A dual-core symmetrical phase-shifting transformer composite differential protection device and method thereof

Abstract

The present application relates to the field of transformer differential protection, especially to a kind of double-core symmetric phase-shifting transformer composite differential protection device and method, on the basis of analyzing its magnetic circuit structure, according to physical principles such as Kirchhoff's current law, electromagnetic induction law, the symmetric double-core phase-shifting transformer protection scheme is established, only the current of transformer input and output needs to be collected, through a set of devices, the internal fault of series transformer and excitation transformer and the short-circuit fault of lead between them can be identified, thereby the problems of compact internal structure of double-core phase-shifting transformer, complex fault characteristics and difficult to collect internal current are overcome, the number of current transformers installed is reduced, the economy is optimized, a kind of engineering practical value technical method is provided for the differential protection application of double-core symmetric phase-shifting transformer, a theoretical basis is laid for further analyzing the protection scheme of phase-shifting transformer of this structure, and it has guiding significance in engineering application and popularization.

Description

Technical Field

[0001] This invention relates to the field of transformer differential protection, and in particular to a composite differential protection device and method for a dual-core symmetrical phase-shifting transformer. Background Technology

[0002] A high proportion of renewable energy grid connection brings a series of problems to the power system, thus requiring the power system to have a high degree of flexibility in regulation. In a power system, without any control methods, the power flow will follow a distribution inversely proportional to impedance, i.e., a natural power distribution. This natural power distribution may lead to irrational power flow distribution along lines, affecting the security and economy of the power supply. Therefore, power flow control methods are needed to regulate the power transmitted along the lines.

[0003] A two-core phase-shifting transformer is a power flow regulating device that adjusts the phase of current and voltage in transmission lines, thereby regulating the power flow. A two-core phase-shifting transformer consists of a series transformer and an excitation transformer. Its neutral point is grounded, and the excitation section is not directly connected to the system. Utilizing these characteristics, during grid loop closing operations, the phase-shifting transformer can make the voltage and phase on both sides of the loop closing switch nearly identical, achieving very small or even zero-impact closing, thus enabling uninterrupted power supply to the load.

[0004] The differential protection configuration of a phase-shifting transformer is closely related to its primary structure, as its series transformer and excitation transformer are housed in the same enclosure, resulting in a complex structure. Compared to conventional transformers, the installation location and number of current transformers (CTs) are limited by the compact primary structure of the phase-shifting transformer, which affects the engineering configuration and implementation of differential protection.

[0005] In order to provide more effective protection for symmetrical two-core phase-shifting transformers, it is necessary to propose new protection schemes. Summary of the Invention

[0006] This invention addresses the aforementioned dual-core phase-shifting transformer by proposing a composite differential protection device and method for a dual-core symmetrical phase-shifting transformer, particularly relating to such a device and method, the method comprising:

[0007] The input and output currents of the dual-core symmetrical phase-shifting transformer are collected, including the primary input and output currents of each phase series transformer, and the excitation transformer turns ratio is identified online.

[0008] Based on the magnetic circuit coupling and current balance relationship of the dual-core symmetrical phase-shifting transformer, the protection action criteria of the dual-core symmetrical phase-shifting transformer are constructed.

[0009] Based on the protection action criteria, the fault of the dual-core symmetrical phase-shifting transformer is determined.

[0010] Preferably, current transformers are configured at the primary input and output terminals of the series transformer, with a total of two sets.

[0011] Preferably, the acquisition of the input and output currents of the dual-core symmetrical phase-shifting transformer includes the primary input and output currents of each phase series transformer, and the online identification of the excitation transformer turns ratio includes:

[0012] Let ports S and L be the input and output terminals of the two-core phase-shifting transformer, respectively. and These are the primary input and output currents of the A-phase series transformer, respectively, and also the primary input and output currents of the A-phase of the two-core phase-shifting transformer; and These are the primary input and output currents of the B-phase series transformer, respectively, and also the primary input and output currents of the B-phase of the two-core phase-shifting transformer; and These are the primary input and output currents of the C-phase series transformer, respectively, and also the primary input and output currents of the C-phase of the two-core phase-shifting transformer; This refers to the secondary current of the A-phase series transformer. This refers to the secondary current of the B-phase series transformer. This refers to the secondary current of the C-phase series transformer. and These are the currents on the primary and secondary sides of the A-phase excitation transformer, respectively. and These are the currents on the primary and secondary sides of the B-phase excitation transformer, respectively. and These represent the primary and secondary currents of the C-phase excitation transformer, respectively; the turns ratio of both the secondary and primary windings of the series transformer is... The turns ratio of the primary winding to the secondary winding of the excitation transformer is: .

