A substation long distance control loop and control method

Abstract

This invention discloses a long-distance control loop and method for substations, belonging to the field of power system technology. It includes a substation-side control unit, a power plant-side control unit, and two independent, redundantly configured first and second remote signal transmission units. The substation-side control unit has a main transformer control and interlocking loop, and the power plant-side control unit has a switchgear control and interlocking loop. Each of the two remote signal transmission units contains corresponding substation-side and power plant-side signal devices, which are bidirectionally connected via dedicated optical fiber communication links. The signal output terminal of the substation-side control unit is connected to the two substation-side signal devices, and its output terminal is connected to the power plant-side control unit. The signal output terminal of the power plant-side control unit is connected to the two power plant-side signal devices, and its output terminal is connected to the substation-side control unit, achieving bidirectional control, improving the reliability of the control loop, and ensuring the safe and reliable operation of the power system.

Description

Technical Field

[0001] This invention belongs to the field of power system technology, specifically relating to a long-distance control loop and control method for substations. Background Technology

[0002] The 750kV substation uses a line transformer connection. No circuit breaker is installed on the high-voltage side outgoing line of the 750kV transformer. The 750kV outgoing line connects to the 750kV distribution area of ​​the power plant on the opposite side, approximately 1 kilometer away. The 750kV distribution area on the power plant side uses a one-and-a-half-circuit breaker connection. In this arrangement, due to space and other objective constraints, the main transformer protection of the 750kV substation is located in the relay compartment on the substation side, while the circuit breaker protection on the power plant side is located in the relay compartment on the power plant side. The main transformer protection output and circuits such as circuit breaker failure tripping are interconnected using long control cables. In this configuration, the cable core has a large distributed capacitance to ground, making it easier for interference signals to enter the protection device through the long cable. Furthermore, the fault caused by the distributed capacitance of the long cable is random, potentially interfering with the main transformer protection tripping of the 750kV substation and the 750kV circuit breaker failure tripping on the power plant side, causing abnormal equipment operation and even malfunctioning outputs of the circuits connected to the long cable.

[0003] See Figure 1 The diagram shows the relative layout of the substation and power plant. The 750kV substation uses a line transformer connection, and the high-voltage side outgoing line of the 750kV transformer does not have a circuit breaker. The 750kV outgoing line connects to the 750kV distribution area of ​​the power plant on the opposite side, approximately 1 kilometer away. The 750kV distribution area on the power plant side uses a one-and-a-half-circuit breaker connection. Under this layout, according to the existing design, the large distributed capacitance to ground in the long cable control circuit may interfere with the high-voltage side tripping of the 750kV substation main transformer protection, the main transformer air-cooling control circuit, the main transformer fire control circuit, the power plant side 750kV circuit breaker failure interlocking circuit, and the electrical interlocking circuit between the substation and the power plant, potentially causing malfunctions in the devices or circuits. Therefore, alternative design schemes need to be considered to prevent interference signals from entering the protection devices through the long cable and causing incorrect operation, ensuring the safe and effective operation of the equipment.

[0004] The high-voltage outgoing lines of the 750kV substation's transformer units lack circuit breakers and connect to the 750kV distribution area of ​​the opposite power plant, approximately 1 kilometer away. Under this arrangement, the existing design uses long-distance control cables to implement protection outputs, circuit breaker failure tripping, and air-cooled and fire-fighting control circuits. However, the large distributed capacitance to ground of these long control cables makes it easy for interference signals to enter the protection devices, potentially causing malfunctions. This technology results in low control circuit reliability and negatively impacts the stable operation of the power grid. Summary of the Invention

