SYSTEM AND METHOD FOR DETECTING FAILURE FOR CUT-OFF OF 23kV POWER NETWORK

Abstract

A system and method for detecting a 23kV transformer tripping failure are provided. The 23kV transformer tripping failure detection system includes i) a distribution line protection IED included in each of a plurality of distribution lines connected to a 23kV transformer, ii) a transformer secondary control IED included on the secondary side of the 23kV transformer, and iii) a transformer protection IED included in the 23kV transformer. The distribution line protection IED outputs whether each distribution line has tripped and inputs the tripping failure output to the transformer secondary control IED. The transformer secondary control IED outputs a comprehensive tripping failure based on the tripping failure outputs of each of the plurality of distribution lines. The transformer protection IED determines whether the circuit breaker on the secondary side of the 23kV transformer opens by judging the output of the transformer secondary control IED and the current element of the 23kV transformer.

Description

Technology Field

[0001] The present invention relates to a system for detecting circuit breaker failure and a method for detecting circuit breaker failure in a 23kV power system. More specifically, the present invention relates to a system for detecting a circuit breaker failure that occurs when a 23kV circuit breaker does not operate or operates with a delay when a fault occurs in a distribution line connected to a 23kV transformer, and a method for detecting the circuit breaker failure. Background Technology

[0002] When a fault occurs in a distribution line, the failure of a circuit breaker to open normally due to non-operation or delayed operation, resulting in the continued inflow of fault current, is called a circuit breaker failure. Generally, 345kV and 154kV transformers are equipped with devices or logic that protect connected equipment after detecting a circuit breaker failure, allowing the fault to be cleared within a critical time.

[0003] In 23kV transformers, only the transformer's backup protection relay operates when a tripping failure occurs. Consequently, the tripping time in the event of a tripping failure does not satisfy the critical time. As a result, there is a problem where fault current flows into the main equipment for an unnecessarily long period. The problem to be solved

[0004] The present invention aims to provide a system for detecting circuit breaker failures in a 23kV power system. Furthermore, the present invention aims to provide a method for detecting circuit breaker failures in a 23kV power system. means of solving the problem

[0005] A circuit breaker failure detection system for a 23kV power system according to one embodiment of the present invention includes: i) a distribution line protection IED (intelligent electric device) connected to a plurality of distribution lines connected to the secondary side of a 23kV transformer and monitoring each of the plurality of distribution lines; ii) a transformer secondary control IED installed on the secondary side of a 23kV transformer; and iii) a transformer protection IED included in the 23kV transformer.

[0006] The distribution line protection IED transmits whether each of the multiple distribution lines has failed to trip to the transformer secondary control IED. The transformer secondary control IED determines whether there has been an overall trip failure based on the trip failure and transmits this to the transformer protection IED. The transformer protection IED determines whether to open the secondary circuit breaker of the 23kV transformer based on the determination of the overall trip failure and the determination of the current element of the 23kV transformer.

[0007] A distribution line protection IED can detect whether the distribution line has failed to interrupt the power line based on the current flowing into the distribution line and the status of multiple disconnectors installed on each of the multiple distribution lines. If an overcurrent is detected by one or more relays among the OCR (Over Current Relay) and OCGR (Over Current Ground Relay) installed on the distribution line, it can be determined that an overcurrent has been detected in the distribution line. If no overcurrent is detected by either the OCR or the OCGR, it can be determined that no overcurrent has been detected in the distribution line.

[0008] Multiple disconnectors may include a first disconnector and a second disconnector. If one or more of the first disconnector and the second disconnector are in a closed state, the distribution line protection IED may determine that the distribution line is energized. If both the first disconnector and the second disconnector are in a disconnected state, the distribution line protection IED may determine that the distribution line is de-energized. The distribution line protection IED may determine whether the distribution line has failed to disconnect based on the overcurrent of the distribution line and the energized or de-energized state of the distribution line. The distribution line protection IED may determine that the distribution line has failed to disconnect only when the distribution line is in an overcurrent state and the distribution line is energized. If one or more of the overcurrent state and the energized state of the distribution line are not satisfied, the distribution line may not be determined to have failed to disconnect.

[0009] The transformer secondary control IED can take the output of each of the second distribution line protection IEDs as input. If at least one of the outputs is a failure to interrupt the distribution line, it can be determined as a total failure to interrupt. If the outputs of each of the second distribution line protection IEDs are not all determined as failures to interrupt the second distribution line, the transformer secondary control IED may not determine as a total failure to interrupt.

[0010] The transformer protection IED can determine the current element of the 23kV transformer based on the maximum rated current of the 23kV transformer. If a total trip failure is determined by the transformer secondary control IED and the transformer protection IED detects a current of 150% or more of the maximum rated current, the transformer protection IED may open the secondary circuit breaker only if the same condition is maintained even after a set operation delay time. The transformer protection IED can determine the current element of the 23kV transformer based on the maximum rated current of the 23kV transformer. If a total trip failure is determined by the transformer secondary control IED and the transformer protection IED detects a current of 150% or more of the maximum rated current, and the current of the 23kV transformer becomes less than 150% of the maximum rated current after a set operation delay time, the transformer protection IED may not open the secondary circuit breaker. The set operation delay time may be 0.2 seconds.

