A busbar protection method based on the protection system logic loop state

Abstract

The present invention relates to a busbar protection method based on the state of a protection system logic circuit, comprising the following steps: obtaining the state information of the system logic circuit, performing logical judgment on the state information, and determining that the busbar protection is locked when the circuit has state information that the busbar protection is locked and the protection is out of service; determining whether the circuit issues a protection outage when the circuit has state information that the busbar protection is locked and a fault excitation is applied, or issues an applied fault excitation and the interval is a maintenance interval and all circuit breakers that should trip in the interval receive a trip signal, and if so, determining that the busbar has a risk of refusal to operate; determining that the circuit has a risk of malfunction when the circuit issues an applied fault excitation and any circuit breaker in the interval receives a trip signal and the protection is out of service. Compared with the prior art, the present invention has the ability to intuitively and efficiently obtain the busbar protection state, and is convenient for determining whether the pressure plate operation will cause the busbar protection to have a risk of malfunction, refusal to operate, or mallocking.

Description

Technical Field

[0001] The invention relates to the field of substation circuit protection, and in particular to a busbar protection method based on the logic circuit state of a protection system. Background Art

[0002] At present, smart substations have been widely used. Compared with traditional substations that communicate with primary and secondary devices through cables, smart substations use optical fiber to transmit sampled value (SV) messages and general object-oriented substation events (GOOSE) messages according to the IEC61850 standard to communicate between primary and secondary devices in substations. The correspondence between virtual terminals replaces the traditional connection between the cables between primary and secondary devices, and the switch state change of the soft pressure plate controls the opening and closing of the connection between the primary and secondary devices. This makes the signal collection of the protection device, the sending of the trip command and other functions depend on the accurate connection of the virtual terminals and the correct setting of the pressure plate throw and retreat status. Summary of the invention

[0003] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide a busbar protection method based on the logic loop state of the protection system.

[0004] The purpose of the present invention can be achieved by the following technical solutions:

[0005] A busbar protection method based on the state of a protection system logic loop comprises the following steps:

[0006] Acquire the status information of the system logic circuit, the status information includes busbar protection blocking, applied fault excitation, this interval is a maintenance interval, all circuit breakers that should trip in this interval have received a trip signal, any circuit breaker in this interval has received a trip signal, and protection is out of service,

[0007] Perform logical judgment on the status information. When the circuit has status information that the bus protection is locked and the protection is out of service, determine that the bus protection is locked; when the circuit has status information that the bus protection is locked and a fault excitation is applied, or a fault excitation is applied and the interval is a maintenance interval and all circuit breakers that should trip in this interval receive a tripping signal, determine whether the circuit issues a protection outage. If so, determine that the bus has a risk of refusal to operate; when the circuit issues an applied fault excitation and any circuit breaker in this interval receives a tripping signal and the protection is out of service, determine that the circuit has a risk of false operation.

[0008] Preferably, the method for determining the state information of the busbar protection lockout is:

[0009] Obtain the alarm signal of all protections of the circuit and the busbar protection locking signal of each branch. When the alarm signal of all protections is issued or any branch issues a busbar protection locking signal, it is determined that the circuit issues a busbar protection lockout.

[0010] Preferably, the method for determining whether the branch sends a busbar protection locking signal is:

[0011] Obtain the merging unit maintenance signal, interval receiving pressure plate signal and busbar protection device maintenance signal of the current branch. When one of the merging unit maintenance signal and busbar protection device maintenance signal of the current branch is sent, and the current branch sends an interval receiving pressure plate signal, determine that the current branch sends a busbar protection lockout signal.

[0012] Preferably, the method for determining the state information of applying the fault excitation amount is:

[0013] The maintenance interval, associated interval and fault simulation information of the circuit are obtained. When the current interval is a maintenance interval or an associated interval and a fault simulation is performed in the current interval, it is determined that the circuit issues a fault excitation amount.

[0014] Preferably, the method for determining the state information that each circuit breaker that should trip in the interval has received a trip signal is:

[0015] The tripping signal and the input status of each branch are obtained. When all branches have tripping signals and are all input, it is determined that all circuit breakers that should trip in this interval have received the tripping signal.

