transmission module, the third group of mutual inductors are connected with the input end of the reactor protection module, and the in-situ transmission module is respectively connected with the first group of circuit protection module, the second group of circuit protection module and the reactor protection module;
and the fourth group of mutual inductors and the second group of line protection modules are used for being arranged at the other end of the mixed connection line, and the fourth group of mutual inductors are connected with the input end of the second group of line protection modules.
The invention is further improved in that the first group of mutual inductors, the second group of mutual inductors and the fourth group of mutual inductors respectively comprise current transformers and voltage transformers; the third group of transformers comprises only current transformers.
The invention has the further improvement that the local transmission module is directly connected with the first group of line protection modules and the second group of line protection modules through optical fiber channels or connected through multiplexing channels; the on-site transmission module is directly connected with the reactor protection module through a cable.
In a further improvement of the present invention, the line protection module or the reactor protection module specifically includes:
the acquisition unit is used for sampling the power frequency quantity of the electric quantity at the side;
the receiving unit is used for receiving the power frequency quantity sampling of the local transmission module and the trip signals and the calculated quantity of other side protection modules;
the transmitting unit is used for transmitting the local side power frequency quantity sampling and tripping signal;
the synchronous processing unit is used for synchronously processing the sampling data of the acquisition unit and the receiving data of the receiving unit by adopting a sampling value time adjustment method based on a data channel;
the fault and fault interval judging unit is used for judging faults according to current power frequency quantities at two ends of the hybrid circuit or at two ends of the reactor; and (4) carrying out fault interval judgment according to the comprehensive judgment result, and finally determining whether to send tripping and closing signals.
The invention is further improved in that the first group of line protection modules, the second group of line protection modules and the local transmission module all comprise photoelectric conversion modules for converting, receiving and transmitting optical signals.
The invention discloses a protection method for a mixed connection line with an electric reactor, which is characterized in that the protection system based on the invention comprises the following steps:
step (1), analog quantity sampling comprises the following steps: respectively sampling the power frequency quantity of the electric quantity of the current side through a first group of circuit protection modules, a second group of circuit protection modules, a local transmission module and a reactor protection module to obtain four-side sampling data;
step (2), synchronizing the four-side sampling data to obtain data after synchronous processing;
and (3) starting criterion calculation based on the data after synchronous processing, wherein the criterion calculation comprises the following steps: the first group of line protection modules, the second group of line protection modules and the reactor protection module are used for calculating starting criteria; when the starting criterion of the line protection module is met or the starting criterion of the reactor protection module is met, the step (4) is carried out, otherwise, the step (1) is returned;
and (4) judging the fault and the fault section, comprising the following steps: when the circuit protection module is started, the first group of circuit protection modules and the second group of circuit protection modules respectively judge the internal and external faults according to the current power frequency quantity at two ends of the mixed connection circuit, and when the reactor protection module is started, the reactor protection module judges the internal and external faults according to the current power frequency quantity of the second group of mutual inductors and the third group of mutual inductors; when the occurrence of the intra-area fault is judged, the first group of line protection modules and the second group of line protection modules judge the fault section;
and (5) outputting tripping and closing signals, wherein the tripping and closing signals comprise: when the fault is judged to occur in the mixed connection line cable line section, a tripping signal and a closing signal are sent out; when the fault is judged to occur in the overhead line section of the hybrid line, only a trip signal is sent out; when the fault is judged to occur in the reactor section, tripping and closing signals are sent to the on-site transmission module, the signals are sent to the line protection modules at two ends of the mixed connection line through the on-site transmission module, and the line protection modules trip out the circuit breakers at two sides through judgment.
The invention is further improved in that the step (2) comprises the following specific steps: the local transmission module is used as a host, the first group of line protection modules and the second group of line protection modules are used as slaves, and the slaves perform sampling synchronization with the host by adopting a sampling value time adjustment method based on a data channel.
The further improvement of the present invention is that, in the step (4), the fault judgment of the line protection module specifically includes: calculating whether differential current and braking current meet criterion or not by using formula (1) according to current power frequency quantities at two ends of the hybrid circuit, and exchanging the criterion result with the opposite side; when both sides are not satisfied, judging as an out-of-area fault; when both sides meet the criterion, judging the fault as an intra-area fault;
Figure BDA0002947693210000041
in the formula ICDΦIs a differential current equal to the magnitude of the vector sum of the currents on both sides; i isRΦThe braking current is equal to the amplitude of the vector difference of the currents on the two sides; i isSETA constant value is enabled for the differential current.
