CN103872660B - Network type protection method based on closed-loop mode operation of power network - Google Patents

Abstract

The network protection method based on the operation of the closed-loop mode of the power network is used for the power network system operating in the closed-loop mode. The power network system includes a plurality of substations and terminal units connected to the substations, and is characterized in that: each of the terminal units Including an intelligent controller, a circuit breaker and a communication module, the communication module in each terminal unit only communicates with the adjacent terminal unit, and the intelligent controller in each terminal unit collects information from this terminal unit and adjacent terminal units The voltage and current, power direction, associated direction, status and post-fault information of the circuit breaker in the circuit breaker. The invention adopts a peer-to-peer communication network, and the terminal units on the line communicate with each other, collect fault information of adjacent switches, make arbitration, and realize fast fault location and isolation.

Description

Network protection method based on power network closed-loop mode operation

technical field

The invention relates to a protection method for an intelligent power network, in particular to a network-type protection method suitable for the operation of a multi-power supply ring network structure and a full circuit breaker network.

Background technique

Power automation is an important part of the smart power network, and it is of great significance to improve the reliability of power supply, expand the power supply capacity and realize the efficient and economical operation of the power network. Power network fault handling is the core content of power automation. my country's distribution network generally adopts radial structure lines. When carrying out urban network transformation, it generally adopts the interconnection of the ends of the radiation lines to form a hand-in-hand dual power supply ring network structure. The method saves investment and can improve the reliability of power supply. At present, the network with this structure has a certain representativeness. In the cable system, a hand-in-hand ring network with dual power supplies is often used, but sometimes a multi-power supply network structure is used.

The ring network or mesh power supply network is generally segmented according to the length of the ring network line, load density and distribution. The number of segments directly affects the reliability of power supply, investment, operation management, protection setting and substation outlet protection. Its advantage is that a user's power supply can come from two or more different power supply points, and the power supply reliability is higher than that of a radial network.

The ring or mesh power supply network has a closed-loop type (the contact switch is in the closed state, and the same user can have two or more power supplies supplying power at the same time) and an open-loop type (the contact switch is in the open state, and the same user has only one power supply at any time. can supply power) two. Here we focus on the closed-loop mode of operation.

If the traditional protection is adopted, the closed-loop operation of the ring network has high requirements for relay protection settings and configurations, high investment, complicated setting, and high requirements for the quality of operating personnel. Or do not configure protection and adopt centralized control. When a fault occurs on the line, the on-site FTU sends the fault information to the control center through the communication channel, and the control center judges the faulty section according to the switch status, fault detection information, and network topology analysis, issues remote control commands, and performs a series of automatic operations , to reconfigure the network to isolate faults and restore power to non-faulty segments, this is the so-called centralized intelligence. This solution is accurate in control and suitable for various complex systems. But it requires reliable communication channels and computer software and hardware systems in the control center, and it takes a long time to complete a "location, isolation, and transfer".

For example, Chinese Patent No. CN200510024379.0, the patent of invention, published on September 20, 2006, discloses a method for controlling a power transmission network without a master station. The method for controlling a power transmission network includes: a fault detection step: corresponding power feeding The terminal unit detects the faulty power supply and sends fault information to all feeder terminal units; fault location step: the feeder terminal unit locates the fault point according to the fault information; fault isolation step: the feeder terminal unit at the fault point opens, and instructs The downstream feeder terminal unit opens; the step of opening report: the fault point feeder terminal unit and the downstream feeder terminal unit send status information; the power supply recovery step: the open loop point closes. Since the master station computer is not used in the control method of the present invention, even if the communication between individual feeder terminal units and the master station fails, the control algorithm of the present invention will automatically minimize the isolated fault without causing the entire network to fail to recover. In the above scheme, each feeder terminal needs to send information to all feeder terminals, and each feeder terminal needs to establish an information table of all feeder terminals, so as to realize control according to the status of all feeder terminals. The technical solution does not apply to the closed-loop model, but only applies to the situation where all feeder terminals communicate with each other normally and the full circuit breaker networking model. Each feeding terminal needs to send information to all feeding terminals, and each feeding terminal needs to establish an information table of all feeding terminals, which takes long processing time and slow response time.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the deficiencies of the above-mentioned prior art, and provide a network protection method based on power network closed-loop mode operation with fast response, light terminal burden and stable system.