[0005] The purpose of this invention is to overcome the problem of maloperation of the output relay of the protection device due to the influence of the distributed capacitance of long cables when the long-distance control loop design is used in substations, and to propose a long-distance control loop and control method for substations.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a long-distance control loop for a substation, including a substation-side control unit, a power plant-side control unit, a first remote signal transmission unit, and a second remote signal transmission unit; the first remote signal transmission unit and the second remote signal transmission unit are mutually independent and redundantly configured. The substation-side control unit is equipped with control and interlocking circuits for the main transformer, while the power plant-side control unit is equipped with control and interlocking circuits for switchgear. The first remote signal transmission unit includes a first substation-side signal device and a first power plant-side signal device. The first substation-side signal device and the first power plant-side signal device are bidirectionally connected via a first dedicated optical fiber communication link. The second remote signal transmission unit includes a signal device on the second substation side and a signal device on the second power plant side. The signal device on the second substation side and the signal device on the second power plant side are bidirectionally connected via a second dedicated optical fiber communication link. The signal output terminals of the substation-side control unit are respectively connected to the signal input terminals of the first substation-side signal device and the second substation-side signal device. The signal output terminals of the first substation-side signal device and the second substation-side signal device are respectively connected to the control and interlocking circuit input terminals of the power plant-side control unit. The signal output terminals of the power plant-side control unit are respectively connected to the signal input terminals of the first power plant-side signal device and the second power plant-side signal device. The signal output terminals of the first power plant-side signal device and the second power plant-side signal device are respectively connected to the control and interlocking circuit input terminals of the substation-side control unit.

[0007] Furthermore, the first dedicated optical fiber communication link and the second dedicated optical fiber communication link are independent dedicated single-mode armored optical cable communication links.

[0008] Furthermore, the power supply, signal input circuit, signal output circuit, and communication link of the first remote signal transmission unit and the second remote signal transmission unit are all physically isolated from each other.

[0009] Furthermore, the substation-side control unit includes a main transformer protection device, a main transformer-side actuator, a substation-side switchgear, and a substation-side electrical interlocking circuit; The signal output terminals of the substation-side control unit include the action output contacts of the main transformer protection device and the position feedback contacts of the substation-side switchgear. The input terminals of the control and interlocking circuits of the substation-side control unit include the input terminals of the control circuits of the actuators on the main transformer side and the input terminals of the electrical interlocking circuits on the substation side.

[0010] Furthermore, the main transformer protection device includes a first main transformer electrical quantity protection device, a second main transformer electrical quantity protection device, and a main transformer non-electrical quantity protection device; the first main transformer electrical quantity protection device and the second main transformer electrical quantity protection device are mutually independent with dual redundancy configuration; the main transformer non-electrical quantity protection device is a single set configuration. The operation output contacts of the first main transformer power protection device are only connected to the signal input terminal of the signal device on the first substation side, and the operation output contacts of the second main transformer power protection device are only connected to the signal input terminal of the signal device on the second substation side. The operation output contacts of the non-electrical quantity protection device of the main transformer are respectively connected to the signal input terminals of the signal device on the first substation side and the signal input terminals of the signal device on the second substation side.

[0011] Furthermore, the main transformer side actuators include circuit breakers on each side of the main transformer, air-cooled control devices for the main transformer, and fire-fighting control devices for the main transformer; The tripping circuit input terminals of the circuit breakers on each side of the main transformer, the control circuit input terminals of the air-cooled control device of the main transformer, and the control circuit input terminals of the fire-fighting control device of the main transformer are respectively connected to the signal output terminals of the first power plant side signal device and the second power plant side signal device. The control circuits of the main transformer air-cooling control device and the main transformer fire-fighting control device are all connected in series with the normally closed position contacts of the power plant side high-voltage circuit breaker, which are transmitted through the first power plant side signal device and the second power plant side signal device.

[0012] Furthermore, the power plant-side control unit includes a high-voltage circuit breaker, power plant-side switchgear, circuit breaker protection device, circuit breaker control cabinet, and power plant-side electrical interlocking circuit; The signal output terminals of the power plant-side control unit include the operation output contacts of the circuit breaker protection device, the position feedback contacts of the high-voltage circuit breaker, and the position feedback contacts of the power plant-side switchgear. The input terminals of the control and interlocking circuits of the power plant side control unit include the trip control circuit input terminal of the circuit breaker control cabinet and the input terminal of the power plant side electrical interlocking circuit; The failure action output contacts of the circuit breaker protection device are respectively connected to the signal input terminals of the first power plant side signal device and the second power plant side signal device; The signal output terminals of the first substation-side signaling device and the second substation-side signaling device are respectively connected to the input terminal of the failure tripping circuit of the main transformer protection device.