[0011] In a method for detecting a circuit breaker failure in a 23kV power system according to one embodiment of the present invention, i) a distribution line protection IED connected to a plurality of distribution lines connected to the secondary side of a 23kV transformer in the 23kV power system and monitoring each of the plurality of distribution lines, a transformer secondary control IED installed on the secondary side of a 23kV transformer, and a transformer protection IED included in the 23kV transformer are each installed. The method for detecting a circuit breaker failure includes a first step in which the distribution line protection IED transmits whether there is a circuit breaker failure of each of the plurality of distribution lines to the transformer secondary control IED, a second step in which the transformer secondary control IED determines whether there is an overall circuit breaker failure based on whether there is a circuit breaker failure and transmits this to the transformer protection IED, and a third step in which the transformer protection IED determines whether there is an overall circuit breaker failure and whether there is an overall circuit breaker failure based on the determination of the current element of the 23kV transformer and whether the circuit breaker on the secondary side of the 23kV transformer is opened.

[0012] Step 1 may include Step 1-1, which detects whether the distribution line has failed to disconnect based on the current flowing into the distribution line and the status of a plurality of disconnectors installed on each of the plurality of distribution lines; Step 1-2, which determines that an overcurrent has been detected in the distribution line when an overcurrent is detected by one or more of the OCR and OCGR relays installed on the distribution line; and Step 1-3, which determines that an overcurrent has not been detected in the distribution line when no overcurrent is detected by either the OCR or the OCGR. In Step 1-1, the plurality of disconnectors may include a first disconnector and a second disconnector. Step 1-1 may include i) a step in which the distribution line protection IED determines that the distribution line is energized when one or more of the first disconnect switch and the second disconnect switch are in an energized state, and ii) a step in which the distribution line protection IED determines that the distribution line is de-energized when both the first disconnect switch and the second disconnect switch are in an energized state. Step 1-1 may further include a step in which the distribution line protection IED determines whether the distribution line fails to disconnect based on the overcurrent of the distribution line and the energized or de-energized state of the distribution line. The step of determining whether the distribution line has failed to cut off may include: i) a step in which the distribution line protection IED determines the distribution line has failed to cut off only when the distribution line is in an overcurrent state and the distribution line is in a energized state; and ii) a step in which the distribution line protection IED does not determine the distribution line has failed to cut off when one or more of the overcurrent state of the distribution line and the energized state of the distribution line are not satisfied.

[0013] The second step may include a second-1 step in which the transformer secondary control IED takes the output of each of the second distribution line protection IEDs as input, and a second-2 step in which the transformer secondary control IED determines that there is a total failure of interruption if at least one of the outputs is a failure of interruption of the distribution line. The second step may further include a second-3 step in which the transformer secondary control IED does not determine that there is a total failure of interruption if the outputs of each of the second distribution line protection IEDs are not all determined to be failures of interruption of the second distribution line.

[0014] The third step may include a third-1 step in which the transformer protection IED determines the current element of the 23kV transformer based on the maximum rated current of the 23kV transformer, and a third-2 step in which the transformer protection IED opens the secondary circuit breaker only if the same condition is maintained after a set operation delay time when the transformer protection IED determines that there is a total circuit breaker failure and the transformer protection IED detects a current of 150% or more of the maximum rated current.

[0015] Alternatively, the third step may include a third-1 step in which the transformer protection IED determines the current element of the 23kV transformer based on the maximum rated current of the 23kV transformer, and a third-2 step in which the transformer protection IED does not open the secondary circuit breaker if the transformer protection IED determines that there is a total trip failure and the transformer protection IED detects a current greater than 150% of the maximum rated current and the current of the 23kV transformer becomes less than 150% of the maximum rated current after a set operation delay time. In the third-2 step, the set operation delay time may be 0.2 seconds. Effects of the invention

[0016] By determining the presence of overcurrent and the opening / closing status of the disconnect switch, it is possible to easily detect tripping failures in a 23kV power system. Since tripping failures in a faulty 23kV power system can be detected quickly, the circuit breaker can be opened within the critical time to prevent equipment damage. Furthermore, system operators can verify the tripping failure event when a tripping failure occurs. Consequently, faster fault recovery is possible without human error. Brief explanation of the drawing

[0017] FIG. 1 is a schematic power system diagram showing the operation of a blocking failure detection system according to one embodiment of the present invention. Figure 2 is a logic circuit diagram for verifying the interruption failure of a distribution line protection IED included in the interruption failure detection system of Figure 1. Figure 3 is a logic circuit diagram for comprehensive circuit failure verification of a transformer secondary control IED included in the circuit failure detection system of Figure 1. Figure 4 is a logic circuit diagram of the transformer secondary side circuit breaker opening of the transformer protection IED included in the circuit breaker failure detection system of Figure 1. FIG. 5 is a schematic block diagram of a blocking failure detection method according to one embodiment of the present invention. FIG. 6 is a schematic block diagram of a blocking failure detection system according to one embodiment of the present invention. Figure 7 is a schematic hardware structure diagram of the control unit of Figure 6. FIG. 8 is a schematic example of the operation process of a blocking failure detection system according to one embodiment of the present invention. FIG. 9 is a schematic example of another operation process of a blocking failure detection system according to one embodiment of the present invention. Specific details for implementing the invention

[0018] Embodiments of the present disclosure are described below with reference to the attached drawings so that those skilled in the art can easily implement them. However, the present disclosure may be embodied in various different forms and is not limited to the embodiments described herein. Furthermore, in order to clearly explain the present disclosure in the drawings, parts unrelated to the explanation have been omitted, and similar parts throughout the specification are denoted by similar reference numerals.

[0019] In the specification, when a part is described as "including" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components. Devices constituting a network may be implemented in hardware, software, or a combination of hardware and software.