According to a network protection method based on power network closed-loop mode operation provided by the present invention, it is used for a power network system operating in closed-loop mode, and the power network system includes a plurality of substations and terminal units connected to the substations, each of which The terminal unit includes an intelligent controller, a circuit breaker and a communication module, and the communication module in each terminal unit only communicates with the communication module in the adjacent terminal unit, and the intelligent controller in each terminal unit collects this Fault current, fault current direction, fault current associated direction, status and post-fault information for circuit breakers in terminal units and adjacent terminal units that detect a fault current and have no fault current on the side to which the fault current direction points outflow, the intelligent controller in the terminal unit starts the quick-break protection function or the overcurrent protection function, and trips; otherwise, the intelligent controller in the terminal unit is only used as a backup protection.

According to the present invention, a network-type protection method based on power network closed-loop mode operation also has the following subsidiary technical features:

A preferred embodiment is: each terminal unit has all or several of the following functions: quick-break protection function, over-current protection function, reclosing function, power-on reclosing function, short-time blocking protection function after successful reclosing, closing to fault Post-quick tripping function, interlocking power failure delay opening and locking function, power failure delay opening and non-blocking function, residual voltage pulse opening and locking function, unilateral voltage loss delay closing function, inspection lock unilateral voltage loss delay Closing function.

A preferred embodiment is: when the communication is normal, if a fault occurs between the circuit breaker of the terminal unit adjacent to the substation and the substation, the protection action is as follows:

A. After the outlet circuit breaker in the substation detects the fault current, it starts the quick-break protection function or the over-current protection function;

B. The intelligent controller in the terminal unit adjacent to the substation activates the quick-break protection function or the over-current protection function, and the circuit breaker trips.

A preferred embodiment is: when the communication is normal, if a fault occurs between the circuit breakers of the terminal unit, the protection action is as follows:

A. The intelligent controller in the terminal unit located on one side of the fault point starts the quick-break protection function or the over-current protection function, and the circuit breaker trips;

B. The intelligent controller in the terminal unit located on the other side of the fault point activates the quick-break protection function or the over-current protection function, and the circuit breaker trips.

A preferred embodiment is: when a fault occurs between the circuit breakers of the terminal unit, and the terminal unit that controls the circuit breaker closest to the terminal unit at the fault point has a communication abnormality, the protection action is as follows:

A. The intelligent controllers in the terminal units located on both sides of the fault point start the quick-break protection function or the over-current protection function, and the circuit breaker trips;

B. The intelligent controller located in the terminal unit with abnormal communication and the intelligent controller in the terminal unit in the upstream section adjacent to the terminal unit with abnormal communication starts the quick-break protection function or overcurrent protection function, and controls the respective circuit breakers to trip ;

C. Only the intelligent controller in the terminal unit that trips due to abnormal communication activates the power-on reclosing function and the short-term blocking protection function on successful reclosing, and the circuit breaker closes.

A preferred embodiment is: when the communication is normal, a fault occurs between the circuit breakers of the terminal unit, and the circuit breaker in the terminal unit is mechanically abnormal and refuses to move. The protection action is as follows:

A. The intelligent controllers in the terminal units located on both sides of the fault point start the quick-break protection function or the over-current protection function, and the circuit breaker trips;

B. Due to mechanical abnormality, the circuit breaker of the terminal unit in step A refuses to operate, and the intelligent controller of the terminal unit adjacent to the terminal unit with mechanical abnormality and in the backup state breaks the circuit after receiving the signal of refusal device trips.

A preferred embodiment is: when the communication is normal, a fault occurs between the circuit breaker of the terminal unit adjacent to the substation and the substation, and the circuit breaker in the terminal unit is mechanically abnormal and refuses to move. The protection action is as follows:

A. After the outlet circuit breaker in the substation detects the fault current, it starts the quick-break protection function or the over-current protection function;

B. The intelligent controller in the terminal unit adjacent to the substation starts the quick-break protection function or the over-current protection function, and issues an opening command. Due to mechanical abnormalities, the circuit breaker refuses to move;

C. The circuit breaker trips after the intelligent controller of the terminal unit which is adjacent to the terminal unit with mechanical abnormality and is in the standby state receives the signal of refusal to operate.

