A method and apparatus for diagnosing faults in an electrical circuit

Abstract

The application discloses a kind of fault diagnosis method and device of electric circuit, comprising: obtaining the current signal of the line interval of current transformer, voltage signal and at least two measurement and control devices Multiple first power signals and multiple second power signals;According to current signal and voltage signal, generate first test power signal and second test power signal;According to multiple first power signals and multiple second power signals, generate third test power signal and fourth test power signal;According to the relationship between first test power signal and third test power signal and the relationship between second test power signal and fourth test power signal Determine the working state of the electric circuit of current transformer.The fault diagnosis method provided by the application can avoid the protection misoperation of the electric circuit failure caused by refusal to move, and at the same time, through the programmed automatic detection of current loop, the cost of manual inspection can be reduced, and the efficiency of inspection can be improved.

Description

Technical Field

[0001] This invention relates to the field of circuit technology, and in particular to a method and apparatus for diagnosing faults in electrical circuits. Background Technology

[0002] In substation relay protection, measurement, and fault diagnosis, current loops play a crucial role. Daily operations frequently require verification of the values ​​and polarities of the current loops in each functional winding to check for open circuits and ensure correct polarity. However, during routine acceptance and inspections, due to varying skill levels among relay protection personnel, issues such as failing to detect incorrect current loop polarity or failing to restore current continuity after testing, leading to open circuits, have occurred. Several incidents involving current loop faults such as incorrect polarity and open circuits have already occurred, severely impacting the safe and reliable operation of power grid equipment. Summary of the Invention

[0003] This invention provides a method and apparatus for fault diagnosis of electrical circuits. By detecting faults in the line bays of substations, it avoids maloperation or failure of protection systems caused by current loop faults in operating bays. Automatic detection of electrical circuits reduces the cost of manual inspection, improves inspection efficiency, and reduces missed inspections due to skill limitations.

[0004] According to a first aspect of the present invention, a fault diagnosis method for an electrical circuit is provided, applied to a current transformer in a substation, the fault diagnosis method comprising:

[0005] Acquire the current signal, voltage signal, and multiple first power signals and multiple second power signals from at least two measurement and control devices in the line interval where the current transformer is located;

[0006] A first test power signal and a second test power signal are generated based on the current signal and the voltage signal;

[0007] A third test power signal and a fourth test power signal are generated based on a plurality of the first power signals and a plurality of the second power signals;

[0008] The operating state of the current transformer's circuit is determined based on the relationship between the first test power signal and the third test power signal, and the relationship between the second test power signal and the fourth test power signal; wherein the measurement and control device and the line interval are located on the same bus.

[0009] Optionally, before acquiring the current signal, voltage signal, and multiple first power signals and multiple second power signals of the line interval where the current transformer is located, the method further includes:

[0010] Obtain the bus-side disconnect switch position signal, circuit breaker position signal, and line voltage signal of the substation;

[0011] Determine the operating state of the equipment in the line interval according to the bus-side disconnect switch position signal, the circuit breaker position signal, and the line voltage signal.

[0012] Optionally, determining the operating state of the equipment in the line interval according to the bus-side disconnect switch position signal, the circuit breaker position signal, and the line voltage signal includes:

[0013] When the bus-side disconnect switch position signal, the circuit breaker position signal, and the line voltage signal meet the first preset condition, it is determined that the equipment in the line interval is in the operating state;

[0014] When the bus-side disconnect switch position signal, the circuit breaker position signal, and the line voltage signal do not meet the first preset condition, it is determined that the equipment in the line interval is in the non-operating state; wherein, the first preset condition includes that the bus-side disconnect switch position signal is in the closing state, the circuit breaker position signal is in the closing state, and the line voltage exceeds 30% of the phase voltage.

[0015] Optionally, generating the first test power signal and the second test power signal according to the current signal and the voltage signal includes:​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​

[0023] P 1h =-(P2+P3+……+P n ) (three)

[0024] Q 1h =-(Q2+Q3+……+Q) n ) (Four)

[0025] Among them, P 1h Q is the third test power signal of the measurement and control device. 1h P2 is the fourth test power signal of the measurement and control device, P3 is the first power signal of the second measurement and control device, Q2 is the second power signal of the second measurement and control device, and Q3 is the second power signal of the third measurement and control device; where n is a positive integer greater than 1.