[0013] Furthermore, the position feedback contacts of the substation-side switchgear are transmitted via the first substation-side signaling device, the first dedicated optical fiber communication link, and the first power plant-side signaling device, and then connected to the input terminal of the power plant-side electrical interlocking circuit. The position feedback contacts of the power plant-side switchgear are transmitted through the first power plant-side signaling device, the first dedicated optical fiber communication link, and the first substation-side signaling device, and then connected to the input terminal of the substation-side electrical interlocking circuit. The second remote signal transmission unit is synchronously configured with the first remote signal transmission unit to form a bidirectional position signal transmission and interlocking circuit, thus forming a dualized cross-station electrical interlocking circuit.

[0014] Furthermore, the substation-side switchgear includes a substation-side disconnector and a substation-side grounding switch, and the power plant-side switchgear includes a power plant-side disconnector and a power plant-side grounding switch. The normally closed contact of the substation-side grounding switch is connected to the electrical interlocking circuit of the power plant-side disconnecting switch. The normally closed contact of the power plant-side grounding switch is connected to the electrical interlocking circuit of the substation-side disconnecting switch. The normally closed contact of the power plant-side disconnecting switch is connected to the electrical interlocking circuit of the substation-side grounding switch, forming a cross-station five-prevention interlocking circuit.

[0015] Secondly, the present invention provides a long-distance control method for substations, comprising the following steps: Perform remote control operations from the substation side to the power plant side: The control signals output from the signal output terminal of the substation-side control unit are connected to the signal input terminals of the first substation-side signal device and the second substation-side signal device, respectively. The two control signals are transmitted to the first power plant-side signal device and the second power plant-side signal device via the first dedicated optical fiber communication link and the second dedicated optical fiber communication link, respectively. The two control signals output from the signal output terminals of the first power plant-side signal device and the second power plant-side signal device are connected to the control and interlocking circuit input terminals of the power plant-side control unit, respectively. The power plant-side switchgear is controlled and interlocked through the dual redundant signal. Perform remote control operations from the power plant side to the substation side: The control signals output from the power plant-side control unit are connected to the signal input terminals of the first power plant-side signaling device and the second power plant-side signaling device, respectively. The two control signals are transmitted to the first substation-side signaling device and the second substation-side signaling device via the first dedicated optical fiber communication link and the second dedicated optical fiber communication link, respectively. The two control signals output from the signal output terminals of the first substation-side signaling device and the second substation-side signaling device are connected to the control and interlocking circuit input terminals of the substation-side control unit, respectively. The substation-side main transformer protection is controlled and interlocked through the dual redundant signal.

[0016] Compared with the prior art, the present invention has the following beneficial technical effects: This invention proposes a long-distance control loop for substations. It employs a remote signal transmission device to convert electrical signals into optical signals, and uses a dedicated optical fiber direct connection to enable information exchange between the remote signal transmission devices on the substation and power plant sides. This completes the design scheme for the 750kV substation main transformer protection trip output, main transformer air-cooling control loop, main transformer fire control loop, 750kV circuit breaker failure tripping loop on the power plant side, and electrical interlocking loop between the substation and the power plant. This improves the reliability of the control loop and ensures the safe and reliable operation of the power system.

[0017] Furthermore, the high-voltage side outgoing lines of the 750kV substation transformer group are not equipped with circuit breakers and are connected to the 750kV distribution equipment area of ​​the power plant on the opposite side, which is approximately 1 kilometer away. To avoid interference caused by the large distributed capacitance to ground of the long cable control circuit, which could lead to malfunctions of the control circuits such as the high-voltage side tripping of the 750kV substation main transformer protection, the main transformer air-cooling control circuit, the main transformer fire control circuit, the power plant-side 750kV circuit breaker failure tripping, and the electrical interlocking circuit between the substation and the power plant, this invention proposes a design scheme for using a remote signal transmission device to complete information interaction when there are long-distance control circuits in the substation. This scheme enables the design of the 750kV substation main transformer protection tripping output, the main transformer air-cooling control circuit, the main transformer fire control circuit, the power plant-side 750kV circuit breaker failure tripping, and the interlocking circuit between the substation and the power plant. This improves the reliability of the control circuits and ensures the safe and reliable operation of the power system. Attached Figure Description

[0018] The accompanying drawings are provided to further understand the invention and constitute a part of this invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0019] Figure 1 This is a diagram showing the relative layout of the substation and the power plant.