The communication module in the terminal unit communicates with the communication module in the adjacent terminal unit through the switch.

Compared with the prior art, the network protection method based on the operation of the closed-loop mode of the power network provided by the present invention has the following advantages: the present invention adopts a peer-to-peer communication network, and the terminal units on the line communicate with each other, collect phase Arbitrate the fault information of adjacent switches to realize fast fault location and isolation. It has the following advantages: 1. The correlation between the fault and itself can be judged from the fault current direction and associated direction of this node and related nodes; the logic algorithm is concise and reliable, and easy to implement. 2. It adopts the active release of fault information instead of the round-robin method used in the past, which is fast and has little impact on the line. 3. It can provide a backup plan to ensure that the fault can be removed quickly when the trip at the fault end fails. 4. It can be easily applied to power networks of various voltage levels without worrying about the connection structure of the network and the operation mode of the system.

Description of drawings

Figure 1 is a simplified diagram of the power network of the present invention.

Fig. 2 is a simplified diagram of another power network in the present invention.

Detailed ways

Referring to Fig. 1, a network protection method based on power network closed-loop mode operation provided by the present invention is used for a power network system operating in closed-loop mode, and the power network system includes multiple substations and terminal units connected to the substations , each of the terminal units includes an intelligent controller, a circuit breaker and a communication module, the communication module in each of the terminal units only communicates with the adjacent terminal units, and the intelligent controller in each of the terminal units collects this Fault current, fault current direction, fault current associated direction, status and post-fault information for circuit breakers in terminal units and adjacent terminal units that detect a fault current and have no fault current on the side to which the fault current direction points outflow, the intelligent controller of the terminal unit starts the quick-break protection function or the overcurrent protection function, and the circuit breaker trips; otherwise, the intelligent controller of the terminal unit is only used as a backup protection.

In the present invention, each terminal unit can control all circuit breakers in a ring main unit. The control principle is similar to a circuit breaker, and it can be set according to the same control principle. A circuit breaker given in the present invention is for the convenience of description and understanding. As the most basic control unit, it is not a limitation of the present invention. Those of ordinary skill in the art can extend it to multiple switches according to the most basic control unit. in the control unit. The main criterion source of the present invention is the fault current, fault current direction and fault current related direction of the circuit breaker itself and its adjacent circuit breakers, that is, when the communication is normal or abnormal, the circuit breaker at the end of the fault will feel the overcurrent , There is no fault current flowing out on the side where the direction of the fault current points, and the quick-break protection function or over-current protection function is activated, and the circuit breaker trips. Otherwise, it is only used as a backup protection.

In practical applications, as long as the same user has two or more power supplies supplying power at the same time, it can be regarded as a closed-loop mode. as shown in picture 2. The circuit breakers 12, 16, 21 connected to the left side of the circuit breaker 17 in Fig. 2 can be regarded as a circuit breaker group, and the circuit breakers 12, 18, 22 connected to the right side can also be regarded as a circuit breaker group. When a fault occurs, as long as any line in the left circuit breaker group has a fault current flowing into the circuit breaker 17, it can be regarded as a fault current flowing in; the same is true for the right side. It is equivalent to the structure of a switch provided by the present invention, and the judgment basis is still the protection method provided by the present invention.

In Figure 2 Indicates the switch in the open state; Indicates the switch in the open state; represents the reference direction of each edge, Represents the actual direction of the overcurrent.

The intelligent controller in each terminal unit in the present invention not only collects the fault current, fault current direction and fault current correlation direction of the circuit breakers in this terminal unit and adjacent terminal units, but also collects voltage, current, power direction, associated direction, circuit breaker status, and post-fault information. These parameters can be used as the judgment basis of the intelligent controller.

