Relay control circuit for steam turbine trip and overspeed protection

Abstract

The utility model belongs to the field of steam turbine control and protection systems, and particularly relates to a relay control circuit for steam turbine trip and overspeed protection, which comprises a trip protection master control loop, a high-voltage interruption solenoid valve control loop, a mechanical shutdown electromagnet control loop, a main throttle valve solenoid valve drive loop, an OPC overspeed protection loop, a control valve solenoid valve drive loop and the like. Two ends of all TR coils of the trip protection main control loop are respectively connected with the on-off protection control circuit I and a direct current power supply cathode line, and contacts of TR are distributed and connected in each loop; the on-off protection control circuit I comprises a DEH shutdown protection unit, a 110% overspeed protection unit, an ETS shutdown protection unit and an expansion item shutdown protection unit which are connected in parallel, and the DEH shutdown protection unit and the ETS shutdown protection unit are both of an H-shaped structure. According to the technical scheme, the defects in the prior art are fundamentally overcome by optimizing a contact distribution mode, adopting an H-type redundancy architecture, enhancing hardware protection measures and the like.

Description

Technical Field

[0001] This utility model belongs to the field of steam turbine control and protection systems, and particularly relates to a relay control circuit for steam turbine trip and overspeed protection. Background Technology

[0002] In a steam turbine control and protection system, when an emergency occurs requiring immediate shutdown, all steam inlet valves must be closed quickly, as the reliability of the emergency shutdown function of the steam turbine control and protection system is directly related to equipment safety and personnel safety.

[0003] In response to this, existing technologies, such as the Chinese utility model patent document with application number 2022231709743, disclose a "Control Device for Overspeed Protection and Emergency Shutdown," which includes an overspeed protection relay logic integrated circuit board, an emergency shutdown relay logic integrated circuit board, an emergency shutdown solenoid valve, an overspeed protection solenoid valve, a valve, and a servo valve. Both the overspeed protection relay logic integrated circuit board and the emergency shutdown relay logic integrated circuit board are respectively provided with a power supply interface, a signal input interface, and a signal output interface. The overspeed protection relay logic integrated circuit board also has several overspeed protection relays and overspeed protection solenoid valve interfaces; the emergency shutdown relay logic integrated circuit board also has several emergency shutdown relays and emergency shutdown solenoid valve interfaces. This control device can effectively solve the problems of not being able to cover multiple types and having many wiring connections. However, it still has the following drawbacks:

[0004] 1) Design flaw in the manual shutdown button: The normally open contact of the manual shutdown button needs to be connected in series with the main circuit of the shutdown protection relay, and then the high-voltage tripping solenoid valve (AST solenoid valve) is controlled through the relay's extended contacts. This design does not directly connect the button to the shutdown drive circuit, which does not comply with the requirement in Chapter 15.6.1 of the "GB50660-2011 Design Code for Large and Medium-sized Thermal Power Plants" that "the trip button should be directly connected to the shutdown drive circuit." This poses a risk that the shutdown will fail due to relay or contact failure after the button is activated in an emergency.

[0005] 2) Single-point protection issue for ETS shutdown signals: The "ETS trip 1" and "ETS trip 2" signals sent by the ETS are each connected in parallel with other shutdown signals through only one normally open contact, forming a single-point protection logic. When any signal is falsely triggered (such as electromagnetic interference or component failure), it can easily lead to the unit tripping falsely, affecting system stability.

[0006] 3) Risk of DEH trip signal failure: The two "DEH trip" signals sent by the DEH system adopt a two-out-of-two logic, which is first connected in series and then in parallel. If one of the signals fails due to a DO channel fault or line interruption, the other signal cannot trigger the trip independently, which may result in protection failure. Especially in emergency situations, this may delay shutdown and cause equipment damage.

[0007] 4) Potential for OPC overspeed protection malfunction: The "software OPC action" signal sent by the DEH is a single-point output, which drives the OPC relay after being connected in parallel with other overspeed signals. Single-point signals have poor anti-interference capabilities. When the system software malfunctions or the hardware malfunctions, it can easily lead to the OPC circuit being falsely triggered, causing the regulating valve to close frequently and affecting the normal operation of the unit.