The further improvement of the present invention is that, in the step (4), the specific step of performing the fault section judgment includes:
when the fault is judged to be an intra-area fault, calculating whether the voltage at the joint of the hybrid circuit and the voltage power frequency of the on-site acquisition module meets the criterion by using the formula (2), and exchanging the criterion result with the opposite side; when the calculation of the line protection module at one side meets the requirement of one side, judging that the fault occurs in the mixed connection line section where the line protection module which does not meet the requirement is located; when the calculation of the line protection modules at the two sides meets the criterion condition, the fault is judged to occur in the parallel reactor section of the mixed connection line;
Figure BDA0002947693210000042
in the formula (I), the compound is shown in the specification,
Figure BDA0002947693210000044
in order to calculate the voltage at the connection position of the hybrid line according to the voltage current of the fault phase of the line at one side and the line impedance,
Figure BDA0002947693210000043
for the voltage at the junction of the hybrid line, ∈SETIs a set voltage error range.
Compared with the prior art, the invention has the following beneficial effects:
in the system, the local transmission module collects the power frequency quantity at the joint of the hybrid circuit and communicates with the circuit protection modules at two ends and the reactor protection module, so that the fault interval judgment of the hybrid circuit system with the reactor is realized, the long jump signal is transmitted to the circuit protection modules at two sides, the protection is provided for the hybrid circuit system, the running reliability of the hybrid circuit can be effectively improved, and the system is economical and easy to realize engineering.
According to the method, the local transmission module is added at the joint of the overhead line and the cable, the local transmission module is used for collecting the power frequency quantity at the joint of the hybrid line and communicating with the line protection modules at two ends and the reactor protection module, so that the sampling synchronization at each side, the interaction of important data and the judgment of a fault interval are realized, the protection is provided for a hybrid line system, and the running reliability of the hybrid line is improved.
In conclusion, the protection system or method for the reactor in the middle section of the mixed connection line provided by the invention can realize complete protection of the mixed connection line and the reactor by accurately judging the fault section.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art are briefly introduced below; it is obvious that the drawings in the following description are some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.
Fig. 1 is a schematic diagram of a protection system for a hybrid line with reactors according to an embodiment of the present invention;
fig. 2 is a schematic flow chart of a protection method for a hybrid line with a reactor according to an embodiment of the present invention;
fig. 3 is a schematic diagram of the sampling synchronization in the embodiment of the present invention.
Detailed Description
In order to make the purpose, technical effect and technical solution of the embodiments of the present invention clearer, the following clearly and completely describes the technical solution of the embodiments of the present invention with reference to the drawings in the embodiments of the present invention; it is to be understood that the described embodiments are only some of the embodiments of the present invention. Other embodiments, which can be derived by one of ordinary skill in the art from the disclosed embodiments without inventive faculty, are intended to be within the scope of the invention.
Referring to fig. 1, a protection system for a hybrid circuit with reactors according to an embodiment of the present invention is a protection system for a reactor in a middle section of a hybrid circuit, including: the system comprises a first group of mutual inductors, a second group of mutual inductors, a third group of mutual inductors, a fourth group of mutual inductors, two groups of line protection modules, an on-site transmission module and a group of reactor protection modules; the first group of mutual inductors and the group of line protection modules are arranged at one end of a mixed connection line, the second group of mutual inductors, the third group of mutual inductors, the in-situ transmission module and the reactor protection module are arranged at the joint of an overhead line and a cable in the mixed connection line, the fourth group of mutual inductors and the other group of line protection module are arranged at the other end of the mixed connection line, the first group of mutual inductors and the fourth group of mutual inductors are respectively connected with the input ends of the line protection modules at two ends, the second group of mutual inductors are connected with the input end of the in-situ transmission module, the third group of mutual inductors are connected with the input end of the reactor protection module, the in-situ transmission module is respectively connected with the line protection modules at two sides, the in-situ transmission module comprises photoelectric conversion modules which are used for conversion and receiving and; meanwhile, the on-site transmission module is also directly connected with the reactor protection module through a cable. Specifically, the circuit breaker can be further included and used for receiving signals sent by the line protection module.