[0026] Optionally, determining the operating state of the current transformer's circuit based on the relationship between the first test power signal and the third test power signal, and the relationship between the second test power signal and the fourth test power signal, includes:

[0027] When the relationship between the first test power signal and the third test power signal and the relationship between the second test power signal and the fourth test power signal both meet the second preset condition, the electrical circuit is determined to be in normal operating condition.

[0028] When the relationship between the first test power signal and the third test power signal and the relationship between the second test power signal and the fourth test power signal do not meet the second preset condition, the electrical circuit is determined to be in a fault state; wherein, the second preset condition includes that the values ​​and signs of the first test power signal and the third test power signal are consistent, and the values ​​and signs of the second test power signal and the fourth test power signal are consistent.

[0029] Optionally, when the relationship between the first test power signal and the third test power signal and the relationship between the second test power signal and the fourth test power signal do not meet the second preset condition, after determining that the electrical circuit is in a fault state, the following steps are taken:

[0030] An alarm message is generated based on the fault status and sent to the user terminal.

[0031] Optionally, the alarm information includes at least one of the following: voice reminder, buzzer reminder, and light reminder.

[0032] Optionally, the line bay includes one of the following: a line protection device, a line measuring device, a line metering device, and a fault recording device.

[0033] According to a second aspect of the present invention, a fault diagnosis device for an electrical circuit is provided, applied to a current transformer in a substation, the fault diagnosis device being used to perform a fault diagnosis method for an electrical circuit as described in any of the first aspects, the fault diagnosis device comprising:

[0034] The acquisition module is used to acquire the current signal, voltage signal, and multiple first power signals and multiple second power signals of at least two measurement and control devices in the line interval where the current transformer is located;

[0035] The calculation module is configured to generate a first test power signal and a second test power signal based on the current signal and the voltage signal; and to generate a third test power signal and a fourth test power signal based on a plurality of the first power signals and a plurality of the second power signals.

[0036] The determination module is used to determine the operating state of the current transformer's electrical circuit based on the relationship between the first test power signal and the third test power signal and the relationship between the second test power signal and the fourth test power signal; wherein the measurement and control device and the line interval are located on the same bus.

[0037] This invention discloses a fault diagnosis method for electrical circuits, applied to current transformers in substations. The fault diagnosis method includes: acquiring current signals, voltage signals, and multiple first power signals and multiple second power signals from at least two monitoring and control devices in the line bay where the current transformer is located; generating a first test power signal and a second test power signal based on the current and voltage signals; generating a third test power signal and a fourth test power signal based on the multiple first power signals and multiple second power signals; determining the operating state of the electrical circuit of the current transformer based on the relationship between the first and third test power signals and the relationship between the second and fourth test power signals; wherein the monitoring and control devices and the line bay are located on the same busbar. This invention provides a fault diagnosis method and apparatus for electrical circuits, which, by detecting current circuit faults in the line bays of substations, avoids protection maloperation or failure to operate caused by current circuit faults in operating bays. Automatic detection of electrical circuits reduces the cost of manual inspection, improves inspection efficiency, and reduces missed inspections due to skill limitations.

[0038] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a flowchart of a fault diagnosis method for an electrical circuit provided in an embodiment of the present invention;

[0041] Figure 2 This is a flowchart of another electrical circuit fault diagnosis method provided in an embodiment of the present invention;

[0042] Figure 3 This is a flowchart of another electrical circuit fault diagnosis method provided in an embodiment of the present invention;

[0043] Figure 4 This is a power calculation principle diagram provided in an embodiment of the present invention;

[0044] Figure 5 This is a flowchart of another electrical circuit fault diagnosis method provided in an embodiment of the present invention;

[0045] Figure 6 This is a flowchart of another electrical circuit fault diagnosis method provided in an embodiment of the present invention;

[0046] Figure 7 This is a flowchart of a fault diagnosis device for an electrical circuit provided in an embodiment of the present invention. Detailed Implementation

[0047] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0048] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0049] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0050] Figure 1 This is a flowchart of a fault diagnosis method for an electrical circuit provided in an embodiment of the present invention, for reference. Figure 1 The fault diagnosis method for electrical circuits provided in this embodiment of the invention is mainly applied to current transformers in substations. The fault diagnosis method includes:

[0051] S1. Obtain the current signal, voltage signal, and multiple first power signals and multiple second power signals from at least two measurement and control devices in the line interval where the current transformer is located.