[0008] 5) Load > 15% signal logic defect: The "Load > 15%" signal has only a single DO output, which is connected in series with the normally closed contact of a single generator and then connected to the OPC circuit. This design does not consider signal redundancy. When any link in the signal transmission link fails, it may cause the OPC protection to fail during load shedding, and the regulating valve cannot be closed in time to suppress the speed surge.

[0009] Furthermore, the Chinese utility model patent document with application number 2018213376327, entitled "A Novel Turbine Shutdown Button Trigger Structure," includes contact 1, contact 2, contact 3, and contact 4 of shutdown button 1; contact 1, contact 2, contact 3, and contact 4 of shutdown button 2; controller output relay 1, controller output relay 2, controller output relay 3, and controller output relay 4; controller output channel DO1, controller output channel DO2, controller output channel DO3, and controller output channel DO4; and shutdown solenoid valves AST1, AST2, AST3, and AST4. The advantage of this solution is that it achieves rapid and accurate fault alarm and improves the reliability of the turbine shutdown signal. However, in this scheme, the contacts of the two manual stop buttons control two sets of AST solenoid valves (such as AST1 / AST3, AST2 / AST4) respectively by connecting four sets of normally closed contacts in parallel and then in series. Although this design adopts a series-parallel structure, each pair of contacts directly controls one set of solenoid valves. If a set of contacts or the circuit fails, the corresponding set of solenoid valves will not operate normally, thus failing to achieve independent control of all AST solenoid valves.

[0010] In summary, the core flaw of existing technologies lies in:

[0011] Insufficient reliability of signal logic architecture: Most existing solutions adopt single-point protection or simple two-out-of-two logic, which do not form a dual redundancy architecture to resist false operation and failure to operate, and cannot meet the protection requirements of high security scenarios.

[0012] The manual stop circuit does not meet the specifications: the manual stop button is not directly connected to the solenoid valve drive circuit, but relies on intermediate relay switching, which increases the circuit failure point and reduces the real-time performance and reliability of emergency stop.

[0013] Lack of hardware protection measures: such as the electromagnet being prone to burnout due to prolonged energization during mechanical shutdown, and the lack of effective suppression of arcing phenomena. Existing technologies lack targeted designs, resulting in shortened hardware lifespan and increased maintenance costs.

[0014] Insufficient compliance with standards and specifications: Some designs do not meet the requirements of industry standards such as GB50660, posing compliance risks in engineering applications and making it difficult to pass safety certification. Utility Model Content

[0015] The purpose of this invention is to address the shortcomings of the existing technology by optimizing the contact allocation method, adopting an H-type redundant architecture, and enhancing hardware protection measures. The aim is to provide a compliant and highly reliable turbine trip and overspeed protection relay circuit, fundamentally solving the defects of the existing technology.

[0016] To achieve the above objectives, the present invention adopts the following technical solution:

[0017] A relay control circuit for turbine trip and overspeed protection includes a trip protection main control circuit, a high-pressure shutdown solenoid valve control circuit, a mechanical shutdown electromagnet control circuit, a main steam valve solenoid valve drive circuit, an OPC overspeed protection circuit, and a regulating valve solenoid valve drive circuit.

[0018] The trip protection main control circuit includes a switching protection control circuit I and several trip relays TR; the input terminals of all trip relay TR coils are connected to the positive line of the DC power supply through the switching protection control circuit I, and the output terminals are connected to the negative line of the DC power supply; the contacts of each trip relay TR are distributed and connected to the high-voltage trip solenoid valve control circuit, the mechanical shutdown solenoid control circuit, the main steam valve solenoid valve drive circuit, and the OPC overspeed protection circuit.

[0019] The on / off protection control circuit I includes a DEH stop protection unit, a 110% overspeed protection unit, an ETS stop protection unit, and an extended item stop protection unit connected in parallel. The DEH stop protection unit includes four normally open contacts DEH-DO digital output channels connected in an "H"-shaped structure. k The ETS shutdown protection unit includes four normally open contacts (ETS-DO) digital output channels connected in an "H" configuration. k .