[0013] Preferably, the protection action criterion includes the following steps:

[0014] Step 1: The secondary side of the series transformer is delta-connected and has a direct circuit connection to the secondary side of the excitation transformer. According to Kirchhoff's current law, the current relationship between the secondary sides of the series transformer and the excitation transformer is established by writing the equation:

[0015] (1)

[0016] (2)

[0017] (3)

[0018] Step 2: Based on the magnetic flux balance of the series transformer, write the current relationship equations on both sides of the series transformer:

[0019] (4)

[0020] (5)

[0021] (6)

[0022] Step 3: Based on the magnetic flux balance of the excitation transformer, list the formula for the current relationship across the excitation transformer:

[0023] (7)

[0024] (8)

[0025] (9)

[0026] Step 4: Considering the direct circuit connection between the primary side of the series transformer and the primary side of the excitation transformer, based on Kirchhoff's current law, list the current relationship formula between the primary sides of the series transformer and the excitation transformer:

[0027] (10)

[0028] (11)

[0029] (12)

[0030] Step 5: Combine equations (1), (4), (7), and (10) to eliminate the negative equations. , , , , From the external current, we can obtain:

[0031] (13)

[0032] Similarly, by combining equations (2), (5), (8), (11) and equations (3), (6), (9), (12) respectively, we can obtain:

[0033] (14)

[0034] (15)

[0035] Step 6: According to equations (13), (14), and (15), the differential current calculation formula is obtained:

[0036] (16)

[0037] Step 7: According to equation (16), the composite differential protection criterion for the dual-core symmetrical phase-shifting transformer is obtained.

[0038] Preferably, the composite differential protection of the dual-core symmetrical phase-shifting transformer is determined as follows:

[0039] (17)

[0040] in This represents the protection setting. If it satisfies equation (17), the protection will operate; otherwise, the protection will not operate.

[0041] Preferably, equations (1) to (3) reflect grounding short-circuit faults in the leads between the secondary side of the series transformer and the excitation transformer; equations (4) to (6) reflect inter-turn faults in the windings of the series transformer; equations (7) to (9) reflect inter-turn faults in the windings of the excitation transformer by identifying the transformer ratio online; and equations (10) to (12) reflect short-circuit faults in the leads between the primary side of the series transformer and the excitation transformer.

[0042] Preferably, the three-phase differential current calculation formula (16) simultaneously reflects the inter-turn faults of the windings of the series transformer, the inter-turn faults of the windings of the excitation transformer, the short-circuit faults of the primary leads of the series transformer and the excitation transformer, and the short-circuit faults of the secondary leads; the protection criterion (17) can effectively identify the above-mentioned faults.

[0043] This invention also discloses a composite differential protection device for a dual-core symmetrical phase-shifting transformer, characterized in that:

[0044] Current measurement module: Collects the input and output currents of the dual-core symmetrical phase-shifting transformer, including the primary input and output currents of each phase series transformer, and identifies the excitation transformer turns ratio online;

[0045] The protection action criterion construction module constructs the protection action criterion of the dual-core symmetrical phase-shifting transformer based on the magnetic circuit coupling and current balance relationship of the dual-core symmetrical phase-shifting transformer.

[0046] Fault determination module: Based on the protection action criteria, it determines the fault of the dual-core symmetrical phase-shifting transformer.

[0047] Preferably, the dual-core symmetrical phase-shifting transformer composite differential protection device includes a dual-core symmetrical phase-shifting transformer, a current transformer, a microprocessor-based differential protection device, and a circuit breaker trip coil. The dual-core symmetrical phase-shifting transformer can identify the excitation transformer turns ratio online. Current transformers CT1, CT2, CT3, CT4, CT5, and CT6 are used to collect the input and output currents on the primary side of the series transformer, respectively. , , , , and The excitation transformer turns ratio and the acquired current are both input into the microprocessor-based differential protection device; the microprocessor-based differential protection device is used to construct and calculate the differential current. , and Further construct the protection action criteria for the dual-core symmetrical phase-shifting transformer body, and finally output signal commands; the circuit breaker fault coil is used to receive the commands output by the microcomputer protection device, and control the protection action according to the commands.