In the above embodiment, the line protection module and the reactor protection module include:
a collecting unit: sampling the power frequency quantity of the electric quantity of the local side;
a receiving unit: receiving power frequency quantity sampling of the local transmission module and trip signals and calculated quantities of other side protection modules;
a transmission unit: sending a local side power frequency quantity sampling and tripping signal;
a synchronization processing unit: synchronously processing the sampling data of the acquisition unit and the data of the receiving unit by adopting a sampling value time adjustment method based on a data channel;
a fault and fault section determination unit: and carrying out fault judgment according to the current power frequency quantity at two ends of the hybrid circuit or at two ends of the reactor, and carrying out fault interval judgment by the circuit protection module by integrating the judgment result to finally determine whether to send tripping and weight-off signals.
Referring to fig. 2, a protection method for a hybrid circuit with reactors according to an embodiment of the present invention is a protection method for a reactor in a middle section of a hybrid circuit, and specifically includes the following steps:
step (1), analog quantity sampling: the line protection module, the local transmission module and the reactor protection module at the two ends of the mixed connection line respectively sample the power frequency quantity of the electric quantity at the side;
step (2), four-side sampling synchronization: the local transmission module is used as a host to sample according to a fixed frequency, and the line protection modules at two ends and the reactor protection module are used as slaves to perform sampling synchronization with the host by adopting a sampling value time adjustment method based on a data channel;
referring to fig. 3, in the embodiment of the present invention, the local transmission module is used as a master, and the line protection modules at two ends and the reactor protection module are used as slaves to calculate the channel delay in real time by using a channel delay measurement technology based on the ping-pong principle; host at tm1Sending the current time mark of the host and the calculated channel delay t to the slave at any momentdA command of (2); delay t after slave receives commandmTime-to-slave current time scale and delay time tmReturning to the host; the time when the host receives the return information is tr2Calculating the channel delayComprises the following steps:
Figure BDA0002947693210000071
setting the internal clock of the host as the two-side clock, the host being at the current local time tmjWill include the channel delay tdSending a frame of information including an internal clock adjustment command to the slave, and enabling the slave to receive the information at the time tr3And tdFirst, t is determinedmjCorresponding to the time t of the sidesiThen, the clock deviation delta t in the master and the slave is calculatedc：
Δtc＝tsi-(tr3-td)＝tsi-tmj，
By adjusting the internal clock of the slave to Δ tcApproaching to zero, namely completing the real-time synchronization of the internal clocks of the modules at all sides;
and (3) starting criterion calculation: the circuit protection module and the reactor protection module perform starting criterion calculation; when the starting criterion of the line protection module is met or the starting criterion of the reactor protection module is met, the step (4) is carried out, otherwise, the step (1) is returned;
step (4), fault and fault section judgment: when the circuit protection module is started, the circuit protection module respectively judges the internal and external faults according to the current power frequency quantity at the two ends of the mixed connection circuit, and when the reactor protection module is started, the reactor protection module judges the internal and external faults according to the current power frequency quantity of the second group of mutual inductors and the third group of mutual inductors; when the protection module judges that an intra-area fault occurs, the line protection module judges a fault section;
for the two-side line protection modules, calculating whether differential current and braking current meet criteria or not by using a formula (1) according to current power frequency quantities at two ends of a mixed connection line, and exchanging the criteria results with the opposite side in real time; when both sides are not satisfied, judging as an out-of-area fault; when both sides meet the criterion, judging the fault as an intra-area fault;
Figure BDA0002947693210000081
in the formula ICDΦIs a differential current equal to the magnitude of the vector sum of the currents on both sides; i isRΦThe braking current is equal to the amplitude of the vector difference of the currents on the two sides; i isSETA constant value is enabled for the differential current.