[0020] Additionally, terms such as "...part," "...unit," and "...module" described in the specification refer to a unit that processes at least one function or operation, and this may be implemented in hardware, software, or a combination of hardware and software.

[0021] The devices described in one embodiment of the present invention are composed of hardware including at least one processor, a memory device, a communication device, etc., and a program that is executed in combination with the hardware is stored in a designated location. The hardware has a configuration and performance capable of executing a method according to one embodiment of the present invention. The program includes instructions that implement an operation method according to one embodiment of the present invention described with reference to the drawings, and executes one embodiment of the present invention in combination with hardware such as a processor and a memory device.

[0022] In this specification, "transmission or provision" may include not only direct transmission or provision but also indirect transmission or provision through other devices or by using an alternative route. Expressions described in the singular in this specification may be interpreted as singular or plural unless explicit expressions such as "one" or "singular" are used.

[0023] In this specification, terms including ordinal numbers, such as first, second, etc., may be used to describe various components, but these components are not limited by these terms. These terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the present disclosure, the first component may be named the second component, and similarly, the second component may be named the first component.

[0024] In the flowchart described with reference to the drawings in this specification, the order of operations may be changed, several operations may be merged or some operations may be divided, and certain operations may not be performed.

[0025] FIG. 1 schematically illustrates a power system diagram in which a blocking failure detection system according to one embodiment of the present invention operates. The power system diagram of FIG. 1 is merely for illustrating the present invention and is not limited thereto. Accordingly, the power system diagram of FIG. 1 can be modified differently.

[0026] As illustrated in FIG. 1, a circuit breaker (CB) and a relay are provided on the primary and secondary sides of the 23kV transformer, respectively. The circuit breaker failure protection panel is connected to the secondary side relay of the 23kV transformer and functions as a transformer secondary control IED. The distribution line protection IED is connected to each of the multiple distribution lines connected to the secondary side of the 23kV transformer via the T / L protection panel and the circuit breaker failure protection panel, and monitors each of the multiple distribution lines. Although not illustrated in FIG. 1, the 23kV transformer includes a transformer protection IED.

[0027] Intelligent electric devices (IEDs) are installed on 23kV transformers and multiple distribution lines connected thereto. The IEDs monitor the distribution lines in real time. The IEDs monitor the line voltage, line current, voltage fluctuation rate, reactive power, current imbalance, system frequency, system frequency fluctuation rate, energy consumption, circuit interruption status, protective relay operation status, and communication status of the distribution lines.

[0028] The IED detects a tripping failure of the 23kV transformer and, based on this, opens the secondary circuit breaker of the 23kV transformer. More specifically, the distribution line protection IED transmits whether each of the multiple distribution lines has failed to trip to the transformer secondary control IED. The transformer secondary control IED then determines whether there is an overall tripping failure based on these failures and transmits this to the transformer protection IED. The transformer protection IED determines whether to open the secondary circuit breaker of the 23kV transformer based on the determination of this overall tripping failure and the determination of the current element of the 23kV transformer. This will be explained in detail below through the logic circuit diagrams of FIGS. 2 to 4.

[0029] FIG. 2 shows a logic circuit diagram for verifying the interruption failure of a distribution line protection IED included in the interruption failure detection system of FIG. 1, FIG. 3 shows a logic circuit diagram for verifying the overall interruption failure of a transformer secondary control IED included in the interruption failure detection system of FIG. 1, and FIG. 4 shows a logic circuit diagram for opening the transformer secondary side circuit breaker of the transformer protection IED included in the interruption failure detection system of FIG. 1. The logic circuits of FIG. 2 to FIG. 4 are merely for illustrating the present invention and are not limited thereto. Accordingly, the logic circuit diagrams of FIG. 2 to FIG. 4 may be modified differently.

[0030] The output of the logic circuit of Fig. 2 is used as the input of the logic circuit of Fig. 3. Also, the output of the logic circuit of Fig. 3 is used as the input of the logic circuit of Fig. 4. This is explained in detail as follows.

[0031] The power line protection IED (100) is operated by the logic circuit of Fig. 2. The logic circuit of the power line protection IED (100) includes a first OR gate (110), a second OR gate (120), and a first AND gate (130). Accordingly, whether the blocking failed is output.

[0032] In the logic circuit of FIG. 2, a distribution line protection IED (100) is connected to each distribution line to monitor the distribution line (DL). FIG. 2 illustrates only the judgment method for the first distribution line, but in reality, multiple judgments are made for the second distribution line through the nth distribution line, corresponding to the number of distribution line protection IEDs (100). The distribution line protection IED (100) determines that an overcurrent has been detected in the distribution line when it detects an overcurrent in one or more of the OCR (Over Current Relay) and OCGR (Over Current Ground Relay) of the distribution line.

[0033] The OCR protects the power system by automatically interrupting the circuit when it detects an overcurrent. The OCR detects the current in the distribution line through a current transformer and compares the detected current with the set current configured in the OCR. Here, the set current is the maximum current flowing into the monitored circuit under normal operating conditions. The OCR operates when the detected current exceeds the set current. When the OCR operates, it protects the power system by opening the circuit breaker.

[0034] The OCGR is a relay that detects overcurrent and opens the circuit breaker, specifically detecting overcurrent caused by a ground fault. The OCGR is a current transformer installed at the neutral point and detects zero-sequence current generated by three-phase imbalance. The detected zero-sequence current is compared with the corrected ground fault current set in the OCGR. Here, the corrected ground fault current is the minimum zero-sequence current value flowing when a ground fault occurs. If the detected zero-sequence current exceeds the corrected ground fault current, the OCGR operates to open the circuit breaker and protect the power system.