[0052] Among them, a current transformer is an electrical device that works on the principle of electromagnetic induction and is mainly used to convert large currents into small currents for measurement and protection; a line bay is a specific area or bay within a substation used to connect external power lines and internal power distribution equipment; and a measurement and control device is a key device used to monitor and control the operation of the power system.

[0053] Specifically, the current signal, voltage signal, and multiple first power signals and multiple second power signals of at least two measurement and control devices in the line bay where the current transformer is located in the substation are acquired. For example, the first power signal is active power and the second power signal is reactive power.

[0054] S2. Generate the first test power signal and the second test power signal based on the current signal and the voltage signal.

[0055] Specifically, power flow calculation refers to a calculation method that calculates the distribution of active power, reactive power, and voltage in a power grid under given power system network topology, component parameters, and generation and load parameters. Based on the current and voltage signals obtained in step S1 above, a first test power signal and a second test power signal are generated through power flow calculation. The first test power signal can be active power, and the second test power signal can be reactive power.

[0056] S3. Generate a third test power signal and a fourth test power signal based on multiple first power signals and multiple second power signals.

[0057] Specifically, Kirchhoff's laws state that at any given moment, the sum of the currents flowing into any node is equal to the sum of the currents flowing out of that node, and in any closed loop, the algebraic sum of the voltages across all segments is always zero. Based on these laws, the third and fourth test power signals are determined using Kirchhoff's laws based on multiple first power signals (i.e., active power) and multiple second power signals (i.e., reactive power) obtained by multiple measurement and control devices. For example, the third test power signal is the active power signal tested by the measurement and control device, and the fourth test power signal is the reactive power signal tested by the measurement and control device.

[0058] S4. Determine the operating state of the current transformer's circuit based on the relationship between the first test power signal and the third test power signal, and the relationship between the second test power signal and the fourth test power signal.

[0059] Specifically, the first test power signal is compared with the third test power signal, that is, the first test power signal (test active power signal) on the line bay is compared with the third test power signal (test active power signal) determined on the measurement and control device, and the second test power signal (test reactive power signal) on the line bay is compared with the fourth test power signal (test reactive power signal) determined on the measurement and control device. In other words, the active power on the line bay is compared with the active power on the measurement and control device, and the reactive power on the line bay is compared with the reactive power on the measurement and control device, so as to determine the working state of the current transformer's circuit. For example, if the active power on the line bay matches the value and sign of the active power on the monitoring and control device, and the reactive power on the line bay also matches the value and sign of the reactive power on the monitoring and control device, then the current transformer's circuit is determined to be in normal operating condition. If the active power on the line bay differs from the value or sign of the active power on the monitoring and control device, or if the reactive power on the line bay differs from the value or sign of the reactive power on the monitoring and control device, then the current transformer's circuit is determined to be in a fault condition. The monitoring and control device and the line bay are located on the same busbar.

[0060] The circuit fault diagnosis method provided in this invention determines the circuit fault state of the current transformer by comparing the power signals on the line bay and the power signals on the monitoring and control device, thus avoiding maloperation or failure to operate the protection system due to current circuit faults in the operating bay. By automatically detecting the circuit, the cost of manual inspection can be reduced, the efficiency of inspection can be improved, and the number of missed inspections due to skill limitations can be reduced.

[0061] Based on the above embodiments of the invention, the embodiments of the present invention further refine the steps prior to acquiring the current signal, voltage signal, and multiple first power signals and multiple second power signals of at least two measurement and control devices in the line interval where the current transformer is located. Figure 2 This is a flowchart of another electrical circuit fault diagnosis method provided in an embodiment of the present invention, for reference. Figure 2 The fault diagnosis method for electrical circuits provided in this embodiment of the invention includes:

[0062] S21. Obtain the busbar side disconnector position signal, switch position signal, and line voltage signal of the substation.