[0020] Figure 2 This is a schematic diagram of the circuit logic of the remote signaling device between the substation and the power plant in a long-distance control circuit of a substation, as described in one embodiment. Detailed Implementation

[0021] 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 of the present invention. 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.

[0022] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0024] 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.

[0025] Explanation of related terms Control circuit: An electrical circuit consisting of control switches, relays, signal devices, DC power supplies and connecting lines, used to transmit and execute "opening" and "closing" commands for remote or local operation of equipment such as circuit breakers and disconnect switches.

[0026] Remote signal transmission device: An electrical or electronic device specifically designed for the reliable and real-time transmission of switching signals, status signals, alarm signals, and control commands between different locations.

[0027] Example 1 A long-distance control loop for a substation includes a substation-side control unit, a power plant-side control unit, a first remote signal transmission unit, and a second remote signal transmission unit. The first and second remote signal transmission units are independently configured with redundancy. The substation-side control unit is equipped with a control and interlocking circuit for the main transformer, and the power plant-side control unit is equipped with a control and interlocking circuit for switchgear. The first remote signal transmission unit includes a first substation-side signal device and a first power plant-side signal device, which are bidirectionally connected via a first dedicated optical fiber communication link. The second remote signal transmission unit includes a second substation-side signal device and a second... The power plant-side signaling device and the second substation-side signaling device are bidirectionally connected via a second dedicated optical fiber communication link. The signal output terminals of the substation-side control unit are respectively connected to the signal input terminals of the first substation-side signaling device and the second substation-side signaling device. The signal output terminals of the first substation-side signaling device and the second substation-side signaling device are respectively connected to the control and interlocking circuit input terminals of the power plant-side control unit. The signal output terminals of the power plant-side control unit are respectively connected to the signal input terminals of the first power plant-side signaling device and the second power plant-side signaling device. The signal output terminals of the first power plant-side signaling device and the second power plant-side signaling device are respectively connected to the control and interlocking circuit input terminals of the substation-side control unit.

[0028] This embodiment uses dedicated optical fiber communication to replace traditional long control cables, enabling bidirectional signal interaction between the substation and power plant sides, and completing core functions such as protection tripping, equipment control, and anti-misoperation interlocking, while meeting the reliability requirements of dual redundancy in the power system.

[0029] The following description, in conjunction with the accompanying drawings, further explains a long-distance control loop for a substation according to the present invention: This embodiment is divided into two main areas: the substation side and the power plant side. There is no direct cable connection between the two sides; bidirectional signal transmission is achieved only through dedicated optical fibers. A completely independent dual-system design is adopted (corresponding to the power system protection dual-system specification), with two sets of remote signal transmission devices. Each device is independently equipped with a dedicated 4-core single-mode armored optical cable. The two systems are physically isolated, so a failure in one system does not affect the operation of the other, significantly improving circuit reliability.

[0030] Substation side: Core primary equipment: 750kV main transformer, circuit breakers on each side of the main transformer, matching disconnect switches (DS3), and grounding switches (ES3, Q11, Q21); Core secondary equipment: dual-configuration transformer protection A / B cabinet, transformer non-electrical quantity protection, transformer air-cooled control box, transformer fire / fire alarm module, and two sets of remote signaling devices paired with the power plant side; Signal flow direction: Sending signals outward: The main transformer protection trip output, failure start signal, and local disconnector / grounding switch position signal are sent to a remote signaling device and transmitted to the power plant side via optical fiber; Internal reception: Receives circuit breaker position and disconnector / grounding switch position signals transmitted from the power plant side via optical fiber, which are used for the control logic of main transformer air cooling and fire protection, as well as the electrical interlocking of disconnectors and grounding switches on this side.