[0048] The present invention also discloses a non-volatile storage medium, the non-volatile storage medium including a stored program, wherein the program, when running, controls the device where the non-volatile storage medium is located to execute a composite differential protection method for a dual-core symmetrical phase-shifting transformer.

[0049] The present invention also discloses an electronic device comprising a processor and a memory; the memory stores computer-readable instructions, and the processor is used to execute the computer-readable instructions, wherein the computer-readable instructions, when executed, perform a dual-core symmetrical phase-shifting transformer composite differential protection device.

[0050] The beneficial effects of this invention are as follows: It proposes a protection scheme based on Kirchhoff's current law and electromagnetic induction law for symmetrical two-core phase-shifting transformers. It only requires the acquisition of the current on the input and output sides of the phase-shifting transformer. A single device can detect internal faults in the series transformer and the excitation transformer, as well as short-circuit faults in the leads between them. This overcomes the problems of compact internal structure, complex fault characteristics, and difficulty in acquiring internal current in two-core phase-shifting transformers. At the same time, it reduces the number of current transformers. It lays a theoretical foundation for further analysis of protection schemes for this type of phase-shifting transformer and has guiding significance for its engineering application and promotion. Attached Figure Description

[0051] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the 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.

[0052] Figure 1This is a flowchart illustrating a composite differential protection method for a dual-core symmetrical phase-shifting transformer provided in an embodiment of the present invention.

[0053] Figure 2 This is a structural diagram of a symmetrical two-core phase-shifting transformer.

[0054] Figure 3 This is a composite differential protection configuration for one phase of a symmetrical dual-core phase-shifting transformer according to an embodiment of the present invention;

[0055] Figure 4 This is a structural diagram of a symmetrical dual-core phase-shifting transformer composite differential protection fault determination system according to an embodiment of the present invention; Detailed Implementation

[0056] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 are within the scope of protection of the present invention.

[0057] The purpose of this invention is to provide a protection configuration scheme for a symmetrical dual-core phase-shifting transformer. Based on the analysis of its magnetic circuit structure, this symmetrical dual-core phase-shifting transformer protection scheme is established according to physical principles such as Kirchhoff's current law and electromagnetic induction law. The feature is that it only needs to collect the current on the input side and output side of the transformer, and a set of devices can identify internal faults of the series transformer and the excitation transformer as well as short-circuit faults of the leads between them.

[0058] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0059] Figure 1 This is a flowchart illustrating a composite differential protection method for a dual-core symmetrical phase-shifting transformer according to an embodiment of the present invention. The method includes the following steps:

[0060] Step 101: Collect the input and output currents of the dual-core symmetrical phase-shifting transformer, including the primary input and output currents of each phase series transformer, and identify the excitation transformer turns ratio online;

[0061] Define physical quantities and their positive directions as follows: Figure 2 As shown, ports S and L are denoted as the input and output terminals of a two-core phase-shifting transformer, respectively, and the various current phasors are... The reference directions are marked on the diagram, where and These are the primary input and output currents of the A-phase series transformer, respectively, and also the primary input and output currents of the A-phase of the two-core phase-shifting transformer; and These are the primary input and output currents of the B-phase series transformer, respectively, and also the primary input and output currents of the B-phase of the two-core phase-shifting transformer; and These are the primary input and output currents of the C-phase series transformer, respectively, and also the primary input and output currents of the C-phase of the two-core phase-shifting transformer; This refers to the secondary current of the A-phase series transformer. This refers to the secondary current of the B-phase series transformer. This refers to the secondary current of the C-phase series transformer. and These are the currents on the primary and secondary sides of the A-phase excitation transformer, respectively. and These are the currents on the primary and secondary sides of the B-phase excitation transformer, respectively. and These represent the primary and secondary currents of the C-phase excitation transformer, respectively; the turns ratio of both the secondary and primary windings of the series transformer is... The turns ratio of the primary winding to the secondary winding of the excitation transformer is: ;

[0062] Current sampling , , , , and Online recognition .