[0035] In the logic circuit of Fig. 2, when an overcurrent is detected by OCR and OCGR, the state is set to '1', respectively. Then, the state of OCR and OCGR is input to the first OR gate (110). Therefore, when an overcurrent is detected by at least one of the relays, OCR and OCGR, the distribution line protection IED (100) determines that an overcurrent has been detected.

[0036] The state of the disconnecting switches (DS) connected to the distribution line is also considered. The disconnecting switches include a first disconnecting switch and a second disconnecting switch. The disconnecting switch has one of two states: disconnected or closed. If the disconnecting switch is in the closed state, it is set to '1', and if the disconnecting switch is in the open state, it is set to '0'. Each state is input to the second OR gate (120). If one or more of the first and second disconnecting switches are in the closed state, the distribution line protection IED (100) determines that the distribution line is energized. If both the first and second disconnecting switches are in the disconnected state, the distribution line protection IED (100) determines that the distribution line is de-energized. Next, the overcurrent state output and the distribution line state output are input to the first AND gate (130), and the first AND gate (130) outputs whether the distribution line has failed to disconnect. Indicates whether blocking failed by printing '1' if blocking failed and '0' if blocking did not fail.

[0037] The distribution line protection IED (100) determines whether the distribution line has failed to cut off based on the overcurrent of the distribution line and the energized / de-energized state of the distribution line. For example, if it is determined that the distribution line is in an overcurrent state and energized state, the distribution line protection IED (100) determines that the distribution line has failed to cut off. In other situations, it does not determine that the line has failed to cut off.

[0038] Next, the transformer secondary control IED (200) included in the secondary side of the 23kV transformer is operated by the logic circuit of FIG. 3. In the logic circuit of the transformer secondary control IED (200), the output of the distribution line protection IED (100) of FIG. 2 is input to the third OR gate (210). That is, the output of the distribution line protection IED (100) connected to each distribution line of FIG. 2, which is the failure of each distribution line to be cut off, is combined and input to the third OR gate (210). As a result, the combined failure of multiple distribution lines to be cut off is output.

[0039] The transformer secondary control IED (200) logic circuit takes as input whether the first to nth distribution lines failed to cut off. Then, these inputs are input to the third OR gate (210) to output whether the overall distribution lines failed to cut off.

[0040] That is, depending on whether there is a comprehensive failure to cut off, it can be determined that a failure to cut off has occurred in one or more of the distribution lines among the outputs of each distribution line protection IED (100). If it is determined that there is a comprehensive failure to cut off, set it to '1', and if it is not determined that there is a comprehensive failure to cut off, set it to '0'.

[0041] Next, the transformer protection IED (300) included in the 23kV transformer is operated by the logic circuit of FIG. 4. The transformer protection IED (300) inputs the current element and the overall failure of the distribution line, which are the outputs of the transformer secondary control IED (200) of FIG. 2, to the second AND gate (310). Then, the output of the second AND gate (310) is delayed by the delay unit (320) for a time set by the user. Depending on the output of the delay unit (320), it is determined whether the secondary side circuit breaker of the 23kV transformer is opened. If the output of the second AND gate (310) does not change for longer than the set time, the secondary side circuit breaker of the 23kV transformer is opened.

[0042] The delay unit (320) is provided to prevent malfunctions that may occur when a delay occurs due to the operation of an IED or the opening time of a circuit breaker, etc., in the event of a failure to cut off a 23kV transformer. The set operation delay time may be 0.2 seconds. This set operation delay time is determined by taking the cycle into account.

[0043] In a power system, a cycle represents one period of a specific current or voltage waveform. In cases such as setting the operating time of a protective relay, the setting time is indicated in cycle units, which is the time required to complete one period of a specific current or voltage waveform. A cycle is the reciprocal of the frequency. Since the frequency of current used in Korea is 60 Hz, one cycle corresponds to 1 / 60 of a second. Cycles are used for setting protective relays in power systems, designing relay systems, fault analysis, and determining system stability. These setting operating delay times are merely examples and may vary depending on the embodiment.

[0044] These cycles set thresholds to open circuit breakers via protective relays in the event of faults such as overcurrent, overvoltage, or ground faults, thereby preventing damage to equipment within the power system. Cycles are used for the overall design and operation of the relay system, as well as for identifying the cause, location, and severity of faults. Cycles serve as reference points that maintain system stability and prevent excessive voltage or current rises.

[0045] When a fault occurs in a distribution line, the distribution line protection IED (100) (shown in FIG. 2, hereinafter the same) detects the fault and takes 3 cycles to operate. After the distribution line protection IED (100) transmits an open signal to the circuit breaker, it takes 3 cycles to open the circuit breaker. Additionally, 6 cycles are added to account for the delay in the IED operation or the circuit breaker opening time. That is, a total of 12 cycles are required, and since 1 cycle is 1 / 60 of a second, the set operation delay time is 0.2 seconds. This set operation delay time is merely an example and can be varied in many ways.

[0046] The current element serves as an Over Current Breaker Failure (OCBF) element to establish the setting criteria for the relay. The operation of the OCBF element is configured to correct the relay when the transformer's operating current exceeds 150% of the transformer's maximum rated current. Additionally, the operating current of the OCBF element is matched to the operating current of the transformer backup protection relay. This minimizes mis-settings that may occur due to different operating currents.