[0016] Preferably, the method for determining whether a branch has a trip signal is:

[0017] Obtain and determine whether the voltage fault signal, bus voltage merging unit receiving pressure plate signal, bus differential action signal, bus protection device maintenance signal, current branch intelligent terminal maintenance signal, and protection tripping soft pressure plate signal are all sent out. If so, determine that the current branch has a tripping signal.

[0018] Preferably, the method for determining the mother differential action signal is:

[0019] Obtain and determine whether the busbar protection lockout signal and the large differential current fault signal are both issued. If so, determine whether the circuit has a bus differential action signal.

[0020] Preferably, the method for determining whether any circuit breaker in the interval has received the state information of the trip signal is:

[0021] The tripping signals of each branch are obtained. When any branch has a tripping signal, it is determined that any circuit breaker in this interval has received a tripping signal.

[0022] Preferably, the method for determining whether a branch has a trip signal is:

[0023] Obtain and determine whether the voltage fault signal, bus voltage merging unit receiving pressure plate signal, bus differential action signal, bus protection device maintenance signal, current branch intelligent terminal maintenance signal, and protection tripping soft pressure plate signal are all sent out. If so, determine that the current branch has a tripping signal.

[0024] Preferably, the method for determining the mother differential action signal is:

[0025] Obtain and determine whether the busbar protection lockout signal and the large differential current fault signal are both issued. If so, determine whether the circuit has a bus differential action signal.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] (1) The present invention can effectively obtain the changes in the state of the busbar protection logic circuit caused by different combinations of pressure plate operations required during operation and maintenance, and can judge whether the pressure plate operation will cause the busbar protection to have the risk of false operation, refusal to operate or false locking by means of fault simulation. The acquisition effect is good and the accuracy is high, avoiding the risk of insufficient isolation and false operation / refusal to operate caused by maintenance operation errors and other behaviors

[0028] (2) The acquisition of status information and signals of the present invention, based on the signal collection and trip command sending functions of the protection device, does not need to rely on the accurate connection of the virtual terminal and the status of the pressure plate. The busbar protection is performed based on the basic principle of relay protection, and only the virtual terminals and pressure plates that can affect the protection action and locking are used. Therefore, it can be applied to busbar protection devices produced by different manufacturers and using different protection principles, and has good reusability. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Determine a logic diagram for the protection status of the present invention;

[0030] Figure 2 Determine a logic diagram for busbar protection interlocking of the present invention;

[0031] Figure 3 Determine a logic diagram for the branch bus protection blocking signal of the present invention;

[0032] Figure 4 Determine the logic diagram for applying the fault excitation amount of the present invention;

[0033] Figure 5 A logic diagram for determining that each circuit breaker that should trip in this bay of the present invention receives a trip signal;

[0034] Figure 6 Any circuit breaker in this interval of the present invention receives a trip signal;

[0035] Figure 7 Determine a logic diagram for the branch bus trip signal of the present invention;

[0036] Figure 8 Determine a logic diagram for the mother differential action signal of the present invention;

[0037] Fig. 9 This is a logic diagram for generating a bus differential current fault signal of the present invention. DETAILED DESCRIPTION

[0038] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. Note that the following embodiments are merely illustrative in nature, and the present invention is not intended to limit its applicable objects or uses, and the present invention is not limited to the following embodiments.

[0039] Example

[0040] A busbar protection method based on the state of the protection system logic loop is a simulation method. A simulation model is established in the power system simulation software according to the actual power system operation status. Figure 1 As shown, the state of busbar protection is determined, and the simulation model judges and protects the busbar state according to the following steps:

[0041] Acquire the status information of the system logic circuit, the status information includes busbar protection blocking, applied fault excitation, this interval is a maintenance interval, all circuit breakers that should trip in this interval have received a trip signal, any circuit breaker in this interval has received a trip signal, and protection is out of service,

[0042] Perform logical judgment on the status information. When the circuit has status information that the bus protection is locked and the protection is out of service, determine that the bus protection is locked; when the circuit has status information that the bus protection is locked and a fault excitation is applied, or a fault excitation is applied and the interval is a maintenance interval and all circuit breakers that should trip in this interval receive a tripping signal, determine whether the circuit issues a protection outage. If so, determine that the bus has a risk of refusal to operate; when the circuit issues an applied fault excitation and any circuit breaker in this interval receives a tripping signal and the protection is out of service, determine that the circuit has a risk of false operation.