[0063] Step 102: Based on the magnetic circuit coupling and current balance relationship of the dual-core symmetrical phase-shifting transformer, construct the protection action criteria for the dual-core symmetrical phase-shifting transformer body;

[0064] Step 102 specifically includes:

[0065] The secondary side of the series transformer is delta-connected and has a direct circuit connection to the secondary side of the excitation transformer. Based on Kirchhoff's current law, the current relationship between the secondary sides of the series transformer and the excitation transformer is established using equations:

[0066] (1)

[0067] (2)

[0068] (3)

[0069] Based on the magnetic flux balance of a series transformer, write the equations relating the currents on both sides of the series transformer:

[0070] (4)

[0071] (5)

[0072] (6)

[0073] Based on the magnetic flux balance of the excitation transformer, the formula for the current relationship across the excitation transformer is derived:

[0074] (7)

[0075] (8)

[0076] (9)

[0077] Considering the direct circuit connection between the primary side of the series transformer and the primary side of the excitation transformer, based on Kirchhoff's current law, the current relationship between the primary sides of the series transformer and the excitation transformer is formulated as follows:

[0078] (10)

[0079] (11)

[0080] (12)

[0081] By combining equations (1), (4), (7), and (10), we can eliminate the... , , , , From the external current, we can obtain:

[0082] (13)

[0083] Similarly, by combining equations (2), (5), (8), (11) and equations (3), (6), (9), (12) respectively, we can obtain:

[0084] (14)

[0085] (15)

[0086] Based on equations (13), (14), and (15), the formula for calculating differential current is obtained:

[0087] (16)

[0088] According to equation (16), the criterion for composite differential protection of a dual-core symmetrical phase-shifting transformer is obtained, where Indicates the protection setting:

[0089] (17)

[0090] Equations (1) to (3) reflect grounding short-circuit faults in the leads between the secondary sides of the series transformer and the excitation transformer; equations (4) to (6) reflect inter-turn faults in the windings of the series transformer; equations (7) to (9) reflect inter-turn faults in the windings of the excitation transformer by identifying the transformer ratio online; equations (10) to (12) reflect short-circuit faults in the leads between the primary sides of the series transformer and the excitation transformer; the three-phase differential current calculation formula (16) can simultaneously reflect inter-turn faults in the windings of the series transformer, inter-turn faults in the windings of the excitation transformer, short-circuit faults in the leads on the primary side of the series transformer and the excitation transformer, and short-circuit faults in the leads on the secondary side; the protection criterion (17) effectively identifies the above faults.

[0091] With differential current For example, differential current (1) can reflect the ground fault of the lead wire between the secondary side of the BC phase series transformer and the A phase excitation transformer. Furthermore, substituting equations (5) and (6) into equation (1), the resulting differential current (18) can simultaneously reflect the ground fault of the lead wire between the secondary side of the BC phase series transformer and the A phase excitation transformer, as well as the inter-turn fault of the BC phase series transformer:

[0092] (18)

[0093] Furthermore, substituting equation (7) into equation (18), the resulting differential current (19) can simultaneously reflect the ground fault of the lead between the secondary sides of the BC-phase series transformer and the A-phase excitation transformer, the inter-turn fault of the BC-phase series transformer, and the inter-turn fault of the A-phase excitation transformer:

[0094] (20)

[0095] Furthermore, substituting equation (10) into equation (19), the resulting differential current (20) can simultaneously reflect the ground fault of the lead between the secondary sides of the BC-phase series transformer and the A-phase excitation transformer, the inter-turn fault of the BC-phase series transformer, the inter-turn fault of the A-phase excitation transformer, and the short-circuit fault of the lead between the primary sides of the A-phase series transformer and the excitation transformer:

[0096] (20)

[0097] Therefore, differential current It can simultaneously reflect the grounding short circuit fault of the lead wire between the secondary side of the BC phase series transformer and the A phase excitation transformer, the inter-turn fault of the BC phase series transformer, the inter-turn fault of the A phase excitation transformer, and the short circuit fault of the lead wire between the primary side of the A phase series transformer and the excitation transformer. The differential current formula (16) can simultaneously reflect the winding inter-turn fault of the three-phase series transformer, the winding inter-turn fault of the excitation transformer, the short circuit fault of the lead wire on the primary side of the series transformer and the excitation transformer, and the short circuit fault of the lead wire on the secondary side. The protection criterion (17) can effectively identify the above faults.