The terminal unit of the present invention only communicates with adjacent terminal units, adopts the distributed intelligent control mode, greatly reduces the processing information of each terminal unit, reduces the load of the processor, and shortens the action time. The invention introduces a new protection coordination scheme suitable for hand-in-hand double power supply ring network or multi-power supply ring network structure, which is called the closed-loop mode of peer-to-peer network protection. The scheme uses a peer-to-peer communication network, so that each intelligent controller can collect and comprehensively utilize its own fault status and information of other switches in the network, analyze and judge, and realize high-speed and selective action of the switch. It not only overcomes the dependence on the protection substation, but also ensures that the switch can operate correctly when any fault occurs in the line. Its purpose is, faster and higher reliability. It will be a brand-new protection concept, making the protection cooperation of the distribution network automation system go through the process from distribution to concentration, from concentration to distribution, using modern communication methods and simple and easy criteria to make the entire network interactive Coordination is completed more efficiently. The communication module in the terminal unit in the present invention can be set independently or integrated in an intelligent controller.

The power network system is a hand-in-hand power network system or a multi-power supply parallel power network system. The power network system may be of various voltage levels.

In the present invention, each terminal unit has all or several of the following functions: quick-break protection function, over-current protection function, reclosing function, power-on reclosing function, reclosing successful short-time blocking protection function, close-to-failure Post-quick tripping function, interlocking power failure delay opening and locking function, power failure delay opening and non-blocking function, residual voltage pulse opening and locking function, unilateral voltage loss delay closing function, inspection lock unilateral voltage loss delay Closing function.

The specific meanings of the above functions are:

1.1, quick break protection function

1) Network-type quick-break protection function under normal communication conditions:

The network communication is normal, there is no "blocking protection" sign --> self-overcurrent is greater than the quick trip value, the overcurrent direction is to the right and the right switch has no combined fault current flow out (or self-overcurrent, the overcurrent direction is to the left and the left switch No combined fault current flows out) -> the switch opens automatically;

2) The backup function of the network-type quick-break protection under normal communication conditions:

The network communication is normal, and there is no "blocking protection" sign—> self-overcurrent is greater than the quick trip value, the overcurrent direction is to the right and the right switch has a combined fault current flow out (or self-overcurrent, the overcurrent direction is to the left and the left switch Combined fault current flows out) --> fault current persists --> switch automatically opens after backup delay;

3) In the case of abnormal communication, the quick-break protection in the fault-tolerant state:

Abnormal network communication, no "blocking protection" sign -> self-over-current and greater than the fast judgment value, the over-current direction is to the right and the over-current state information of the right switch is incomplete or cannot be confirmed (or self-over-current, the over-current direction is to the left and The overcurrent state information of the switch on the left is incomplete or cannot be confirmed) —> the switch is automatically opened —> the fault-tolerant tripping flag is set

1.2. Overcurrent protection function

1) Network overcurrent protection function under normal communication conditions:

The network communication is normal (fault), there is no "blocking protection" sign -> self-overcurrent and the current is greater than the time-limited protection setting value and less than the quick-break value, the overcurrent direction is to the right and the right switch has no combined fault current flow out (or self-overcurrent, The overcurrent direction is to the left and there is no combined fault current flow out of the switch on the left side) —> the delay time is up —> the switch automatically opens;

2) Backup function of network overcurrent protection under normal communication conditions:

The network communication is normal, and there is no "blocking protection" sign —> self-overcurrent and the current is greater than the overcurrent protection setting value and less than the speed trip value, the overcurrent direction is to the right and the right switch has a combined fault current flow out (or self-overcurrent, overcurrent The direction is to the left and the left switch has a combined fault current flowing out) --> the fault current continues to exist --> the switch will automatically open after the overcurrent delay time plus the backup delay time;

3) In case of abnormal communication, overcurrent protection in fault-tolerant state:

Network communication is abnormal, there is no "blocking protection" sign -> self-overcurrent and the current is greater than the over-current protection setting value and less than the fast-breaking value. The over-current direction is to the left and the over-current status information of the left switch is incomplete or cannot be confirmed) —> the switch is automatically opened —> the fault-tolerant tripping flag is set.