[0043] Among them, the judgment logic of the simulation model to obtain each state information is as follows.

[0044] like Figure 2 , 3 The following is the logic of generating the busbar protection blocking signal. The modeling principle is: the SV pressure plate is put into operation and the maintenance status of the merging unit and the protection device are inconsistent. Figure 2 As shown in the figure, the method for judging the status information of busbar protection locking is:

[0045] Obtain the alarm signal of the circuit's blocking all protections and the busbar protection blocking signal of each branch. When the alarm signal of blocking all protections is issued or any branch issues a busbar protection blocking signal, the circuit is judged to have issued a busbar protection blocking. Figure 3 As shown, the method for determining whether a branch sends a busbar protection lockout signal is as follows: obtain the merging unit maintenance signal, the interval receiving pressure plate signal and the busbar protection device maintenance signal of the current branch; when one of the merging unit maintenance signal and the busbar protection device maintenance signal of the current branch is sent, and the current branch sends an interval receiving pressure plate signal, it is determined that the current branch sends a busbar protection lockout signal.

[0046] The inconsistency between the maintenance status of the merging unit of each line connected to the busbar and the busbar protection device may lead to busbar protection lockout. The lockout signals (i.e. "busbar protection lockout 6" - "busbar protection lockout 13") generated by the inconsistency between the maintenance status of each branch merging unit and the busbar protection are ORed to obtain the final "busbar protection lockout".

[0047] Taking the busbar protection of double busbar non-segmented wiring as an example, the logic of generating busbar differential current fault signal is as follows: Fig. 9 As shown in the figure, in the bus differential protection, the occurrence of differential current faults mainly occurs in the following three situations: (1) A fault occurs in the bus area of ​​the primary equipment, causing the bus protection to sense the differential current fault, which is reflected in the simulation model as "applying a fault excitation signal". (2) A current signal that should have participated in the calculation is missing in the differential current calculation, causing the bus protection to sense the differential current fault, which is reflected in the simulation model as "branch input status" is true, but "interval receiving pressure plate" is false. (3) The interval receiving pressure plate of the power-off branch is not withdrawn, and the power-off branch applies a fault excitation, causing the bus protection to sense the differential current fault, which is reflected in the simulation model as "branch input status" is false, "interval receiving pressure plate" is true, and the branch's "execute secondary operation verification" is true.

[0048] like Figure 4 As shown in the figure, the principle of modeling the applied fault excitation is: when the fault simulation is performed in this interval, if this interval belongs to the associated interval or the maintenance interval, then the "apply fault excitation" is true. The specific method for determining the state information of the applied fault excitation is:

[0049] The maintenance interval, associated interval and fault simulation information of the circuit are obtained. When the current interval is a maintenance interval or an associated interval and a fault simulation is performed in the current interval, it is determined that the circuit issues a fault excitation amount.

[0050] The state determination logic of busbar protection is as follows: Figure 1 , Figure 5 , Figure 6As shown in Figure 1, remote backup protection is not considered in this model, that is, the situation where no fault simulation is performed on this interval and a tripping output is generated is ignored. Figure 5 As shown, the method for judging the status information that each circuit breaker that should trip in this interval has received the trip signal is:

[0051] The tripping signal and the input status of each branch are obtained. When all branches have tripping signals and are all input, it is determined that all circuit breakers that should trip in this interval have received the tripping signal.

[0052] like Figure 6 As shown, the method for determining whether any circuit breaker in the interval has received the state information of the trip signal is:

[0053] The tripping signals of each branch are obtained. When any branch has a tripping signal, it is determined that any circuit breaker in this interval has received a tripping signal.