[0098] Step 103: Based on the protection action criteria, determine the fault of the dual-core symmetrical phase-shifting transformer.

[0099] Step 103 specifically includes:

[0100] Based on the protection action criterion obtained in step 102 ,in This represents the protection setting. If the above formula is satisfied, then the differential current... , , If one or more phases exceed the set value, the protection will operate; otherwise, the protection will be locked and will not operate.

[0101] This invention also provides a system for determining faults in a symmetrical two-core phase-shifting transformer, such as... Figure 4 As shown, the system includes:

[0102] The current measurement module 401 is used to collect the current of the symmetrical dual-core phase-shifting transformer, the current including the input and output currents of the primary side of the series transformer.

[0103] The start-up criterion construction module 402 is used to construct the protection action criterion based on the magnetic circuit coupling and current balance relationship of the dual-core symmetrical phase-shifting transformer.

[0104] The fault determination module 403 is used to determine the fault of the dual-core symmetrical phase-shifting transformer based on the composite differential protection criteria of the dual-core symmetrical phase-shifting transformer.

[0105] The current measurement module 401 specifically includes:

[0106] Through such Figure 3 CT1, CT2, CT3, CT4, CT5, and CT6, as shown, respectively collect the input and output currents on the primary side of the series transformer. , , , , and Online identification of excitation transformer turns ratio At this point, the flow into the primary winding of the series transformer is defined as the positive direction.

[0107] The startup criterion construction module 402 specifically includes:

[0108] Based on the data obtained from module 402 and the nameplate parameters of the phase-shifting transformer, the differential current is constructed and calculated using microcomputer protection software. , and as follows:

[0109]

[0110] The fault diagnosis module 403 specifically includes:

[0111] Differential current , , If one or more of the values ​​exceed the set value, the protection action criterion is met. ,in If the protection setting is specified, it indicates that a fault has occurred in the phase-shifting transformer, and the microcomputer protection device outputs a trip command, causing the protection to operate; otherwise, the protection is locked and does not operate.

[0112] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the claims of this application.

[0113] The successful development of the composite differential protection device and method for a dual-core symmetrical phase-shifting transformer proposed in this invention not only overcomes the problems of compact internal structure, complex fault characteristics, and difficulty in collecting internal current of dual-core phase-shifting transformers, but also reduces the number of current transformers required. This is of great significance for promoting the theoretical research and engineering application of phase-shifting transformer protection.

Claims

1. A composite differential protection method for a dual-core symmetrical phase-shifting transformer, characterized in that: The input and output currents of the dual-core symmetrical phase-shifting transformer are collected, including the primary input and output currents of each phase series transformer, and the excitation transformer turns ratio is identified online. Based on the magnetic circuit coupling and current balance relationship of the dual-core symmetrical phase-shifting transformer, the protection action criterion of the dual-core symmetrical phase-shifting transformer is constructed. Based on the protection action criteria, the fault of the dual-core symmetrical phase-shifting transformer is determined; The acquisition of the input and output currents of the dual-core symmetrical phase-shifting transformer includes the primary input and output currents of each phase series transformer. Online identification of the excitation transformer turns ratio includes: Let ports S and L be the input and output terminals of the two-core phase-shifting transformer, respectively. and These are the primary input and output currents of the A-phase series transformer, respectively, and also the primary input and output currents of the A-phase of the two-core phase-shifting transformer; and These are the primary input and output currents of the B-phase series transformer, respectively, and also the primary input and output currents of the B-phase of the two-core phase-shifting transformer; and These are the primary input and output currents of the C-phase series transformer, respectively, and also the primary input and output currents of the C-phase of the two-core phase-shifting transformer; This refers to the secondary current of the A-phase series transformer. This refers to the secondary current of the B-phase series transformer. This refers to the secondary current of the C-phase series transformer. and These are the currents on the primary and secondary sides of the A-phase excitation transformer, respectively. and These are the currents on the primary and secondary sides of the B-phase excitation transformer, respectively. and These represent the primary and secondary currents of the C-phase excitation transformer, respectively; the turns ratio of both the secondary and primary windings of the series transformer is... The turns ratio of the primary winding to the secondary winding of the excitation transformer is: ; The protection action criterion includes the following steps: Step 1: The secondary side of the series transformer is connected in a delta configuration and has a direct circuit connection to the secondary side of the excitation transformer. According to Kirchhoff's current law, the current relationship between the secondary sides of the series transformer and the excitation transformer is established by writing the equations: （1） （2） （3） Step 2: Based on the magnetic flux balance of the series transformer, write the current relationship equations on both sides of the series transformer: （4） （5） （6） Step 3: Based on the magnetic flux balance of the excitation transformer, list the formula for the current relationship across the excitation transformer: （7） （8） （9） Step 4: Considering the direct circuit connection between the primary side of the series transformer and the primary side of the excitation transformer, based on Kirchhoff's current law, list the current relationship formula between the primary sides of the series transformer and the excitation transformer: （10） （11） （12） Step 5: Combine equations (1), (4), (7), and (10) to eliminate the negative equations. , , , , External current: （13） Similarly, combining equations (2), (5), (8), (11) and equations (3), (6), (9), (12): （14） （15） Step 6: According to equations (13), (14), and (15), the differential current calculation formula is obtained: （16） Step 7: According to equation (16), the criterion for composite differential protection of dual-core symmetrical phase-shifting transformer is obtained.