[0031] Power plant side: Core primary equipment: 750kV high-voltage circuit breaker (7541), matching disconnect switches (12G, 13G), grounding switches (12GD, 23GD, Q21, etc.); Core secondary equipment: 7541 circuit breaker protection device, circuit breaker control cabinet, 2 sets of remote signaling devices; Signal flow direction: Sending signals outward: Send signals such as circuit breaker position, disconnector / grounding switch position, circuit breaker failure start signal, and trip circuit status to a remote signaling device, which then transmits them to the substation side via optical fiber; Internal reception: Receives the main transformer protection trip command and the grounding switch position interlocking signal transmitted from the substation side via optical fiber, drives the circuit breaker to trip, and realizes the electrical interlocking of the local disconnecting switch.

[0032] Main transformer protection trip output circuit: When the main transformer fails, the trip command of the main transformer protection on the substation side is transmitted to the power plant side through optical fiber, tripping the high-voltage circuit breaker such as 7541 on the power plant side, and simultaneously activating the circuit breaker failure protection and blocking reclosing.

[0033] Main transformer air-cooled control circuit: The opening position signal of the circuit breaker on the power plant side is transmitted back to the substation side through optical fiber, and then connected in series to the automatic switching control circuit of the main transformer cooler.

[0034] Fire control circuit of main transformer: The trip position signal of the circuit breaker on the power plant side is transmitted back to the substation side through optical fiber, and then connected in series to the start control circuit of the main transformer fire protection system.

[0035] Circuit breaker failure tripping circuit: When the 7541 circuit breaker on the power plant side fails, the failure start signal is transmitted to the substation side through optical fiber, triggering the main transformer protection to trip the circuit breakers on all sides of the main transformer, completely isolating the fault.

[0036] Two-way five-prevention electrical interlocking circuit: The position signals of the disconnecting switches and grounding switches on both sides are transmitted to each other through optical fiber, and the normally closed contact of the grounding switch on the opposite side is connected in series with the interlocking circuit of the disconnecting switch on this side to prevent malicious electrical misoperation such as energizing the grounding switch with the grounding switch on or closing the grounding switch with the grounding switch on, thus meeting the five-prevention safety requirements of the power system.

[0037] 1. Main transformer protection trip output In the event of a fault within the transformer zone, both the dual-configuration 750kV main transformer power protection devices A and B must trip the 7541 and 7540 circuit breakers on the power plant side, triggering a circuit breaker failure and simultaneously blocking reclosing. This circuit transmits information from the substation side to the power plant side via dedicated fiber optic communication. See the detailed circuit logic below. Figure 2 .

[0038] When a transformer fails, the single-unit 750kV main transformer non-electrical quantity protection device must trip the 7541 and 7540 circuit breakers on the power plant side and block reclosing. This circuit transmits information from the substation side to the power plant side via dedicated fiber optic communication. See the detailed circuit logic below. Figure 2 .

[0039] 2. Main transformer air-cooling control circuit The normally closed contacts of the circuit breakers on each side of the main transformer need to be connected in series and then connected to the automatic start-up control circuit of the main transformer cooler via a reactivation relay. The position nodes of the 7541 and 7540 circuit breakers on the high-voltage side of the main transformer transmit information via a dedicated fiber optic communication device from the power plant side to the substation side. See the detailed circuit logic below. Figure 2 .

[0040] 3. Fire control circuit of main transformer The normally closed contacts of the circuit breakers on each side of the main transformer need to be connected in series and then connected to the main transformer fire-fighting start control circuit via a reactivation relay. The position nodes of the 7541 and 7540 circuit breakers on the high-voltage side of the main transformer transmit information via a dedicated fiber optic communication device from the power plant side to the substation side. See the detailed circuit logic below. Figure 2 .