[0063] The main function of the busbar in a substation is to collect, distribute, and transmit electrical energy. It achieves efficient power transmission by introducing high-voltage power from generators, transformers, or other power supply equipment to low-voltage equipment, or by aggregating the power from low-voltage equipment.

[0064] Specifically, the system acquires the busbar-side disconnector position signal, switch position signal, and line voltage signal of the substation. The busbar-side disconnector position signal includes both closed and open states, and the switch position signal includes both closed and open states.

[0065] S22. Determine the operating status of the equipment in the line bay based on the busbar-side disconnector position signal, switch position signal, and line voltage signal.

[0066] Specifically, the operating status of the equipment in the line bay is determined based on the position signal of the disconnector on the bus side of the substation, the position signal of the switch, and the line voltage signal determined in step S21 above. The current transformer circuit will only be monitored when the equipment in the line bay is in operation, thereby improving the monitoring efficiency.

[0067] S23. Obtain the current signal, voltage signal, and multiple first power signals and multiple second power signals from at least two measurement and control devices in the line interval where the current transformer is located.

[0068] S24. Generate a first test power signal and a second test power signal based on the current signal and the voltage signal.

[0069] S25. Generate a third test power signal and a fourth test power signal based on multiple first power signals and multiple second power signals.

[0070] S26. Determine the operating state of the current transformer's circuit based on the relationship between the first test power signal and the third test power signal, and the relationship between the second test power signal and the fourth test power signal.

[0071] Based on the above embodiments, this invention further refines the method for determining the operating status of line bays based on bus-side disconnector position signals, switch position signals, and line voltage signals. Figure 3 This is a flowchart of another electrical circuit fault diagnosis method provided in an embodiment of the present invention, for reference. Figure 3 The fault diagnosis method for electrical circuits provided in this embodiment of the invention includes:

[0072] S31. Obtain the busbar side disconnector position signal, switch position signal, and line voltage signal of the substation.

[0073] S32. Determine whether the busbar-side disconnector position signal, switch position signal, and line voltage signal meet the first preset condition.

[0074] The bus-side disconnector position signal, switch position signal, and line voltage signal obtained in step S31 are compared with the first preset conditions. If the first preset conditions are met, step S33 is executed; if the first preset conditions are not met, step S38 is executed. The first preset conditions include the bus-side disconnector position signal being in the closed state, the switch position signal being in the closed state, and the line voltage exceeding 30% of the phase voltage.

[0075] S33. When the busbar side disconnector position signal, switch position signal and line voltage signal meet the first preset condition, it is determined that the equipment in the line bay is in operation.

[0076] Specifically, when the busbar-side disconnector position signal is in the closed state, the switch position signal is in the closed state, and the line voltage signal exceeds 30% of the phase voltage, the equipment in the line bay is determined to be in operation. It can be understood that these three conditions must be met simultaneously for the first preset condition to be satisfied.

[0077] S38. When the busbar side disconnector position signal, switch position signal and line voltage signal do not meet the first preset condition, it is determined that the equipment in the line bay is in an inactive state.

[0078] Specifically, when the busbar-side disconnector position signal is open, or the switch position signal is open, or the line voltage signal does not exceed 30% of the phase voltage, it is determined that the equipment in the line bay is not in operation. The equipment not in operation may include equipment under maintenance during power outages and hot standby equipment.

[0079] Based on the above embodiments, the present invention further refines the generation of the first test power signal and the second test power signal according to the current signal and the voltage signal. Figure 4 This is a power calculation schematic diagram provided in an embodiment of the present invention, for reference. Figure 4 The first test power signal and the second test power signal are generated based on the current signal and the voltage signal, including:

[0080] The first test power signal and the second test power signal are calculated using formulas (I) and (II):

[0081] P 1j =UIcosθ (a)

[0082] Q 1j =UIsinθ (2)

[0083] Among them, P 1j U is the first test power signal of the interval, I is the voltage signal of the interval, θ is the current signal of the interval, and θ is the power factor angle.