[0020] The OPC overspeed protection circuit includes a switching protection control circuit II and several overspeed protection control relays OR; the input terminals of all overspeed protection control relays OR coils are connected to the positive line of the DC power supply through the switching protection control circuit II, and the output terminals are connected to the negative line of the DC power supply; the contacts of each overspeed protection control relay OR are distributed and connected in the control valve solenoid valve drive circuit.

[0021] Preferably, the trip relays TR in the trip protection main control circuit include relays TR1, TR2, TR3, TR4, TR5, TR6, TR7, TR8, TR9 and TR10.

[0022] Preferably, the input terminal of the mechanical stop electromagnet control circuit is connected to the positive line of a DC power supply, and the output terminal is connected to the negative line of a DC power supply; the normally open contact TR1 of the relay TR1... 1-1 The mechanical stop electromagnet control circuit is connected, and the coil input terminal of relay TR1 is connected to a normally closed digital output channel contact DEH-DO. b .

[0023] Preferably, the high-voltage tripping solenoid valve control circuit includes four high-voltage tripping control branches: AST-HPT1, AST-HPT2, AST-HPT3, and AST-HPT4. The input terminals of all high-voltage tripping control branches are connected to the positive power line of the high-voltage tripping solenoid valve, and the output terminals are connected to the negative power line. Each high-voltage tripping control branch is connected to a normally closed digital output channel contact DEH-DO. b Normally closed contact of digital output channel ETS-DO b And the manual stop control module. Normally closed contacts TR2, TR3, TR4, and TR5. 2-1 TR 3-1 TR 4-1 and TR 5-1 Each of the four high-shading control branches is connected in a one-to-one correspondence.

[0024] Preferably, the high-voltage shutdown solenoid valve control circuit includes a manual stop button I and a manual stop button II on the control panel. The control branch of the high-voltage shutdown solenoid valve AST-HPT1 is connected in parallel with the control branch of the high-voltage shutdown solenoid valve AST-HPT3. The normally closed contact 1-1 of the manual stop button I and the normally closed contact 2-1 of the manual stop button II are connected in parallel to form the manual stop control module in the control branch of the high-voltage shutdown solenoid valve AST-HPT1. The normally closed contact 1-3 of the manual stop button I and the normally closed contact 2-3 of the manual stop button II are connected in parallel to form the manual stop control module in the control branch of the high-voltage shutdown solenoid valve AST-HPT3. The control branch of the high-voltage shut-off solenoid valve AST-HPT2 is connected in parallel with the control branch of the high-voltage shut-off solenoid valve AST-HPT4. The normally closed contacts 1-2 of the manual stop button I and 2-2 of the manual stop button II on the control panel are connected in parallel to form the manual stop control module in the control branch of the high-voltage shut-off solenoid valve AST-HPT2. The normally closed contacts 1-4 of the manual stop button I and 2-4 of the manual stop button II on the control panel are connected in parallel to form the manual stop control module in the control branch of the high-voltage shut-off solenoid valve AST-HPT4.

[0025] Preferably, the main steam valve solenoid valve drive circuit includes twelve parallel main steam valve solenoid valve drive branches, namely, the drive branch for fast-closing solenoid valve FSV-MSV1, the drive branch for fast-closing solenoid valve FSV-MSV2, the drive branch for fast-closing solenoid valve FSV-RSV1, the drive branch for fast-closing solenoid valve FSV-RSV2, the drive branch for test solenoid valve TSV-MSV1, the drive branch for test solenoid valve TSV-MSV2, the drive branch for test solenoid valve TSV-RSV1, the drive branch for test solenoid valve TSV-RSV2, the drive branch for fast-closing solenoid valve FSV-SPMSV1, the drive branch for fast-closing solenoid valve FSV-SPMSV2, the drive branch for test solenoid valve TSV-SPMSV1, and the drive branch for test solenoid valve TSV-SPMSV2.