[0041] 4. 750kV circuit breaker failure tripping circuit When the protection devices of circuit breakers 7541 and 7540 on the high-voltage side of the main transformer fail, the 750kV main transformer protection devices A and B must trip, opening the circuit breakers on each side of the main transformer. This circuit transmits information via dedicated fiber optic communication from the power plant side to the substation side via a remote signal transmission device. See the detailed circuit logic below. Figure 2 .

[0042] 5. Electrical interlocking circuit between substation and power plant 5.1 Power plant side 12G and 13G blocking logic According to the five-prevention requirements of the power system, the 12G and 13G interlocking logic circuits need to consider the interlocking relationship between the substation-side disconnectors ES3 and Q21. The circuit design requires that the normally closed contacts of disconnectors ES3 and Q21 be connected in series with the 12G and 13G interlocking circuits to prevent the risk of energizing with the grounding switch connected. This circuit transmits information from the substation-side remote signal transmission device to the power plant-side remote signal transmission device via dedicated fiber optic communication. See the specific circuit logic below. Figure 2 .

[0043] 5.2, Substation-side DS3 and Q11 blocking logic According to the five-prevention requirements of the power system, the DS3 and Q11 interlocking logic circuits need to consider the interlocking relationship of the power plant-side disconnector 23GD. The circuit design requires that the normally closed contact of disconnector 23GD be connected in series with the DS3 and Q11 interlocking circuits to prevent the risk of energizing with the grounding switch connected. This circuit transmits information from the power plant-side remote signal transmission device to the substation-side remote signal transmission device via dedicated fiber optic communication. See the specific circuit logic below. Figure 2 .

[0044] 5.3 Substation Side Q21 Blocking Logic According to the five-prevention requirements of the power system, the Q21 interlocking logic circuit needs to consider the interlocking relationship of disconnectors 12G and 13G on the power plant side. The circuit design requires that the normally closed contacts of disconnectors 12G and 13G be connected in series with the Q21 interlocking circuit to prevent risks associated with energized and grounding switches. This circuit transmits information from the power plant side's remote signal transmission device to the substation side's remote signal transmission device via dedicated fiber optic communication. See the specific circuit logic below. Figure 2 Schematic diagram of the circuit logic of the remote signaling device between the substation and the power plant.

[0045] Based on the complete control loop logic, this invention employs a remote signal transmission device and completes information interaction through dedicated optical fiber communication. It realizes the design schemes for the main transformer protection trip output of 750kV substation, the main transformer air-cooling control loop, the main transformer fire control loop, the 750kV circuit breaker failure tripping on the power plant side, and the interlocking loop between the substation and the power plant, thereby improving the reliability of the control loop and ensuring the safe and reliable operation of the power system.

[0046] This invention addresses the use of a remote signal transmission device for long-distance control circuits in substations. It utilizes dedicated optical fiber communication to transmit signals such as tripping, malfunction tripping, and circuit breaker / disconnector positions to achieve information exchange. This avoids the risk of control circuit malfunctions caused by interference signals due to distributed capacitance of long cables, resulting in high safety and reliability for electrical control circuits.

[0047] Example 2 A long-distance control method for substations includes the following steps: Perform remote control operations from the substation side to the power plant side: The control signals output from the signal output terminal of the substation-side control unit are respectively connected to the signal input terminals of the first substation-side signal device and the second substation-side signal device; the two control signals are respectively transmitted to the first power plant-side signal device and the second power plant-side signal device via the first dedicated optical fiber communication link and the second dedicated optical fiber communication link; the two control signals output from the signal output terminals of the first power plant-side signal device and the second power plant-side signal device are respectively connected to the control and interlocking circuit input terminals of the power plant-side control unit, and the power plant-side switchgear is controlled and interlocked through the dual redundant signal; Perform remote control operations from the power plant side to the substation side: The control signals output from the power plant-side control unit are connected to the signal input terminals of the first power plant-side signaling device and the second power plant-side signaling device, respectively. The two control signals are transmitted to the first substation-side signaling device and the second substation-side signaling device via the first dedicated optical fiber communication link and the second dedicated optical fiber communication link, respectively. The two control signals output from the signal output terminals of the first substation-side signaling device and the second substation-side signaling device are connected to the control and interlocking circuit input terminals of the substation-side control unit, respectively. The substation-side main transformer protection is controlled and interlocked through the dual redundant signal.