[0047] More specifically, the operating current value of the overcurrent element for tripping failure verification is set to be determined as the fault current rather than the load current. Since the 23kV transformer does not have a tripping failure protection function, the backup protection relay eliminates tripping failure faults. Therefore, the operating current of the backup protection relay and the operating current of the overcurrent element for tripping failure verification are made identical.

[0048] As illustrated in FIGS. 2 to 4, a distribution line protection IED (100) connected to each of the multiple distribution lines outputs whether the circuit breaker fails for each of the multiple distribution lines. Next, the circuit breaker failure status for all of the multiple distribution lines output from each of the multiple IEDs is transmitted to a transformer secondary control IED (200) included in the secondary side of a 23kV transformer.

[0049] The transformer secondary control IED (200) outputs whether the entire distribution line being monitored has failed to cut off and transmits this to the transformer protection IED (300). If a failure to cut off occurs in the distribution line, the transformer secondary control IED (200) determines that a fault has occurred in the distribution line. Accordingly, the transformer secondary control IED (200) transmits a failure to cut off signal to the transformer protection IED (300).

[0050] The transformer protection IED (300) protects the power system by opening the secondary circuit breaker of the 23kV transformer when a fault is detected for a longer period than the set judgment delay time based on the circuit breaker failure signal transmitted from the transformer secondary control IED (200) and the current element.

[0051] FIG. 5 schematically illustrates a flowchart of a method for detecting a circuit breaker failure in a 23kV power system according to an embodiment of the present invention. The flowchart of the circuit breaker failure detection method in FIG. 5 is merely for illustrating the present invention and is not limited thereto. Accordingly, the flowchart of FIG. 5 may be modified differently.

[0052] The method for detecting a circuit breaker failure includes a step of determining whether one or more of the distribution lines among a plurality of distribution lines have failed to cut off (S10), a step of determining whether the entire distribution line has failed to cut off (S20), a step of determining whether the secondary side circuit breaker of a 23kV transformer has opened (S30), and a step of opening the secondary side circuit breaker of a 23kV transformer (S40). In addition, the method for detecting a circuit breaker failure may include other steps.

[0053] First, in step (S10), it is determined whether each of the multiple distribution lines has failed to cut off. If a failure to cut off occurs in one or more of the multiple distribution lines, the process proceeds to step (S20). In step (S20), it is determined whether the entire set of multiple distribution lines has failed to cut off. If it is determined that the entire set of multiple distribution lines has failed to cut off, the process proceeds to step (S40). In step (S30), it is determined whether to open the secondary circuit breaker of the 23kV transformer based on the determination in step (S20) and the current element of the 23kV transformer. Then, if it is determined to open the secondary circuit breaker of the 23kV transformer, the process moves to step (S40) and opens the secondary circuit breaker of the 23kV transformer. Unlike the case described above, if no circuit breaker failure occurs in multiple distribution lines in step (S10), or if a circuit breaker failure occurs in one or more distribution lines in step (S20) but it is not a total circuit breaker failure of the entire distribution line, or if there is no need to open the secondary side circuit breaker of the 23kV transformer in step (S30), all processes are terminated.

[0054] FIG. 6 schematically illustrates the block structure of a control system (1000) of a circuit breaker failure detection system for a 23kV power system according to one embodiment of the present invention. The control system (1000) of FIG. 6 is merely for illustrating the present invention and is not limited thereto. Accordingly, the control system of FIG. 6 may be modified differently.

[0055] Referring to FIG. 6, the control system (1000) includes a data collection unit (10), an input unit (20), an output unit (30), and a control unit (20). In addition, the control system (1000) may include other components.

[0056] The data collection unit (10) collects data from an external power system database (DB) for detecting and determining the failure of a 23kV power system interruption.

[0057] The power system database (DB) stores system operation data, instrumentation data, 23kV transformer data, 23kV distribution line data, protective relay data, system planning data, and system design data. System operation data includes protective relay data, system fault data, and weather data. Instrumentation data includes data for transformers, lines, power plants, and the entire system. 23kV transformer data includes high-voltage side voltage, low-voltage side voltage, current, frequency, power factor, temperature, and tap position. 23kV distribution line data includes voltage, current, frequency, active power, reactive power, and temperature. Protective relay data includes relay operation records, relay setpoints, and relay test results. Here, relay setpoints include data for overcurrent, overvoltage, ground fault, synchronization, and setpoints for each protective relay. System planning data includes system load forecast data, system investment planning data, and system operation optimization data. System design data includes system configuration data, system parameter data, maintenance data, and system stability analysis data. Here, system configuration data includes the location and capacity of power plants, substations, transmission lines, distribution lines, etc., as well as system connection configuration and topology data. System parameter data includes data such as line impedance, capacitance, receiveability, transformer characteristics, analysis of the impact of changes in system parameters, and relay setpoints. Maintenance data includes equipment inspection data, fault recovery data, and maintenance status data.

[0058] The data collection unit (10) collects data necessary to determine the detection of a circuit breaker failure in a 23kV power system from the power system database (DB). For example, the data collection unit (10) collects OCR data, OGCR data, disconnector status data, overcurrent element data for confirming circuit breaker failure for each distribution line.

[0059] The input unit (20) can be used as a means to change various parameters for determining the detection of a circuit breaker failure in a 23kV power system. That is, the user can input and change these parameters. For example, depending on the type of equipment or the surrounding environment, the user can input and change the set operation delay time when determining a circuit breaker failure or the overcurrent element for verifying a circuit breaker failure through the input unit (20).