[0054] Among them, Figure 7 , 8 The figure shows the main logic of busbar protection, which mainly describes the generation of action signals and their output conditions. Specifically, the method for judging whether a branch has a tripping signal is as follows:

[0055] Obtain and determine whether the voltage fault signal, bus voltage merging unit receiving pressure plate signal, bus differential action signal, bus protection device maintenance signal and current branch intelligent terminal maintenance signal, protection trip soft pressure plate signal are all sent out. If so, determine that the current branch has a trip signal. The method for determining the bus differential action signal is:

[0056] Obtain and determine whether the busbar protection lockout signal and the large differential current fault signal are both issued. If so, determine whether the circuit has a bus differential action signal.

[0057] In this embodiment, the present invention first simplifies the logic circuit of the busbar protection of the smart substation based on the basic principle of relay protection. Then, the logic circuit and related pressure plates are extracted for the functions of the busbar protection device action and locking in the smart substation for modeling. Finally, on this basis, a simulation model of the smart substation busbar protection is constructed that can intuitively display the changes in the logic circuit state under different pressure plate operation combinations.

[0058] The basic principle of relay protection refers to the protection action principle of relay protection devices such as current protection, distance protection, differential protection, etc. The action process of the relay protection device is essentially a process in which the protection device performs a series of logical judgments based on the received SV signal to obtain an action signal, which is then transmitted to the corresponding intelligent terminal and generates a tripping output.

[0059] The logic circuit of the busbar protection of the intelligent substation refers to: the circuit in the busbar protection device of the intelligent substation that performs logical judgment based on the sampling value and the pressure plate status so that the specified actions such as action and locking can be correctly executed.

[0060] The simplification of the busbar protection logic circuit of the smart substation means that in the simulation, the specific setting parameter values ​​of the actual protection device are not paid attention to, but the merging unit model directly sends digital signals instead of the voltage and current signals containing specific numerical information in the actual situation. When the fault excitation signal value sent by the merging unit is 1, it means that the system is in a fault state; when the value is 0, it means that the system is in a normal state, that is, there is no fault. If a trip signal successfully reaches the smart terminal and exits after passing through the logic circuit of the busbar protection model, it is considered that the protection has taken action.

[0061] The pressure plates related to the busbar protection device action, locking and other functions refer to the pressure plates that affect the busbar protection device to complete the protection action, protection locking and other actions, including maintenance hard pressure plates, tripping outlet pressure plates, SV sampling value pressure plates, etc. Different pressure plate operation combinations refer to a series of pressure plate opening and closing operations performed before the operation and maintenance task to keep the protection device in a safe state to prevent it from being affected by the operation and maintenance and causing false operation, refusal to operate or false locking.

[0062] The change of logic circuit state refers to: the malfunction, refusal to operate or mallocking state of the busbar protection device.

[0063] The busbar protection simulation model proposed in the present invention is constructed by simplifying the protection action process of the relay protection device and abstracting it into a signal flow model. A complete busbar protection simulation model is constructed according to the signal flow relationship in the busbar protection and the influence of each pressure plate on the signal flow.

[0064] The logical function of busbar protection is closely related to line protection, so the busbar protection simulation model proposed in the present invention includes relevant pressure plates of line intervals.

[0065] In addition, the protection device needs to receive at least one current SV signal normally to successfully sense the differential current.

[0066] Specifically, when the present invention is implemented, taking the failure elimination of 220kV busbar protection A device as an example, the implementation process of using the busbar protection simulation method proposed in the present invention to judge the status of the busbar protection device is explained.

[0067] Table 1 shows the combination of operations required to eliminate the fault of busbar protection device A. The maintenance interval is the 220kV busbar interval, and the associated intervals are line 8 interval, line 9 interval, line 10 interval, and main transformer interval. Set the initial value of each pressure plate in the simulation system according to the pressure plate state during normal operation.

[0068] Table 1 Operational measures for eliminating faults in busbar protection device A

[0069]

[0070] Perform fault simulation on the maintenance interval. Perform the operations in Table 1 in sequence, and after any maintenance pressure plate of the IED in this interval is put into operation, set the "Fault simulation for this interval" signal of the busbar protection simulation model to true, and verify the malfunction risk of the maintenance interval and the associated interval. Then perform fault simulation on the associated interval. Set the "Fault simulation for this interval" corresponding to the associated interval to true, and perform the operations in Table 1 in sequence. After verification, it can be found that during the operation, there is no malfunction, refusal to operate, or erroneous locking in the maintenance interval and the associated interval.