[0048] Many embodiments and applications beyond the examples provided will be apparent to those skilled in the art upon reading the foregoing description. Therefore, the scope of this teaching should not be determined by reference to the foregoing description, but rather by reference to the foregoing and the full scope of its equivalents. For purposes of completeness, all articles and references, including disclosures in patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein is not intended as a waiver of that subject matter, nor should it be construed as an indication that the applicant has not considered that subject matter as part of the disclosed inventive subject matter.

[0049] The above content provides a further detailed description of the present invention. It should not be construed that the specific embodiments of the present invention are limited to this. For those skilled in the art, several simple deductions or substitutions can be made without departing from the concept of the present invention, and all such deductions or substitutions should be considered to fall within the scope of protection defined by the present invention.

Claims

1. A long-distance control loop for a substation, characterized in that, It includes a substation-side control unit, a power plant-side control unit, a first remote signal transmission unit, and a second remote signal transmission unit; the first remote signal transmission unit and the second remote signal transmission unit are mutually independent with dual redundancy configuration; The substation-side control unit is equipped with a control and interlocking circuit for the main transformer, and the power plant-side control unit is equipped with a control and interlocking circuit for switchgear. The first remote signal transmission unit includes a first substation-side signal device and a first power plant-side signal device, and the first substation-side signal device and the first power plant-side signal device are bidirectionally connected via a first dedicated optical fiber communication link. The second remote signal transmission unit includes a second substation-side signal device and a second power plant-side signal device. The second substation-side signal device and the second power plant-side signal device are bidirectionally connected via a second dedicated optical fiber communication link. The signal output terminal of the substation-side control unit is connected to the signal input terminals of the first substation-side signal device and the second substation-side signal device, respectively. The signal output terminals of the first substation-side signal device and the second substation-side signal device are connected to the control and interlocking circuit input terminals of the power plant-side control unit, respectively. The signal output terminal of the power plant-side control unit is connected to the signal input terminals of the first power plant-side signal device and the second power plant-side signal device, respectively. The signal output terminals of the first power plant-side signal device and the second power plant-side signal device are connected to the control and interlocking circuit input terminals of the substation-side control unit, respectively.

2. The long-distance control loop for a substation according to claim 1, characterized in that, The first dedicated optical fiber communication link and the second dedicated optical fiber communication link are independent dedicated single-mode armored optical cable communication links.

3. The long-distance control loop for a substation according to claim 1, characterized in that, The power supply, signal input circuit, signal output circuit, and communication link of the first remote signal transmission unit and the second remote signal transmission unit are all physically isolated from each other.

4. A long-distance control loop for a substation according to claim 1, characterized in that, The substation-side control unit includes a main transformer protection device, a main transformer-side actuator, a substation-side switchgear, and a substation-side electrical interlocking circuit. The signal output terminal of the substation-side control unit includes the action output contact of the main transformer protection device and the position feedback contact of the substation-side switchgear. The input terminals of the control and interlocking circuits of the substation-side control unit include the control circuit input terminal of the main transformer-side actuator and the input terminal of the substation-side electrical interlocking circuit.

5. A long-distance control loop for a substation according to claim 4, characterized in that, The main transformer protection device includes a first main transformer power protection device, a second main transformer power protection device, and a main transformer non-power protection device; the first main transformer power protection device and the second main transformer power protection device are mutually independent and redundantly configured; the main transformer non-power protection device is a single set configuration. The operation output contacts of the first main transformer power protection device are only connected to the signal input terminal of the first substation-side signal device, and the operation output contacts of the second main transformer power protection device are only connected to the signal input terminal of the second substation-side signal device. The operation output contacts of the main transformer non-electrical quantity protection device are respectively connected to the signal input terminals of the first substation-side signal device and the second substation-side signal device.