2. The composite differential protection method for a dual-core symmetrical phase-shifting transformer according to claim 1, characterized in that: Current transformers are configured at the input and output terminals of the primary side of the series transformer.

3. The composite differential protection method for a dual-core symmetrical phase-shifting transformer according to claim 1, characterized in that: The composite differential protection for the dual-core symmetrical phase-shifting transformer is determined as follows: （17） in This represents the protection setting. If it satisfies equation (17), the protection will operate; otherwise, the protection will not operate.

4. The composite differential protection method for a dual-core symmetrical phase-shifting transformer according to claim 3, characterized in that: Equations (1) to (3) reflect the grounding short-circuit fault of the lead wire between the secondary side of the series transformer and the excitation transformer; Equations (4) to (6) reflect the winding inter-turn fault of the series transformer; Equations (7) to (9) reflect the winding inter-turn fault of the excitation transformer by identifying the transformer ratio online; Equations (10) to (12) reflect the short-circuit fault of the lead wire between the primary side of the series transformer and the excitation transformer.

5. The composite differential protection method for a dual-core symmetrical phase-shifting transformer according to claim 3, characterized in that: The differential current calculation formula (16) simultaneously reflects the inter-turn faults of the windings of the series transformer, the inter-turn faults of the windings of the excitation transformer, the short-circuit faults of the primary leads of the series transformer and the excitation transformer, and the short-circuit faults of the secondary leads; the protection criterion (17) effectively identifies the above-mentioned faults.

6. A composite differential protection device for a dual-core symmetrical phase-shifting transformer, used to execute the composite differential protection method for a dual-core symmetrical phase-shifting transformer as described in any one of claims 1 to 5, characterized in that: This includes a dual-core symmetrical phase-shifting transformer, current transformer, microprocessor-based differential protection device, and circuit breaker trip coil; among which, the dual-core symmetrical phase-shifting transformer provides online identification of the excitation transformer turns ratio. ; Current transformers CT1, CT2, CT3, CT4, CT5, and CT6 are used to collect the primary input and output currents of a three-phase series transformer, respectively. , , , , and The excitation transformer turns ratio and the collected current are both input into the microcomputer differential protection device; Microcomputer-based differential protection devices are used to construct and calculate differential current. , and The protection action criteria for the dual-core symmetrical phase-shifting transformer body are constructed, and a signal command is ultimately output. The circuit breaker trip coil is used to receive commands output by the microprocessor protection device and control the protection action according to the commands.

7. A non-volatile storage medium, characterized in that: The non-volatile storage medium includes a stored program, wherein the program, when running, controls the device where the non-volatile storage medium is located to execute the method of claim 1.

8. An electronic device, characterized in that, It includes a processor and a memory; the memory stores computer-readable instructions, and the processor is used to execute the computer-readable instructions, wherein the computer-readable instructions, when executed, perform the method of claim 1.

Images