[0071] The above embodiments are merely examples and do not limit the scope of the present invention. These embodiments can also be implemented in various other ways, and various omissions, substitutions, and changes can be made without departing from the technical concept of the present invention.

Claims

1. A busbar protection method based on the protection system logic loop state, characterized in that: The following steps are involved: Acquire the status information of the system logic circuit, the status information includes busbar protection blocking, applied fault excitation, this interval is a maintenance interval, all circuit breakers that should trip in this interval have received a trip signal, any circuit breaker in this interval has received a trip signal, and protection is out of service, Perform logical judgment on the status information. When the circuit has status information that the busbar protection is locked and the protection is out of service, determine that the busbar protection is locked; when the circuit has status information that the busbar protection is locked and a fault excitation is applied, or an applied fault excitation is issued and the interval is a maintenance interval and all circuit breakers that should trip in this interval receive a trip signal, determine whether the circuit issues a protection outage. If so, determine that the busbar has a risk of refusal to operate; when the circuit issues an applied fault excitation and any circuit breaker in this interval receives a trip signal and the protection is out of service, determine that the circuit has a risk of malfunction; The method for determining the state information of the busbar protection lockout is as follows: Obtain the alarm signal of the circuit's blocking all protections and the busbar protection blocking signal of each branch. When the alarm signal of blocking all protections is issued or any branch issues a busbar protection blocking signal, it is determined that the circuit issues a busbar protection blocking signal. The method for judging whether the branch sends a busbar protection blocking signal is as follows: Obtain the merging unit maintenance signal, interval receiving pressure plate signal and busbar protection device maintenance signal of the current branch. When one of the merging unit maintenance signal and busbar protection device maintenance signal of the current branch is sent, and the current branch sends an interval receiving pressure plate signal, determine that the current branch sends a busbar protection locking signal; The method for judging the status information that each circuit breaker that should trip in the interval has received the trip signal is as follows: The tripping signal and the input status of each branch are obtained. When all branches have tripping signals and are all input, it is determined that all circuit breakers that should trip in this interval have received the tripping signal.

2. A busbar protection method based on the protection system logic loop state according to claim 1, characterized in that: The method for determining the state information of the applied fault excitation amount is as follows: The maintenance interval, associated interval and fault simulation information of the circuit are obtained. When the current interval is a maintenance interval or an associated interval and a fault simulation is performed in the current interval, it is determined that the circuit issues a fault excitation amount.

3. According to the busbar protection method based on the protection system logic loop state as described in claim 1, it is characterized in that: The method for judging whether the branch has a trip signal is as follows: Obtain and determine whether the voltage fault signal, bus voltage merging unit receiving pressure plate signal, bus differential action signal, bus protection device maintenance signal, current branch intelligent terminal maintenance signal, and protection tripping soft pressure plate signal are all sent out. If so, determine that the current branch has a tripping signal.

4. A busbar protection method based on the protection system logic loop state according to claim 3, characterized in that: The method for determining the mother differential action signal is as follows: Obtain and determine whether the busbar protection lockout signal and the large differential current fault signal are both issued. If so, determine that the circuit has a bus differential action signal.

5. A busbar protection method based on the protection system logic loop state according to claim 1, characterized in that: The method for determining whether any circuit breaker in the interval has received the state information of the trip signal is as follows: The tripping signals of each branch are obtained. When any branch has a tripping signal, it is determined that any circuit breaker in this interval has received a tripping signal.

6. A busbar protection method based on the protection system logic loop state according to claim 5, characterized in that: The method for judging whether the branch has a trip signal is as follows: Obtain and determine whether the voltage fault signal, bus voltage merging unit receiving pressure plate signal, bus differential action signal, bus protection device maintenance signal, current branch intelligent terminal maintenance signal, and protection tripping soft pressure plate signal are all sent out. If so, determine that the current branch has a tripping signal.

7. A busbar protection method based on the protection system logic loop state according to claim 6, characterized in that: The method for determining the mother differential action signal is as follows: Obtain and determine whether the busbar protection lockout signal and the large differential current fault signal are both issued. If so, determine that the circuit has a bus differential action signal.

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