[0026] Preferably, each of the main steam valve solenoid valve drive branches is connected to a normally open digital output channel contact DEH-DO. k The normally open contact TR of relay TR6 6-1 The normally open contact DEH-DO of the digital output channel connected in parallel to the drive branch of the fast-closing solenoid valve FSV-MSV1 k Both ends. The normally open contact TR of relay TR7. 7-1 The normally open contact DEH-DO of the digital output channel connected in parallel to the drive branch of the fast-closing solenoid valve FSV-MSV2 k Both ends. The normally open contact TR of relay TR8. 8-1The normally open contact DEH-DO of the digital output channel connected in parallel to the drive branch of the fast-closing solenoid valve FSV-RSV1 k Both ends. The normally open contact TR of relay TR9. 9-1 The normally open contact DEH-DO of the digital output channel connected in parallel to the drive branch of the fast-closing solenoid valve FSV-RSV2 k Both ends. The normally open contact TR of relay TR8. 8-2 The normally open contact DEH-DO of the digital output channel connected in parallel to the drive branch of the fast-closing solenoid valve FSV-SPMSV1 k Both ends. The normally open contact TR of relay TR9. 9-2 The normally open contact DEH-DO of the digital output channel connected in parallel to the drive branch of the fast-closing solenoid valve FSV-SPMSV2 k Both ends.

[0027] Preferably, the on / off protection control circuit II of the OPC overspeed protection circuit includes a shutdown protection unit, a load shedding protection unit, an OPC action protection unit, and a 103% overspeed protection unit connected in parallel; the normally open contacts TR6 and TR10 of relays TR6 and TR10 are... 6-2 and TR 10-2 They are connected in series in the shutdown protection unit.

[0028] Preferably, the OPC action protection unit includes four normally open contacts DEH-DO digital output channels connected in an "H"-shaped structure. k .

[0029] Preferably, the load shedding protection unit includes four control switches connected in an "H"-shaped configuration; the four control switches are normally open contacts DEH-DO of two parallel digital output channels. k And two parallel generators connected to the grid via normally closed contacts OUT-NC.

[0030] Preferably, the OPC overspeed protection circuit includes several overspeed protection control relays OR1, OR2, OR3, OR4, OR5, OR6, OR7, OR8, OR9, OR10, OR11 and OR12.

[0031] Preferably, the regulating solenoid valve drive circuit includes eleven parallel regulating solenoid valve drive branches, namely, the fast-closing solenoid valve FSV-CV1 drive branch, the fast-closing solenoid valve FSV-CV2 drive branch, the fast-closing solenoid valve FSV-PCV1 drive branch, the fast-closing solenoid valve FSV-PCV2 drive branch, the fast-closing solenoid valve FSV-ICV1 drive branch, the fast-closing solenoid valve FSV-ICV2 drive branch, the overspeed limiting solenoid valve OPC-HPT1 drive branch, the overspeed limiting solenoid valve OPC-HPT2 drive branch, the rotating partition fast-closing solenoid valve FSV-RB1 drive branch, the fast-closing solenoid valve FSV-SPCV1 drive branch, and the fast-closing solenoid valve FSV-SPCV2 drive branch.

[0032] Preferably, each of the aforementioned control valve solenoid valve drive circuits is connected to a normally open digital output channel contact DEH-DO. k The normally open contacts of relays OR1, OR2, OR3, OR4, OR5, OR6, OR7, OR8, OR9, OR11, and OR12 1-1 OR 2-1 OR 3-1 OR 4-1 OR 5-1 OR 6-1 OR 7-1 OR 8-1 OR 9-1 OR 11-1 and OR 12-1 The normally open contacts of the digital output channels DEH-DO are connected one-to-one with the eleven solenoid valve drive branches. k Both ends.

[0033] The beneficial effects of this utility model are:

[0034] 1. The manual stop circuit directly drives the solenoid valve, conforming to industry standards.

[0035] The normally closed contacts of the two manual stop buttons on the control panel are directly connected in parallel and then in series in the high-voltage shutdown control branch. When the manual stop button on the control panel is pressed in an emergency, the power supply to the high-voltage shutdown solenoid valve is directly cut off, the safety oil is removed, and all steam inlet valves are closed. The four normally closed contacts of each manual stop button on the control panel distribute and control the four high-voltage shutdown control branches, forming a "dual-button redundancy + direct drive" architecture, which meets the specifications and avoids shutdown failure caused by the failure of the intermediate relay used in the existing technology.