[0084] Specifically, the active and reactive power of the line bay where the current transformer is located is calculated based on the acquired current and voltage signals.

[0085] Optionally, a third test power signal and a fourth test power signal are generated based on multiple first power signals and multiple second power signals, including:

[0086] Record multiple first power signals as P1 to P2. n Record multiple second power signals as Q1 to Q2. n ;

[0087] The third and fourth test power signals are calculated using formulas (III) and (IV):

[0088] P 1h =-(P2+P3+……+P n ) (three)

[0089] Q 1h =-(Q2+Q3+……+Q) n ) (Four)

[0090] Among them, P 1h Q is the third test power signal of the measurement and control device. 1h P2 is the fourth test power signal of the measurement and control device, P3 is the first power signal of the second measurement and control device, Q2 is the second power signal of the second measurement and control device, and Q3 is the second power signal of the third measurement and control device; where n is a positive integer greater than 1.

[0091] Specifically, the test power signals of multiple measurement and control devices are calculated separately. For example, there are three measurement and control devices. The active power and reactive power of each measurement and control device are calculated separately and named P1, P2, P3 and Q1, Q2, Q3 respectively. The third test power signal is obtained by calculating the third test power signal through the above formulas (III) and (IV). The principle of formulas (III) and (IV) is Kirchhoff's law, which is common knowledge and will not be elaborated here.

[0092] Based on the above embodiments, this invention further refines the determination of the operating state of the current transformer's circuit according to the relationship between the first test power signal and the third test power signal, and the relationship between the second test power signal and the fourth test power signal. Figure 5 This is a flowchart of another electrical circuit fault diagnosis method provided in an embodiment of the present invention, for reference. Figure 5 The fault diagnosis method for electrical circuits provided in this embodiment of the invention includes:

[0093] S41. Obtain the current signal, voltage signal, and multiple first power signals and multiple second power signals of at least two measurement and control devices in the line interval where the current transformer is located.

[0094] S42. Generate a first test power signal and a second test power signal based on the current signal and the voltage signal.

[0095] S43. Generate a third test power signal and a fourth test power signal based on multiple first power signals and multiple second power signals.

[0096] S44. Compare the relationship between the first test power signal and the third test power signal with the second preset condition; compare the relationship between the second test power signal and the fourth test power signal with the second preset condition; if both meet the second preset condition, proceed to step S45; if the second preset condition is not met, proceed to step S46, wherein the second preset condition includes that the values ​​and signs of the first test power signal and the third test power signal are consistent, and that the values ​​and signs of the second test power signal and the fourth test power signal are consistent.

[0097] S45. When the relationship between the first test power signal and the third test power signal and the relationship between the second test power signal and the fourth test power signal both meet the second preset condition, the circuit is determined to be in normal operating condition.

[0098] Specifically, when the relationship between the first test power signal and the third test power signal and the relationship between the second test power signal and the fourth test power signal both meet the second preset condition, it can be understood that the values ​​and signs of the first test power signal and the third test power signal are the same, and the values ​​and signs of the second test power signal and the fourth test power signal are the same, the current transformer's circuit is determined to be in normal operating condition.

[0099] S46. When the relationship between the first test power signal and the third test power signal and the relationship between the second test power signal and the fourth test power signal do not meet the second preset condition, the circuit is determined to be in a fault state.

[0100] Specifically, when the relationship between the first test power signal and the third test power signal and the relationship between the second test power signal and the fourth test power signal do not meet the second preset condition, it can be understood that if the value and sign of the first test power signal and the third test power signal are different, or if the value and sign of the second test power signal and the fourth test power signal are different, the current transformer circuit is determined to be in a fault state.

[0101] Based on the above embodiments, the present invention further refines the determination that the circuit is in a fault state when the relationship between the first test power signal and the third test power signal, and the relationship between the second test power signal and the fourth test power signal, do not meet the second preset condition. Figure 6 This is a flowchart of another electrical circuit fault diagnosis method provided in an embodiment of the present invention, for reference. Figure 6 The fault diagnosis method for electrical circuits provided in this embodiment of the invention includes:

[0102] S51. Obtain the current signal, voltage signal, and multiple first power signals and multiple second power signals of at least two measurement and control devices in the line interval where the current transformer is located.