[0060] The output unit (30) can display the control results of the control system (1000), etc., to the outside through a display, etc. For example, if it is determined that a failure to cut off a 23kV power system has been detected, the output unit (30) can display the point of failure to cut off, the magnitude of the overcurrent, the time to clear the fault, and whether there is a delay time, etc.

[0061] The control unit (40) controls the data collection unit (10), the input unit (20), and the output unit (30). The control unit (40) controls the circuit breaker failure detection system of the 23kV power system so that each step of the circuit breaker failure detection method of FIG. 5 proceeds. That is, the control unit (40) determines whether there is an overcurrent and whether the power is energized for each distribution line using the OCR data, OGCR data, and disconnector status data of each of the multiple distribution lines. The control unit (40) determines that there is a circuit breaker failure when the power is energized while an overcurrent is flowing in. The control unit (40) can determine whether there is a circuit breaker failure for each of the multiple distribution lines. In addition, the control unit (40) checks whether there is a circuit breaker failure for all distribution lines included in the system and determines whether a circuit breaker failure has occurred based on the entire system. If a circuit breaker failure has occurred based on the entire system, the overcurrent element correction criteria for checking the circuit breaker failure are checked, and if a current greater than the set criteria flows in, it can determine that there is a circuit breaker failure. If the control unit (40) determines that the circuit breaker has failed, and the circuit breaker failure condition persists for longer than a set time, the secondary circuit breaker of the 23kV transformer can be opened.

[0062] FIG. 7 schematically illustrates the hardware structure of the control unit (40) of FIG. 6. The hardware structure of the control unit (40) of FIG. 7 is merely for illustrative purposes of the present invention and is not limited thereto. Accordingly, the hardware structure of the control unit (40) of FIG. 7 can be modified differently.

[0063] Referring to FIG. 7, the control unit (40) may be implemented as at least one computing device and may execute a computer program containing instructions described to execute an operation according to one embodiment. The control unit (40) includes one or more processors (410), one or more storage (420), one or more memory (430), and one or more communication interfaces (440). Here, the processor (410) may be a microprocessor. These may be connected to each other via a bus. In addition, the control unit (40) may include hardware such as input devices and output devices. Furthermore, the control unit (40) may be equipped with various software, including an operating system capable of running a program. The method for detecting a failure to cut off a 23kV power system according to FIG. 5 described above can be performed using a microprocessor.

[0064] The processor (410) controls the operation of the blocking failure detection system. The processor (410) may be a various type of processor that processes instructions included in a program. For example, the processor (410) may be a CPU (Central Processing Unit), MPU (Micro Processor Unit), MCU (Micro Controller Unit), GPU (Graphic Processing Unit), etc. Storage (420) stores various data, programs, etc. required to execute an operation according to one embodiment. Memory (430) loads the corresponding program so that instructions described to execute an operation according to one embodiment are processed by the processor (410). For example, memory (430) may be ROM (read-only memory), RAM (random access memory), etc. The communication interface (440) is a wired / wireless communication module and can interact with an external database through a wired / wireless network.

[0065] FIG. 8 schematically illustrates the operation process of a blocking failure detection system according to one embodiment of the present invention. The single-line diagram of FIG. 8 is merely for illustrating the present invention and is not limited thereto. Accordingly, the single-line diagram of FIG. 8 may be modified differently.

[0066] FIG. 8 shows a state in which a circuit breaker failure detection system according to an embodiment of the present invention operates normally, and after a fault occurs in a 23kV power system, the circuit breaker operates and isolates only the faulty part from the power system. The 23kV power system includes a 23kV transformer, a first circuit breaker (CB) on its secondary side, and a first relay of a circuit breaker failure protection panel. The circuit breaker failure protection panel is installed between the 23kV transformer and the first circuit breaker. The 23kV transformer transmits power through a first distribution line and a second distribution line. A second circuit breaker and a third circuit breaker are installed on the first distribution line and the second distribution line, respectively. A second relay of the circuit breaker failure protection panel is installed on the secondary side of the second circuit breaker, and a third relay of the circuit breaker failure protection panel is also installed on the secondary side of the third circuit breaker. A fourth relay of the T / L protection panel is installed on the primary side of the second circuit breaker. When a fault occurs on the secondary side of the second circuit breaker, the T / L protection panel is activated by the fourth relay and transmits a tripping signal and a tripping failure (BFI) signal to the second circuit breaker and the tripping failure protection panel, respectively. Consequently, the second circuit breaker opens upon receiving the tripping signal, thereby isolating only the power system on the second circuit breaker side. As a result, the power system can be protected.

[0067] FIG. 9 schematically illustrates another operation process of a blocking failure detection system according to one embodiment of the present invention. The single-line diagram of FIG. 9 is merely for illustrating the present invention and is not limited thereto. Accordingly, the single-line diagram of FIG. 9 may be modified differently. Since the single-line diagram of FIG. 9 is identical to the single-line diagram of FIG. 8, a detailed description of the identical parts is omitted.

[0068] As illustrated in FIG. 9, an example can be given where the second circuit breaker fails to trip in step (S400). That is, the T / L protection panel does not operate, so the second circuit breaker does not open. In this case, since a fault current flows within the unisolated system, the trip failure protection panel operates in step (S500). In this case, to isolate the third distribution line from the second distribution line and to isolate the transformer from the second and third distribution lines, a circuit breaker opening signal is transmitted to the third circuit breaker and the second circuit breaker, respectively. Therefore, the first circuit breaker and the third circuit breaker open in step (S600). As a result, damage to the power system can be prevented. In other words, by using a trip failure detection system, even if some circuit breakers fail to trip, the spread of the fault to the entire power system can be prevented.