[0036] II. The ETS and DEH stop signals adopt an H-type redundancy architecture to avoid false alarms and failures to operate.

[0037] Compared to existing technologies where ETS and DEH stop signals use single-point or simple two-out-of-two logic, which are prone to false tripping or protection failure due to single-point faults, the ETS and DEH stop protection units in this technical solution both adopt an "H-type" architecture with "four-out-of-two" logic. This dual redundancy architecture improves the anti-interference capability of the stop signal and significantly reduces the false tripping rate and the failure to operate rate.

[0038] III. The OPC overspeed protection circuit features multiple redundancies to suppress malfunctions and enhance reliability.

[0039] Compared to the single-point output of OPC action signals, which is prone to frequent valve closure due to software anomalies or hardware malfunctions, and the lack of redundancy in load shedding protection signals, which may lead to failure, this technical solution addresses these issues. The OPC action protection unit employs four H-shaped DO channels, with a "two-out-of-four" logic ensuring that OPC is not triggered by a single card malfunction, and only operates when at least two upper and lower cards are outputting normally, thus preventing false triggering. The load shedding protection unit forms an H-shaped structure with two "load > 15%" DO signals and two normally closed contacts for generator grid connection (i.e., generator disconnection), triggering OPC only when "load > 15%" and "generator disconnection" occurs, preventing protection failure due to a single signal fault. The 103% overspeed protection unit is connected in parallel with the software OPC, forming a "hardware + software" dual protection system, ensuring that overspeed protection is still triggered even with a fault in the DEH system's DO output card when the unit exceeds 103% overspeed.

[0040] IV. Time-limited energization and arc extinguishing design of the electromagnet for mechanical shutdown, extending hardware lifespan.

[0041] Compared to existing technologies where mechanical stop electromagnets are prone to burnout due to prolonged energization, arcing is not suppressed, and hardware lifespan is short, this technical solution uses a separate relay TR1 to control the mechanical stop electromagnet. The input terminal of relay TR1 is connected to a normally closed contact of a digital output channel, ensuring it is only briefly energized during stop protection operation, thus avoiding long-term energization losses. Furthermore, a reverse diode is connected in parallel across the mechanical stop electromagnet to suppress the induced electromotive force during power-off, reducing arcing and extending hardware lifespan.

[0042] V. Multiple redundancies in the high-voltage trip solenoid valve control circuit ensure reliable shutdown.

[0043] Compared to existing solutions where the high-voltage shutdown solenoid valve control circuit is controlled by a single point or in groups, a contact or wiring fault could cause some solenoid valves to fail to operate. This technical solution designs four independent high-voltage shutdown solenoid valve control branches, each branch connected in series with a normally closed contact ETS-DO digital output channel. b Normally closed contact of trip relay TR, normally closed contact of digital output channel DEH-DO bThe system includes manual shutdown, which is achieved by connecting four high-voltage shut-off solenoid valve control branches in parallel to form a logic of "normally closed contacts in series + redundant power supply + manual intervention". The manual shutdown system uses parallel connection of two normally closed contacts on two buttons to ensure that if one button fails, the other button keeps the solenoid valve energized, thus enabling independent control of all high-voltage shut-off solenoid valves.

[0044] VI. The main steam valve and regulating valve solenoid valve drive circuits are dual-drive to prevent failure to operate due to DO channel malfunction.

[0045] Compared to existing technologies where solenoid valve actuation relies on a single DO channel, which can lead to valve failure due to jamming or circuit malfunctions, this technical solution addresses this issue. In the main steam valve solenoid valve actuation circuit, the fast-closing solenoid valve actuation branch utilizes a normally open contact of the trip relay TR connected in parallel with the normally closed contact of the DEH DO output channel. Even if the DO channel fails, the normally open contact of the trip relay TR can still close after the coil actuates, energizing the solenoid valve to close. Furthermore, the normally open contact of the trip relay TR closes faster, meeting the "fast closing" requirement. In the regulating valve solenoid valve actuation circuit, the normally open contact of the overspeed protection control relay OR is connected in parallel with the normally closed contact of the DEH DO output channel. When OPC is triggered, the overspeed protection control relay OR actuates rapidly, ensuring that even if the DO channel fails, the relay contacts can still conduct the circuit and close the regulating valve.