[0103] S52. Generate a first test power signal and a second test power signal based on the current signal and the voltage signal.

[0104] S53. Generate a third test power signal and a fourth test power signal based on multiple first power signals and multiple second power signals.

[0105] S54. Compare the relationship between the first test power signal and the third test power signal with the second preset condition; compare the relationship between the second test power signal and the fourth test power signal with the second preset condition.

[0106] S56. When the relationship between the first test power signal and the third test power signal and the relationship between the second test power signal and the fourth test power signal do not meet the second preset condition, the circuit is determined to be in a fault state.

[0107] S57. Generate alarm information based on the fault status and send it to the user terminal.

[0108] Specifically, when step S56 determines that the current transformer's circuit is in a fault state, an alarm message is generated based on the fault state information and sent to the user terminal to remind staff to carry out maintenance.

[0109] Optionally, the alarm information may include at least one of the following: voice alert, buzzer alert, and light alert.

[0110] Specifically, for example, a buzzer may be included as an audible alert, and an illuminated alert may be included as an illuminating diode.

[0111] Optionally, the line bay may include one of the following: line protection device, line measuring device, line metering device, and fault recording device.

[0112] Specifically, line protection devices, line measuring devices, line metering devices, and fault recording devices in line bays can all perform fault diagnosis of electrical circuits using the same principle, which will not be elaborated here. Protection devices are mainly used for the protection of power systems. When a short circuit, overload, or other fault occurs in the power system, the current signal of the protection group will be transmitted to the protection device (such as a relay) to trigger the corresponding protection action, such as tripping, to prevent equipment damage or the escalation of the accident.

[0113] Measuring devices are mainly used for real-time monitoring and control of power systems. The current signals from the measuring group are transmitted to measuring instruments (such as ammeters, wattmeters, etc.) to display system parameters such as current and power in real time.

[0114] Metering devices are mainly used for measuring electrical energy in power systems. The current signal from the metering group is transmitted to the electricity meter, which is used to calculate and record the system's electrical energy consumption, providing a basis for electricity billing.

[0115] Figure 7 This is a block flowchart of an electrical circuit fault diagnosis device provided in an embodiment of the present invention, for reference. Figure 7 Based on the same inventive concept, this invention provides a fault diagnosis device for an electrical circuit, applied to a current transformer in a substation. The fault diagnosis device is used to execute the fault diagnosis method for the electrical circuit described in the above-described embodiments. The fault diagnosis device includes:

[0116] The acquisition module 1 is used to acquire the current signal, voltage signal, and multiple first power signals and multiple second power signals of at least two measurement and control devices in the line interval where the current transformer is located.

[0117] The calculation module 2 is used to generate a first test power signal and a second test power signal based on the current signal and the voltage signal; and to generate a third test power signal and a fourth test power signal based on multiple first power signals and multiple second power signals.

[0118] The determination module 3 is used to determine the operating state of the current transformer's electrical circuit based on the relationship between the first test power signal and the third test power signal, and the relationship between the second test power signal and the fourth test power signal; wherein the measurement and control device and the line bay are located on the same bus.

[0119] The fault diagnosis device for an electrical circuit provided in this embodiment of the invention can achieve the same technical effect as the fault diagnosis method for an electrical circuit provided in any of the above embodiments of the invention, and will not be described in detail here.