1.3. Reclosing function

1) Reclosing function under normal conditions

Under normal communication conditions, the switch is not in the closed position after the switch breaks quickly/over-current protection trips —> there is no “lockout reclosing” sign, no “residual voltage pulse” —> “reclosing times” is greater than or equal to 1, and the “fault tripping” sign Set —> delay time is up —> switch closes automatically;

2) Reclosing function after backup protection action

Under normal communication conditions, the switch is not in the closed position after the switch quick break/over-current backup protection trips —> there is no "locking reclosing" sign, no "residual voltage pulse" —> "reclosing times" is greater than or equal to 1, and "fault tripping" The flag is set —> the delay time is up —> the switch closes automatically.

1.4. Power reclosing function

Reclosing function in fault-tolerant state:

There is voltage on one side of the switch --> the switch is not in the closed position --> the "fault-tolerant fault trip" flag is set, there is no "locked power reclosing" flag, no "residual voltage pulse" --> the delay time is up --> the switch closes automatically .

1.5. The short-term blocking protection function of successful reclosing

"Reclosing" or "energized reclosing" reclosing is successful --> "Locking protection flag" is set, and there is a fault current (fault current duration is greater than the protection delay, less than the protection delay + short-term blocking protection delay) --> The protection does not act —> the delay time is up —> the "blocking protection flag" is cleared.

1.6. Quick trip function after close to fault

After the switch closes —> “Reclosing” or “Electrical Reclosing” is reclosed, overcurrent is detected —> Set the delay time to —> The switch opens automatically.

1.7. Interlocking power failure delay opening and closing function

The network communication is normal (abnormal) —> self-voltage and current loss, receiving the adjacent switch “protection fault trip” (or “load switch fault trip”) sign —> delay time is up —> switch automatically opens and locks, set "Opening and locking" flag.

1.8. Power-off delay opening and non-blocking function

Generally used for switches in close proximity to power sources:

Loss of voltage and current by itself —> delay time is up —> the switch automatically opens and does not lock.

1.9. Residual voltage pulse opening and locking function

The switch is in position, and the residual voltage pulse is detected —> the sign of "opening not locked" is converted into a sign of "opening locked".

1.10. One-side voltage loss delay closing function

This function requires that even if the adjacent switch cannot be confirmed to be fault-free, the voltage loss will be transferred after a delay:

The position of the switch —> there is pressure on one side of the switch, there is no sign of "blocking and transfer", the communication is abnormal or the adjacent switch has no fault trip sign when the communication is normal —> the delay time is up —> the switch closes automatically.

1.11. Check and lock single-side pressure loss delay closing function

This function requires only confirming that the adjacent switch has no fault flag before it is possible to transfer:

The position of the switch —> the network communication is normal —> there is pressure on one side of the switch, there is no sign of “locking and transfer” and the adjacent switch has no fault trip sign —> the delay time is up —> the switch closes automatically.

Below in conjunction with the simplified diagram of the power network, when a fault occurs, an embodiment of the protection method of the present invention is specifically described:

Figure 1 is a simplified diagram of a power network operating in closed loop mode. S1, S2, S3, and S4 in Figure 1 are all circuit breakers; the circuit breakers S1, S2, S3, and S4 are closed when the system is in normal operation, thus forming a closed-loop mode. A terminal unit (including two sets of PTs) includes an intelligent controller and its controlled circuit breaker, and the intelligent controllers of the terminal unit exchange information with each other through the switch. Two substations are shown in Fig. 1, and the outlet circuit breakers CB1 and CB2 of the substation are set for one reclosing function.

Embodiment 1, when the communication is normal, a fault occurs between the circuit breaker of the terminal unit adjacent to the substation and the substation, that is, the fault point is point F1, and the protection action process is as follows:

A. After the outlet circuit breaker CB1 in the substation ES1 detects the fault current, it starts the quick-break protection function or the over-current protection function;

B. The intelligent controller in the terminal unit adjacent to the substation ES1 activates the quick-break protection function or the over-current protection function, and the circuit breaker S1 trips. Thereby isolating the point of failure.