6. A long-distance control loop for a substation according to claim 4, characterized in that, The main transformer side actuators include circuit breakers on each side of the main transformer, air-cooled control devices for the main transformer, and fire-fighting control devices for the main transformer. The tripping circuit input terminals of the circuit breakers on each side of the main transformer, the control circuit input terminals of the air-cooled control device of the main transformer, and the control circuit input terminals of the fire-fighting control device of the main transformer are respectively connected to the signal output terminals of the first power plant side signal device and the second power plant side signal device. The control circuits of the main transformer air-cooling control device and the main transformer fire-fighting control device are all connected in series with the normally closed position contacts of the power plant side high-voltage circuit breaker transmitted through the first power plant side signal device and the second power plant side signal device.

7. A long-distance control loop for a substation according to claim 4, characterized in that, The power plant-side control unit includes a high-voltage circuit breaker, power plant-side switchgear, circuit breaker protection device, circuit breaker control cabinet, and power plant-side electrical interlocking circuit. The signal output terminal of the power plant-side control unit includes the action output contact of the circuit breaker protection device, the position feedback contact of the high-voltage circuit breaker, and the position feedback contact of the power plant-side switchgear. The control and interlocking circuit input terminals of the power plant side control unit include the trip control circuit input terminal of the circuit breaker control cabinet and the input terminal of the power plant side electrical interlocking circuit; The failure action output contacts of the circuit breaker protection device are respectively connected to the signal input terminals of the first power plant side signal device and the second power plant side signal device; The signal output terminals of the first substation-side signal device and the second substation-side signal device are respectively connected to the input terminal of the failure tripping circuit of the main transformer protection device.

8. A long-distance control loop for a substation according to claim 7, characterized in that, The position feedback contact of the substation-side switchgear is transmitted through the first substation-side signal device, the first dedicated optical fiber communication link, and the first power plant-side signal device, and then connected to the input terminal of the power plant-side electrical interlocking circuit. The position feedback contact of the power plant-side switchgear is transmitted through the first power plant-side signal device, the first dedicated optical fiber communication link, and the first substation-side signal device, and then connected to the input terminal of the substation-side electrical interlocking circuit. The second remote signal transmission unit is synchronously configured with the first remote signal transmission unit to form a bidirectional position signal transmission and interlocking circuit, thus forming a dualized cross-station electrical interlocking circuit.

9. A long-distance control loop for a substation according to claim 8, characterized in that, The substation-side switchgear includes a substation-side disconnector and a substation-side grounding switch; the power plant-side switchgear includes a power plant-side disconnector and a power plant-side grounding switch. The normally closed contact of the substation-side grounding switch is connected to the electrical interlocking circuit of the power plant-side disconnector, the normally closed contact of the power plant-side grounding switch is connected to the electrical interlocking circuit of the substation-side disconnector, and the normally closed contact of the power plant-side disconnector is connected to the electrical interlocking circuit of the substation-side grounding switch, forming a cross-station five-prevention interlocking circuit.

10. A long-distance control method for a substation according to claim 9, characterized in that, Includes the following steps: Perform remote control operations from the substation side to the power plant side: The control signals output from the signal output terminal of the substation-side control unit are respectively connected to the signal input terminals of the first substation-side signal device and the second substation-side signal device; the two control signals are respectively transmitted to the first power plant-side signal device and the second power plant-side signal device via the first dedicated optical fiber communication link and the second dedicated optical fiber communication link; the two control signals output from the signal output terminals of the first power plant-side signal device and the second power plant-side signal device are respectively connected to the control and interlocking circuit input terminals of the power plant-side control unit, and the power plant-side switchgear is controlled and interlocked through dual redundant signals; Perform remote control operations from the power plant side to the substation side: The control signals output from the power plant-side control unit are connected to the signal input terminals of the first power plant-side signaling device and the second power plant-side signaling device, respectively. The two control signals are transmitted to the first substation-side signaling device and the second substation-side signaling device via the first dedicated optical fiber communication link and the second dedicated optical fiber communication link, respectively. The two control signals output from the signal output terminals of the first substation-side signaling device and the second substation-side signaling device are connected to the control and interlocking circuit input terminals of the substation-side control unit, respectively, to control and interlock the protection of the substation-side main transformer through dual redundant signals.

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