[0069] Although embodiments of the present disclosure have been described in detail above, the scope of the present disclosure is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concepts of the present disclosure as defined in the following claims also fall within the scope of the present disclosure. Explanation of the symbols

[0070] 10. Data Collection Unit 20. Input Unit 30. Output Unit 40. Control Unit 100. Distribution Line Protection IED 110. First OR Gate 120. Second OR Gate 130. First AND Gate 140. Whether blocking failed 200. Transformer Secondary Control IED 210. Third OR Gate 220. Whether comprehensive blocking failed 300. Transformer Protection IED 310. Second AND Gate 320. Delay section 410. Processor 420. Storage 430. Memory 440. Communication Interface DB. Power System Database D1. Whether the distribution line failed to cut off D2. Whether there is a failure of the combined interruption of multiple distribution lines

Claims

Claim 1 A circuit breaker failure detection system for a 23kV power system comprises a distribution line protection IED (intelligent electric device) connected to a plurality of distribution lines connected to the secondary side of a 23kV transformer and monitoring each of the plurality of distribution lines, a transformer secondary control IED installed on the secondary side of the 23kV transformer, and a transformer protection IED included in the 23kV transformer; wherein the distribution line protection IED transmits whether there is a circuit breaker failure of each of the plurality of distribution lines to the transformer secondary control IED; wherein the transformer secondary control IED determines whether there is an overall circuit breaker failure based on the determination of the overall circuit breaker failure and determines whether there is an overall circuit breaker failure based on the determination of the current element of the 23kV transformer and determines whether the secondary side circuit breaker of the 23kV transformer is opened; and wherein the distribution line protection IED determines, based on the current flowing into the distribution line and the status of a plurality of disconnectors installed on each of the plurality of distribution lines Detecting whether there is a failure to interrupt a distribution line, and if an overcurrent is detected by one or more relays among an OCR (Over Current Relay) and an OCGR (Over Current Ground Relay) installed on the distribution line, determining that an overcurrent has been detected in the distribution line, and if no overcurrent is detected by either the OCR or the OCGR, determining that an overcurrent has not been detected in the distribution line, wherein the plurality of disconnectors includes a first disconnector and a second disconnector, and if one or more of the first disconnector and the second disconnector are in an energized state, the distribution line protection IED determines that the distribution line is energized, and if both the first disconnector and the second disconnector are in an energized state, the distribution line protection IED determines that the distribution line is de-energized.A circuit breaker detection system wherein the distribution line protection IED determines whether the distribution line fails to trip based on the overcurrent of the distribution line and the energized or de-energized state of the distribution line, wherein the distribution line protection IED determines the distribution line as a circuit breaker failure only when the distribution line is in an overcurrent state and the distribution line is in an energized state, and does not determine the distribution line as a circuit breaker failure if one or more of the overcurrent state and the energized state of the distribution line are not satisfied, wherein the transformer protection IED determines the current element of the 23kV transformer based on the maximum rated current of the 23kV transformer, and wherein the transformer protection IED opens the secondary circuit breaker only when the same state is maintained even after a set operation delay time, and when a comprehensive circuit breaker failure is determined by the transformer secondary control IED, and the transformer protection IED detects a current of 150% or more of the maximum rated current. Claim 2 delete Claim 3 delete Claim 4 delete Claim 5 delete Claim 6 delete Claim 7 delete Claim 8 delete Claim 9 A circuit breaker failure detection system according to claim 1, wherein the transformer protection IED determines the current element of the 23kV transformer based on the maximum rated current of the 23kV transformer, and determines a comprehensive circuit breaker failure by the transformer secondary control IED, and if the transformer protection IED detects a current of 150% or more of the maximum rated current and the current of the 23kV transformer becomes less than 150% of the maximum rated current after a set operation delay time, the transformer protection IED does not open the secondary circuit breaker. Claim 10 A blocking failure detection system according to claim 1 or 9, wherein the set operation delay time is 0.2 seconds. Claim 11 A method for detecting a circuit breaker failure in a 23kV power system comprises, respectively, a distribution line protection IED connected to a plurality of distribution lines connected to the secondary side of a 23kV transformer in the 23kV power system and monitoring each of the plurality of distribution lines, a transformer secondary control IED installed on the secondary side of the 23kV transformer, and a transformer protection IED included in the 23kV transformer; a first step in which the distribution line protection IED transmits whether there is a circuit breaker failure of each of the plurality of distribution lines to the transformer secondary control IED; a second step in which the transformer secondary control IED determines whether there is an overall circuit breaker failure based on the determination of the circuit breaker failure and transmits the result to the transformer protection IED; and a third step in which the transformer protection IED determines whether to open the secondary side circuit breaker of the 23kV transformer based on the determination of the overall circuit breaker failure and the determination of the current element of the 23kV transformer, wherein the first step comprises the current flowing into the distribution line and a plurality of installed on each of the plurality of distribution lines The method comprises: a first-1 step of detecting whether the circuit breaker of the distribution line has failed to disconnect based on the status of the disconnectors; a first-2 step of determining that an overcurrent has been detected in the distribution line when an overcurrent is detected by one or more relays among the OCR and OCGR installed on the distribution line; and a first-3 step of determining that an overcurrent has not been detected in the distribution line when no overcurrent is detected by either the OCR or the OCGR, wherein in the first-1 step, the plurality of disconnectors includes a first disconnector and a second disconnector, and the first-1 step comprises: a step in which the distribution