Embodiment 2, when the communication is normal, a fault occurs between the circuit breakers of the terminal unit, that is, the fault point F2 in Figure 1, and the protection action process is as follows:

A. The intelligent controller in the terminal unit located on one side of the fault point starts the quick-break protection function or the over-current protection function, and the circuit breaker S1 trips;

B. The intelligent controller in the terminal unit located on the other side of the fault point activates the quick-break protection function or the over-current protection function, and the circuit breaker S2 trips. Thereby isolating the point of failure.

Embodiment 3, when the communication is normal, a fault occurs between the circuit breakers of the terminal unit, that is, the fault point F3 in Figure 1, and the protection action process is as follows:

A. The intelligent controller in the terminal unit located on one side of the fault point starts the quick-break protection function or the over-current protection function, and the circuit breaker S2 trips;

B. The intelligent controller in the terminal unit located on the other side of the fault point activates the quick-break protection function or the over-current protection function, and the circuit breaker S3 trips. Thereby isolating the point of failure.

Embodiment 4, when the communication is normal, a fault occurs between the circuit breakers of the terminal unit, that is, the fault point F4 in Figure 1, and the protection action process is as follows:

A. The intelligent controller in the terminal unit located on one side of the fault point starts the quick-break protection function or the over-current protection function, and the circuit breaker S3 trips;

B. The intelligent controller in the terminal unit located on the other side of the fault point activates the quick-break protection function or the over-current protection function, and the circuit breaker S4 trips. Thereby isolating the point of failure.

Embodiment 5, a fault occurs between the circuit breakers of the terminal unit, and the terminal unit that controls the circuit breaker closest to the terminal unit at the fault point has a communication abnormality, such as fault point F4 in Figure 1, circuit breaker S2 The intelligent controller in the terminal unit where it is located has a communication abnormality, and the protection action process is as follows:

A. The intelligent controllers in the terminal units located on both sides of the fault point start the quick-break protection function or the over-current protection function, and the circuit breakers S3 and S4 trip;

B. The intelligent controller located in the terminal unit with abnormal communication and the intelligent controller in the terminal unit in the upstream segment adjacent to the abnormal terminal unit starts the quick-break protection function or the overcurrent protection function, and the circuit breaker S2 and the circuit breaker Device S1 trips;

C. The intelligent controller in the terminal unit that only trips due to abnormal communication activates the power-on reclosing function and the short-term blocking protection function on successful reclosing, and the circuit breakers S1 and S2 are closed.

Embodiment 6, a fault occurs between the circuit breakers of the terminal unit, and a communication abnormality occurs in the terminal unit at the fault point, such as the fault point F4 in FIG. 1 , and the communication abnormality occurs in the terminal unit where the circuit breaker S3 is located. The protection action process is as follows:

A. The intelligent controllers in the terminal units located on both sides of the fault point start the quick-break protection function or the over-current protection function, and the circuit breakers S3 and S4 trip;

B. The intelligent controller located in the terminal unit with abnormal communication and the intelligent controller in the terminal unit adjacent to the terminal unit with abnormal communication starts the quick-break protection function or the overcurrent protection function, and the circuit breaker S2 trips (circuit breaker S3, S4 have tripped);

C. The intelligent controller in the terminal unit that only trips due to abnormal communication starts the power reclosing function and the short-term blocking protection function of successful reclosing, and the circuit breaker S2 is closed;

D. The intelligent controllers in the terminal units located on both sides of the fault point cause tripping due to abnormal communication and start the function of energized reclosing and quick tripping after closing to a fault. Circuit breakers S3 and S4 are closed first and then tripped.

From the above two embodiments, it can be seen that in the present invention, if the trip caused by communication abnormality is set, reclosing will be performed again, thereby eliminating the malfunction caused by communication abnormality. The circuit breaker at the fault point will start to trip quickly after closing to the fault to correct the trip caused by the transient fault. Through the above configuration, the present invention can accurately operate even in the case of abnormal communication, and complete the work of isolating the fault point.

Embodiment 7, when the communication is normal, a fault occurs between the circuit breakers of the terminal unit, and the circuit breaker in the terminal unit is mechanically abnormal and refuses to move, as in the fault point F2 in Figure 1, the circuit breaker S2 refuses to operate. The protection action process is as follows:

A. The intelligent controllers in the terminal units located on both sides of the fault point start the quick-break protection function or the over-current protection function, and the circuit breakers S1 and S2 trip;

B. Due to mechanical abnormality, the circuit breaker S2 of the terminal unit in step A refuses to operate, and the terminal unit adjacent to the terminal unit with mechanical abnormality and in the backup state receives the signal of refusal, and the circuit breaker S3 trips .