When the line protection module and the reactor protection module judge that the faults exist in the area, the line protection module calculates whether the voltage at the joint of the hybrid line and the power frequency quantity of the voltage of the local acquisition module meet the criterion by using the formula (2) and exchanges the criterion result with the opposite side in real time; when the calculation of the line protection module at one side meets the requirement of one side, judging that the fault occurs in the mixed connection line section where the line protection module which does not meet the requirement is located; when the calculation of the line protection modules at the two sides meets the criterion condition, the fault is judged to occur in the parallel reactor section of the mixed connection line;
Figure BDA0002947693210000082
in the formula (I), the compound is shown in the specification,
Figure BDA0002947693210000083
in order to calculate the voltage at the connection position of the hybrid line according to the voltage current of the fault phase of the line at one side and the line impedance,
Figure BDA0002947693210000084
for the voltage, epsilon, collected at the junction of the hybrid lineSETIs a set voltage error range.
And (5) outputting tripping and closing signals: when the line protection module judges that a fault occurs in a mixed connection line cable line section, a tripping signal and a closing signal are sent out, and when the line protection module judges that the fault occurs in a mixed connection line overhead line section, only the tripping signal can be sent out; when the reactor protection module judges that a fault occurs in the reactor section, tripping and closing signals are sent to the on-site transmission module, the on-site transmission module sends the tripping and closing signals to the line protection modules at two ends of the mixed connection line, and the line protection modules trip out circuit breakers at two sides through judgment.
In summary, the invention discloses a protection system and a method for a reactor in the middle section of a hybrid line, which are characterized in that an in-situ transmission module is added at the joint of an overhead line and a cable, and the in-situ transmission module collects the power frequency quantity at the joint of the hybrid line and communicates with a line protection module and a reactor protection module at two ends, so that the sampling synchronization and important data interaction at each side are realized; by judging the fault section of the mixed connection line system with the reactor, an effective closed-weight signal is provided to avoid overlapping with a permanent fault, and a long-jump signal is economically transmitted to the line protection modules at two sides, so that the rapid isolation of the fault of the reactor is realized, and the protection of the mixed connection line system is realized; the invention can improve the operation reliability of the mixed connection line, and is economical and easy to realize engineering.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can make modifications and equivalents to the embodiments of the present invention without departing from the spirit and scope of the present invention, which is set forth in the claims of the present application.

Claims (9)

1. A protection system for a hybrid line with reactors, comprising: the system comprises a first group of mutual inductors, a second group of mutual inductors, a third group of mutual inductors, a fourth group of mutual inductors, a first group of line protection modules, a second group of line protection modules, an on-site transmission module and a reactor protection module;
the first group of transformers and the first group of line protection modules are arranged at one end of the mixed connection line, and the first group of transformers are connected with the input end of the first group of line protection modules;
the second group of mutual inductors, the third group of mutual inductors, the in-situ transmission module and the reactor protection module are used for being arranged at the connecting part of an overhead line and a cable in a mixed connection circuit with an electric reactor, the second group of mutual inductors are connected with the input end of the in-situ transmission module, the third group of mutual inductors are connected with the input end of the reactor protection module, and the in-situ transmission module is respectively connected with the first group of circuit protection module, the second group of circuit protection module and the reactor protection module;
and the fourth group of mutual inductors and the second group of line protection modules are used for being arranged at the other end of the mixed connection line, and the fourth group of mutual inductors are connected with the input end of the second group of line protection modules.
2. The protection system for the hybrid line with the reactor of claim 1, wherein the first group of transformers, the second group of transformers and the fourth group of transformers each comprise a current transformer and a voltage transformer; the third group of transformers comprises only current transformers.
3. The protection system for the hybrid line with reactor according to claim 1, wherein the in-situ transmission module is directly connected to the first group of line protection modules and the second group of line protection modules through fiber channels or connected through multiplexing channels; the on-site transmission module is directly connected with the reactor protection module through a cable.
4. The protection system for the hybrid line with the reactor according to claim 1, wherein the line protection module or the reactor protection module specifically comprises:
the acquisition unit is used for sampling the power frequency quantity of the electric quantity at the side;
the receiving unit is used for receiving the power frequency quantity sampling of the local transmission module and the trip signals and the calculated quantity of other side protection modules;
the transmitting unit is used for transmitting the local side power frequency quantity sampling and tripping signal;
the synchronous processing unit is used for synchronously processing the sampling data of the acquisition unit and the receiving data of the receiving unit by adopting a sampling value time adjustment method based on a data channel;
the fault and fault interval judging unit is used for judging faults according to current power frequency quantities at two ends of the hybrid circuit or at two ends of the reactor; and (4) carrying out fault interval judgment according to the comprehensive judgment result, and finally determining whether to send tripping and closing signals.