[0046] VII. Reserved expansion interfaces to enhance the scalability of protection functions.

[0047] Compared to existing solutions with fixed protection functions that cannot flexibly add new protection signals, this technical solution incorporates an "extension shutdown protection unit" in the trip protection main control circuit. It provides interfaces for connecting additional protection signals such as those from the DEH control cabinet and ETS control cabinet power failure, allowing for the expansion of protection dimensions and improved system adaptability based on actual needs. Attached Figure Description

[0048] Figure 1 A schematic diagram of the main control circuit for trip protection with a preferred structure;

[0049] Figure 2 Schematic diagram of a control circuit for a high-pressure shut-off solenoid valve with a preferred structure;

[0050] Figure 3 A schematic diagram of a preferred mechanical stop electromagnet control circuit.

[0051] Figure 4 Schematic diagram of a preferred structure for the main steam valve solenoid valve drive circuit;

[0052] Figure 5 A schematic diagram of a preferred OPC overspeed protection circuit.

[0053] Figure 6 This is a schematic diagram of a preferred three-out-of-two logic module structure;

[0054] Figure 7 This is a schematic diagram of a preferred structure for a control valve solenoid valve drive circuit. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments.

[0056] Therefore, the following detailed description of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0057] Example 1

[0058] This embodiment discloses a relay control circuit (hereinafter referred to as the relay control circuit) for turbine trip and overspeed protection. As a preferred embodiment of this utility model, it is the core execution unit of the turbine safety protection system. Its core function is to quickly trigger a shutdown command through multiple redundant logics when the turbine experiences emergency conditions (such as overspeed, equipment failure, or abnormal parameters), control the operation of relevant solenoid valves, and close all steam inlet valves (main steam valve and regulating steam valve) to prevent equipment damage or safety accidents. This architecture achieves layered control of turbine shutdown protection and overspeed protection through the independent design of the "trip protection main control circuit" and the "OPC overspeed protection circuit," ensuring the accuracy of protection response under different fault scenarios. Specifically, the relay control circuit includes a trip protection main control circuit, a high-pressure trip solenoid valve control circuit, a mechanical shutdown electromagnet control circuit, a main steam valve solenoid valve drive circuit, an OPC overspeed protection circuit, and a regulating valve solenoid valve drive circuit.

[0059] like Figure 1 As shown, the trip protection main control circuit includes on / off protection control circuit I and several trip relays TR.

[0060] The on / off protection control circuit I serves as the signal input hub for the main control circuit of the trip protection, and adopts a "parallel redundancy + H-type architecture" design. Specifically, the on / off protection control circuit I includes parallel DEH (Digital Electro-hydraulic Control System for Steam Turbines) shutdown protection units, 110% overspeed protection units, ETS (Emergency Trip Protection System) shutdown protection units, and extended shutdown protection units.

[0061] DEH Stop Protection Unit: Includes four normally open contacts of digital output channels connected in an "H"-shaped configuration. k ( Figure 1 DEH-DO in k1 DEH-DO k2 DEH-DO k3 and DEH-DO k4 These are the four DO signals (software shutdown signals) sent by the DEH system. The H-type architecture adopts a "two-out-of-four" logic (that is, the trigger circuit is turned on when any two DO channels output signals, one up and one down), which avoids false operation caused by a single card failure, and at the same time ensures that the shutdown can be reliably triggered when two or more cards are normal, thus solving the problem of single-point failure of DEH signals in the prior art.

[0062] ETS Shutdown Protection Unit: Includes four normally open contacts (ETS-DO) digital output channels connected in an "H" configuration. k ( Figure 1 ETS-DO k1 ETS-DO k2 ETS-DO k3 and ETS-DO k4 It receives four DO signals (hard-wired shutdown signals, such as pressure switch and displacement sensor trigger signals) from the ETS system. It also adopts the "two out of four" logic to improve the anti-interference capability of the ETS signal and avoid unit tripping caused by single-point false triggering.