[0120] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method of diagnosing a failure of an electric circuit, characterized by, The application relates to a current transformer applied to a transformer substation, and a fault diagnosis method. Obtaining current signals and voltage signals of a line interval in which the current transformer is located and n first power signals and n second power signals of at least two measurement and control devices; Generating first test power signals and second test power signals according to the current signals and the voltage signals; Generating third test power signals and fourth test power signals according to n first power signals and n second power signals; Determining the working state of an electric loop of the current transformer according to the relationship between the first test power signals and the third test power signals and the relationship between the second test power signals and the fourth test power signals; wherein the measurement and control devices and the line interval are located on the same bus. Generating first test power signals and second test power signals according to the current signals and the voltage signals, comprising: The first test power signals and the second test power signals are calculated through formulas (one) and (two): P 1j = UI cos θ (I) Q 1j = UI sin θ (two) where P 1j is the first test power signal of the interval, U is the voltage signal of the interval, I is the current signal of the interval, and Θ is the power factor angle. Generating third test power signals and fourth test power signals according to n first power signals and n second power signals, comprising: n first power signals P1~Pn are recorded n n second power signals Q1~Qn are recorded n ​ The third test power signals and the fourth test power signals are calculated through formulas (three) and (four): P 1h = - (P2+ P3+... + P n ) (three) Q 1h = - (Q2+ Q3+... + Q n ) (four) wherein P 1h is a third test power signal of the control device, Q 1h is a fourth test power signal of the control device, P2 is a first power signal of a second control device, P3 is a first power signal of a third control device, Q2 is a second power signal of the second control device, and Q3 is a second power signal of the third control device; wherein n is a positive integer greater than 1. Determining the working state of an electric loop of the current transformer according to the relationship between the first test power signals and the third test power signals and the relationship between the second test power signals and the fourth test power signals, comprising: When the relationship between the first test power signals and the third test power signals and the relationship between the second test power signals and the fourth test power signals both satisfy a second preset condition, it is determined that the electric loop is in a normal running working state; When the relationship between the first test power signals and the third test power signals and the relationship between the second test power signals and the fourth test power signals do not satisfy the second preset condition, it is determined that the electric loop is in a fault state; wherein the second preset condition comprises that the values and signs of the first test power signals and the third test power signals are consistent, and the values and signs of the second test power signals and the fourth test power signals are consistent.

2. The method of fault diagnosis of an electrical circuit according to claim 1, characterized in that, Before obtaining the current signals and voltage signals of the line interval in which the current transformer is located and n first power signals and n second power signals of at least two measurement and control devices, the method further comprises: Obtaining bus side knife switch position signals, switch position signals and line voltage signals of the transformer substation; Determining the device working state of the line interval according to the bus side knife switch position signals, the switch position signals and the line voltage signals.

3. The method of fault diagnosis of an electrical circuit according to claim 2, characterized in that, Determining the device working state of the line interval according to the bus side knife switch position signals, the switch position signals and the line voltage signals, comprising: When the bus side knife switch position signals, the switch position signals and the line voltage signals satisfy a first preset condition, it is determined that the device of the line interval is in a running state; When the bus side knife switch position signal, the switch position signal and the line voltage signal do not satisfy the first preset condition, it is determined that the line interval device is in a non-operating state; wherein the first preset condition includes that the bus side knife switch position signal is in a closed state, the switch position signal is in a closed state and the line voltage exceeds 30% of the phase voltage.

4. The method of fault diagnosis of an electrical circuit according to claim 1, wherein, When the relationship between the first test power signal and the third test power signal and the relationship between the second test power signal and the fourth test power signal do not satisfy the second preset condition, it is determined that the electric circuit is in a fault state, including: Generating an alarm information according to the fault state and sending it to the user end.

5. The method of fault diagnosis of an electrical circuit according to claim 4, characterized in that, The alarm information includes at least one of the following: voice reminder, buzzer reminder and light reminder.

6. The method of fault diagnosis of an electrical circuit according to claim 1, wherein, The line interval includes one of the line protection device, line measurement device, line metering device and fault recording device.

7. A failure diagnosing device for an electric circuit, characterized by comprising: The current transformer applied to the substation, the fault diagnosis device is used to execute the fault diagnosis method of the electric circuit in any one of claims 1 to 6, and the fault diagnosis device comprises: An acquisition module is used to acquire the current signal, voltage signal and n first power signals and n second power signals of at least two measurement and control devices of the line interval where the current transformer is located; A calculation module is used to generate a first test power signal and a second test power signal according to the current signal and the voltage signal; and generate a third test power signal and a fourth test power signal according to n first power signals and n second power signals; A determination module is used to determine the working state of the electric circuit of the current transformer according to the relationship between the first test power signal and the third test power signal and the relationship between the second test power signal and the fourth test power signal; wherein the measurement and control device and the line interval are located on the same bus.

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