5. The protection system of claim 1, wherein the first group of line protection modules, the second group of line protection modules, and the in-situ transmission module each comprise an optical-to-electrical conversion module for converting and transceiving optical signals.
6. A protection method for a mixed connection line with a reactor, characterized in that, based on the protection system of claim 1, the method comprises the following steps:
step (1), analog quantity sampling comprises the following steps: respectively sampling the power frequency quantity of the electric quantity of the current side through a first group of circuit protection modules, a second group of circuit protection modules, a local transmission module and a reactor protection module to obtain four-side sampling data;
step (2), synchronizing the four-side sampling data to obtain data after synchronous processing;
and (3) starting criterion calculation based on the data after synchronous processing, wherein the criterion calculation comprises the following steps: the first group of line protection modules, the second group of line protection modules and the reactor protection module are used for calculating starting criteria; when the starting criterion of the line protection module is met or the starting criterion of the reactor protection module is met, the step (4) is carried out, otherwise, the step (1) is returned;
and (4) judging the fault and the fault section, comprising the following steps: when the circuit protection module is started, the first group of circuit protection modules and the second group of circuit protection modules respectively judge the internal and external faults according to the current power frequency quantity at two ends of the mixed connection circuit, and when the reactor protection module is started, the reactor protection module judges the internal and external faults according to the current power frequency quantity of the second group of mutual inductors and the third group of mutual inductors; when the occurrence of the intra-area fault is judged, the first group of line protection modules and the second group of line protection modules judge the fault section;
and (5) outputting tripping and closing signals, wherein the tripping and closing signals comprise: when the fault is judged to occur in the mixed connection line cable line section, a tripping signal and a closing signal are sent out; when the fault is judged to occur in the overhead line section of the hybrid line, only a trip signal is sent out; when the fault is judged to occur in the reactor section, tripping and closing signals are sent to the on-site transmission module, the signals are sent to the line protection modules at two ends of the mixed connection line through the on-site transmission module, and the line protection modules trip out the circuit breakers at two sides through judgment.
7. The protection method for the hybrid circuit with reactor according to claim 6, wherein the step (2) comprises the following steps: the local transmission module is used as a host, the first group of line protection modules and the second group of line protection modules are used as slaves, and the slaves perform sampling synchronization with the host by adopting a sampling value time adjustment method based on a data channel.
8. The protection method for the mixed-connection line with the reactor according to claim 6, wherein in the step (4), the fault judgment of the line protection module specifically comprises: calculating whether differential current and braking current meet criterion or not by using formula (1) according to current power frequency quantities at two ends of the hybrid circuit, and exchanging the criterion result with the opposite side; when both sides are not satisfied, judging as an out-of-area fault; when both sides meet the criterion, judging the fault as an intra-area fault;
Figure FDA0002947693200000031
in the formula ICDΦIs a differential current equal to the magnitude of the vector sum of the currents on both sides; i isRΦThe braking current is equal to the amplitude of the vector difference of the currents on the two sides; i isSETA constant value is enabled for the differential current.
9. The protection method for the hybrid line with reactor according to claim 6, wherein in the step (4), the specific step of determining the fault section includes:
when the fault is judged to be an intra-area fault, calculating whether the voltage at the joint of the hybrid circuit and the voltage power frequency of the on-site acquisition module meets the criterion by using the formula (2), and exchanging the criterion result with the opposite side; when the calculation of the line protection module at one side meets the requirement of one side, judging that the fault occurs in the mixed connection line section where the line protection module which does not meet the requirement is located; when the calculation of the line protection modules at the two sides meets the criterion condition, the fault is judged to occur in the parallel reactor section of the mixed connection line;
Figure FDA0002947693200000032
in the formula (I), the compound is shown in the specification,
Figure FDA0002947693200000033
in order to calculate the voltage at the connection position of the hybrid line according to the voltage current of the fault phase of the line at one side and the line impedance,
Figure FDA0002947693200000034
for the voltage at the junction of the hybrid line, ∈SETIs a set voltage error range.
CN202110197696.1A 2021-02-22 2021-02-22 Protection system and method for mixed connection line with reactor Pending CN112821364A (en)

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