[0063] 110% Overspeed Protection Unit: The three speed measurement modules configured in the DEH system, in addition to being used in the software control loop, can directly output a 110% overspeed contact signal from the speed measurement module when the turbine speed exceeds 110% of the rated value. After processing by taking two out of three, the signal is used for shutdown, serving as hardware redundancy for software protection. This ensures that when the unit overspeeds, shutdown can still be triggered through the hardware loop in the event of a fault in the DEH system DO output card or the ETS system.

[0064] Extended shutdown protection unit: Reserves interfaces to connect to other protection signals (such as power failure of DEH control cabinet, power failure of ETS control cabinet, etc.), realizes the scalability of protection functions, and ensures that the system can add protection dimensions according to actual needs.

[0065] The input terminals of all trip relays (TR) coils are connected to the positive DC power supply line via the on / off protection control circuit I, and the output terminals are connected to the negative DC power supply line. The contacts of each trip relay (TR) are distributed and connected to the high-voltage trip solenoid valve control circuit, the mechanical shutdown solenoid control circuit, the main steam valve solenoid valve drive circuit, and the OPC overspeed protection circuit. When any unit in the on / off protection control circuit I outputs a signal, the coil of the trip relay (TR) is energized, the corresponding contact actuates, and it participates in the control of the corresponding solenoid valve in each circuit.

[0066] like Figure 5 As shown, the OPC overspeed protection circuit includes a switching protection control circuit II and several overspeed protection control relays OR. The input terminals of all overspeed protection control relay OR coils are connected to the positive line of the DC power supply through the switching protection control circuit II, and the output terminals are connected to the negative line of the DC power supply. The contacts of each overspeed protection control relay OR are distributed and connected in the control valve solenoid valve drive circuit.

[0067] Example 2

[0068] This embodiment discloses a relay control circuit for turbine trip and overspeed protection. As a preferred embodiment of this invention, based on Embodiment 1, the trip protection main control circuit includes a relay TR1 among several trip relays TR. For example... Figure 3 As shown, the input terminal of the mechanical stop electromagnet control circuit is connected to the positive line of the DC power supply, and the output terminal is connected to the negative line of the DC power supply. In the mechanical stop electromagnet control circuit, fuse FU and the normally open contact TR of relay TR1 are connected in series from the input terminal to the output terminal. 1-1 The components include a mechanical stop electromagnet (MTS-METM) and a fuse (FU). The fuse (FU) protects the mechanical stop electromagnet control circuit from overcurrent damage.

[0069] Because the mechanical stop electromagnet MTS-METM has a high load power, it is prone to arcing and is easily burned out if energized for a long time. Therefore, a separate relay TR1 with arc extinguishing function is configured for the mechanical stop electromagnet. Its normally open contact TR 1-1 The mechanical shutdown electromagnet MTS-METM is energized to control the on / off state of the turbine. When the shutdown protection trips, the electromagnet MTS-METM is energized to remove the safety oil, triggering the turbine to shut down. A reverse diode is connected in parallel across the two ends of the MTS-METM electromagnet to suppress the induced electromotive force during de-energization, thus reducing arcing. Furthermore, a normally closed contact DEH-DO, a digital output channel, is connected to the coil input terminal of relay TR1. b ( Figure 1 DEH-DO in b1 Based on the normally closed contact DEH-DO of the digital output channel n1 The "Turbine shut down (delayed reset)" output signal is used to terminate the energized operation.

[0070] In summary, this technical solution utilizes relay TR1 and the normally closed contact DEH-DO of the digital output channel. b1The synergistic effect of this technology solves the problems of long-term energization damage and severe arcing of the MTS-METM mechanical shutdown electromagnet in existing technologies. The core of this structure lies in building a hardware logic of "time-limited energization + arc extinguishing protection" to ensure reliable operation of the solenoid valve during emergency shutdown, while avoiding unnecessary long-term energization losses and extending the life of the hardware.

[0071] Example 3

[0072] This embodiment discloses a relay control circuit for turbine trip and overspeed protection. As a preferred embodiment of this invention, based on embodiment 1 or 2, the trip protection main control circuit includes several trip relays TR2, TR3, TR4, and TR5. Based on this, the high-voltage trip solenoid valve control circuit is as follows: Figure 2 As shown, it includes four high-voltage shutdown control branches: AST-HPT1, AST-HPT2, AST-HPT3, and AST-HPT4. The input terminals of all high-voltage shutdown control branches are connected to the positive power supply line of the high-voltage shutdown solenoid valves, and the output terminals are connected to the negative power supply line of the high-voltage shutdown solenoid valves.