Embodiment 8, when the communication is normal, a fault occurs between the circuit breakers of the terminal unit, and the circuit breaker in the terminal unit is mechanically abnormal and refuses to operate, such as the fault point F3 in Figure 1, the circuit breaker S3 refuses to operate The protection action process is as follows:

A. The intelligent controllers in the terminal units located on both sides of the fault point start the quick-break protection function or the over-current protection function, and the circuit breakers S2 and S3 trip;

B. Due to mechanical abnormality, the circuit breaker S3 of the terminal unit in step A refuses to operate, and the terminal unit adjacent to the terminal unit with mechanical abnormality and in the backup state receives the signal of refusal, and the circuit breaker S4 trips .

Embodiment 9, when the communication is normal, a fault occurs between the circuit breakers of the terminal unit, and the circuit breaker in the terminal unit is mechanically abnormal and refuses to move, such as the fault point F4 in Figure 1, the circuit breaker S2 and S3 refuses to move, and the protection action process is as follows:

A. The intelligent controllers in the terminal units located on both sides of the fault point start the quick-break protection function or the over-current protection function, and the circuit breakers S3 and S4 trip;

B. Due to mechanical abnormality, the circuit breaker S3 of the terminal unit in step A refuses to operate. After the terminal unit adjacent to the terminal unit with mechanical abnormality and in the backup state receives the signal of refusal, the circuit breaker S2 The intelligent controller in the terminal unit of the terminal unit sends an opening command. Due to mechanical abnormalities, the circuit breaker S2 refuses to move. At this time, the intelligent controller in the terminal unit adjacent to the circuit breaker S2 and in the backup state After the refusal signal, the intelligent controller in the terminal unit where the circuit breaker S1 is located sends an opening command, and the circuit breaker S1 trips. When the machine is abnormal, the principle of tripping is that the terminal unit adjacent to the mechanical abnormality will replace the terminal unit with mechanical abnormality after receiving the rejection signal.

Embodiment 10, when the communication is normal, a fault occurs between the circuit breaker of the terminal unit adjacent to the substation and the substation, and the circuit breaker in the terminal unit is mechanically abnormal and refuses to move, such as the fault point F1 in Figure 1, The circuit breaker S1 refuses to move, and the protection action process is as follows:

A. After the outlet circuit breaker CB1 in the substation ES1 detects the fault current, it starts the quick-break protection function;

B. The intelligent controller in the terminal unit adjacent to the substation ES1 activates the quick-break protection function or the over-current protection function, and issues an opening command. Due to mechanical abnormalities, the circuit breaker S1 refuses to operate;

C. After the terminal unit adjacent to the terminal unit with mechanical abnormality and in the backup state receives the refusal signal, the circuit breaker S2 trips.

In the above implementation given by the present invention, each step will be repeated multiple times according to the set number of integrations, some of the steps are performed synchronously, and the order of some of the steps can be interchanged. The sequence of actions depends on whether the power is supplied or received. In the above-mentioned embodiments of the present invention, it is the intelligent controller in the terminal unit that activates relevant functions, and it is the circuit breaker that opens, trips or closes.

It can be clearly seen from the above embodiments that the present invention is not only applicable to protection under normal conditions, but also can realize protection against communication faults and mechanical abnormalities. Flexible and fast positioning and isolation of faults in various situations in the power network.