line protection IED determines that the distribution line is energized when one or more of the first disconnector and the second disconnector are in an energized state; and a step in which the distribution line protection IED determines that the distribution line is de-energized when both the first disconnector and the second disconnector are in an energized state.The distribution line protection IED includes a step of determining whether the distribution line has failed to cut off the distribution line based on the overcurrent of the distribution line and the energized or de-energized state of the distribution line, wherein the step of determining whether the distribution line has failed to cut off the distribution line includes: a step in which the distribution line protection IED determines the distribution line as having failed to cut off the distribution line only when the distribution line is in an overcurrent state and the distribution line is in an energized state; and a step in which the distribution line protection IED does not determine the distribution line as having failed to cut off the distribution line when one or more of the overcurrent state of the distribution line and the energized state of the distribution line are not satisfied, and the third step includes a 3-1 step in which the transformer protection IED determines the current element of the 23kV transformer based on the maximum rated current of the 23kV transformer, and if it is determined to be a comprehensive cut-off failure by the transformer secondary control IED and the transformer protection IED detects a current of 150% or more of the maximum rated current, a set A method for detecting circuit breaker failure comprising a 3-2 step in which the transformer protection IED opens the secondary circuit breaker only if the same state is maintained even after an operation delay time. Claim 12 delete Claim 13 delete Claim 14 delete Claim 15 delete Claim 16 delete Claim 17 delete Claim 18 delete Claim 19 A method for detecting a circuit breaker failure according to claim 11, wherein the third step comprises: a third-1 step in which the transformer protection IED determines the current element of the 23kV transformer according to the maximum rated current of the 23kV transformer; and a third-2 step in which, when a total circuit breaker failure is determined by the transformer secondary control IED, the transformer protection IED detects a current of 150% or more of the maximum rated current and the current of the 23kV transformer becomes less than 150% of the maximum rated current after a set operation delay time, the transformer protection IED does not open the secondary circuit breaker. Claim 20 A blocking failure detection method according to claim 11 or 19, wherein in step 3-2 above, the setting operation delay time is 0.2 seconds. Claim 21 A method for detecting a circuit breaker failure in a 23kV power system by a microprocessor comprises: a first step of determining whether each of a plurality of distribution lines connected to the secondary side of a 23kV transformer has failed to cut off; a second step of determining whether there is a comprehensive failure of the distribution lines based on the determination of whether there is a circuit breaker failure; and a third step of determining whether there is an open circuit breaker installed on the secondary side of the 23kV transformer based on the determination of whether there is a comprehensive failure of the distribution lines based on the determination of whether there is a circuit breaker failure in the second step and the current element of the 23kV transformer; in the third step, the open circuit breaker is determined based on the determination of whether there is a comprehensive failure of the distribution lines in the second step and the current element of the 23kV transformer; in the first step, a plurality of disconnectors are installed on each of the plurality of distribution lines, and the overcurrent status of the distribution lines and the status of the plurality of disconnectors are determined; the overcurrent status of the distribution lines is determined based on whether an overcurrent is detected by an OCR and an OCGR installed on the distribution lines, and if the OCR determines that an overcurrent is detected, '1' is output. If it is not determined that an overcurrent has been detected, '0' is output; if the OCGR determines that an overcurrent has been detected, '1' is output; if it is not determined that an overcurrent has been detected, '0' is output; the output of the OCR and the output of the OCGR are input to a first OR gate; each of the plurality of disconnectors outputs '1' if it is in an closed state and '0' if it is in an open state; the plurality of disconnectors includes a first disconnector and a second disconnector; the state of the first disconnector and the state of the second disconnector are input to a second OR gate; the outputs of the first OR gate and the second OR gate are input to a first AND gate to detect whether the distribution line has failed to cut off; the determination of the overall cutoff failure in the second stage is determined as an overall cutoff failure if one or more of the plurality of second distribution lines determine that the cutoff failure has occurred; and when determining the cutoff failure in the first stage, if it is determined that the cutoff failure has occurred Print '1',A method for detecting a trip failure, wherein '0' is output when it is determined that there is no trip failure, the output of the trip failure status is input to a third OR gate to determine whether there is a comprehensive trip failure in the second stage, the determination of whether there is a comprehensive trip failure in the second stage and the determination of the current element of the 23kV transformer in the third stage are input to a second AND gate, and the secondary circuit breaker is opened only when the output of the second AND gate persists for a set time or longer, and when determining the current element, the current element is set according to the maximum rated current of the 23kV transformer, and the current element is equal to the overcurrent time-delay operating current value of the backup protection relay of the 23kV transformer. Claim 22 delete Claim 23 delete Claim 24 delete Claim 25 delete Claim 26 delete Claim 27 delete Claim 28 delete Claim 29 A blocking failure detection method according to claim 21, wherein the judgment of comprehensive blocking failure is input to the second AND gate by setting it to '1' if it is determined to be a comprehensive blocking failure in the second step and '0' if it is not determined to be a comprehensive blocking failure. Claim 30 A method for detecting a tripping failure according to claim 29, wherein the current element judgment is set to '1' if the current detected by the 23kV transformer is greater than or equal to the overcurrent time-delay operating current value of the backup protection relay, and set to '0' if the current is less than the overcurrent time-delay operating current value of the backup protection relay, and input to the second AND gate.

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