Claims (8)

1. The network protection method based on the operation of the closed-loop mode of the power network is used for the power network system of the closed-loop mode operation, and the power network system includes a plurality of substations and terminal units connected to the substations, characterized in that: each of the The terminal unit includes an intelligent controller, a circuit breaker and a communication module, and the communication module in each terminal unit only communicates with the adjacent terminal unit, and the intelligent controller in each terminal unit collects the Fault current, fault current direction, fault current associated direction, status and post-fault information of a circuit breaker in a terminal unit that detects a fault current and has no fault current flow on the side to which the fault current direction points, the said The intelligent controller in the terminal unit activates the quick-break protection function or the overcurrent protection function, and trips; otherwise, the intelligent controller in the terminal unit is only used as a backup protection. 2. The network protection method based on power network closed-loop mode operation as claimed in claim 1, wherein each terminal unit has all or several of the following functions: quick-break protection function, overcurrent protection function, Reclosing function, energized reclosing function, successful reclosing short-term blocking protection function, quick tripping function after closing to a fault, interlocking power-off delay opening and locking function, power-off delay opening and non-blocking function, residual voltage pulse branching Brake locking function, unilateral loss of voltage delay closing function, check and lock unilateral loss of voltage delay closing function. 3. The network protection method based on power network closed-loop mode operation as claimed in claim 2, characterized in that: when the communication is normal, a fault occurs between the circuit breaker of the terminal unit adjacent to the substation and the substation, and the protection action is as follows: A. After the outlet circuit breaker in the substation detects the fault current, it starts the quick-break protection function or the over-current protection function; B. The intelligent controller in the terminal unit adjacent to the substation activates the quick-break protection function or the over-current protection function, and the circuit breaker trips. 4. The network protection method based on power network closed-loop mode operation as claimed in claim 2, characterized in that: when the communication is normal, if a fault occurs between the circuit breakers of the terminal unit, the protection action is as follows: A. The intelligent controller in the terminal unit located on one side of the fault point starts the quick-break protection function or the over-current protection function, and the circuit breaker trips; B. The intelligent controller in the terminal unit located on the other side of the fault point activates the quick-break protection function or the over-current protection function, and the circuit breaker trips. 5. The network protection method based on power network closed-loop mode operation according to claim 2, characterized in that: when a fault occurs between the circuit breakers of the terminal unit, the nearest control circuit breaker of the terminal unit at the fault point The terminal unit of the above-mentioned terminal unit has a communication abnormality, and the protection action is as follows: A. The intelligent controllers in the terminal units located on both sides of the fault point start the quick-break protection function or the over-current protection function, and the circuit breaker trips; B. The intelligent controller located in the terminal unit with abnormal communication and the intelligent controller in the terminal unit in the upstream section adjacent to the terminal unit with abnormal communication starts the quick-break protection function or overcurrent protection function, and controls the respective circuit breakers to trip ; C. Only the intelligent controller in the terminal unit that trips due to abnormal communication activates the power-on reclosing function and the short-term blocking protection function on successful reclosing, and the circuit breaker closes. 6. The network protection method based on power network closed-loop mode operation according to claim 2, characterized in that: when the communication is normal, a fault occurs between the circuit breakers of the terminal unit, and the circuit breaker in the terminal unit If the device is mechanically abnormal and refuses to move, the protection action is as follows: A. The intelligent controllers in the terminal units located on both sides of the fault point start the quick-break protection function or the over-current protection function, and the circuit breaker trips; B. Due to mechanical abnormality, the circuit breaker of the terminal unit in step A refuses to operate, and the intelligent controller of the terminal unit adjacent to the terminal unit with mechanical abnormality and in the backup state breaks the circuit after receiving the signal of refusal device trips. 7. The network protection method based on power network closed-loop mode operation according to claim 2, characterized in that: when the communication is normal, a fault occurs between the circuit breaker of the terminal unit adjacent to the substation and the substation, and the terminal unit The circuit breaker in the unit is mechanically abnormal and refuses to operate. The protection action is as follows: A. After the outlet circuit breaker in the substation detects the fault current, it starts the quick-break protection function or the over-current protection function; B. The intelligent controller in the terminal unit adjacent to the substation starts the quick-break protection function or the over-current protection function, and issues an opening command. Due to mechanical abnormalities, the circuit breaker refuses to move; C. The circuit breaker trips after the intelligent controller of the terminal unit which is adjacent to the terminal unit with mechanical abnormality and is in the standby state receives the signal of refusal to operate. 8. The network protection method based on power network closed-loop mode operation according to claim 1, characterized in that: the communication module in the terminal unit communicates with the communication module in the adjacent terminal unit through a switch.