[0073] Each high-pressure shutdown control branch achieves reliable control of the high-pressure shutdown solenoid valve through a logic of "normally closed contacts in series + redundant power supply + manual intervention". The core function of this structure is to quickly cut off the safety oil supply and close all steam inlet valves during emergency shutdowns, while simultaneously using multiple redundancy designs to prevent protection failures caused by a single component malfunction. Specifically:

[0074] In the control branch of the high-voltage shut-off solenoid valve AST-HPT1, the fuse FU, the manual stop control module, and the normally closed contact ETS-DO of the digital output channel are connected in series from the input end to the output end. b1 The normally closed contact TR of relay TR2 2-1 Normally closed contact DEH-DO of digital output channel b2 High-pressure shut-off solenoid valve AST-HPT1 and fuse FU.

[0075] In the control branch of the high-voltage shut-off solenoid valve AST-HPT2, the fuse FU, the manual stop control module, and the normally closed contact ETS-DO of the digital output channel are connected in series from the input end to the output end. b2 The normally closed contact TR of relay TR3 3-1 Normally closed contact DEH-DO of digital output channel b3 High-pressure shut-off solenoid valve AST-HPT2 and fuse FU.

[0076] In the control branch of the high-voltage shut-off solenoid valve AST-HPT3, the fuse FU, the manual stop control module, and the normally closed contact ETS-DO of the digital output channel are connected in series from the input end to the output end. b3 The normally closed contact TR4 of relay TR4 4-1 Normally closed contact DEH-DO of digital output channel b4 High-pressure shut-off solenoid valve AST-HPT3 and fuse FU.

[0077] In the control branch of the high-voltage shut-off solenoid valve AST-HPT4, the fuse FU, the manual stop control module, and the normally closed contact ETS-DO of the digital output channel are connected in series from the input end to the output end. b4 The normally closed contact TR5 of relay TR5 5-1 Normally closed contact DEH-DO of digital output channel b5 High-pressure shut-off solenoid valve AST-HPT4 and fuse FU.

[0078] Based on the above structure, after each trip relay TR in the trip protection main control circuit operates, the normally closed contacts of relays TR2, TR3, TR4, and TR5 are connected in series with the extended normally closed contacts of the corresponding DO cards (digital output cards) in the DEH and ETS systems. This, in turn, activates the corresponding high-voltage trip solenoid valve, de-energizing it and releasing the safety oil from the entire oil circuit. The fuse FU protects the corresponding high-voltage control branch from overcurrent damage. (Digital output channel normally closed contact ETS-DO) b1 ~ETS-DO b4 The hardwired solenoid valve test signal from the ETS system indicates normal closure; the solenoid valve opens during testing within the ETS system. Normally closed contact TR. 2-1 ~TR 5-1 This is the execution contact of the trip protection main control circuit. It is normally closed and opens when the trip relay TR actuates. Digital output channel normally closed contact DEH-DO b2 ~DEH-DO b5 This is an action signal from the solenoid valves in the DEH system. They close normally and open when the system stops. The high-pressure shut-off solenoid valves AST-HPT1 to AST-HPT4 maintain a safe oil pressure when energized and depressurize to stop the system when de-energized.

[0079] Example 4

[0080] This embodiment discloses a relay control circuit for turbine tripping and overspeed protection. As a preferred embodiment of this invention, based on Embodiment 3, its high-pressure trip solenoid valve control circuit includes a manual stop button I and a manual stop button II on the control panel. The four normally closed contacts of manual stop button I and manual stop button II are connected in parallel and then in series to the high-pressure trip control branch as a manual stop control module, achieving redundant control of "the emergency stop button directly driving the solenoid valve." Specifically:

[0081] The control branch of the high-voltage shut-off solenoid valve AST-HPT1 is connected in parallel with the control branch of the high-voltage shut-off solenoid valve AST-HPT3. The normally closed contact 1-1 of the manual stop button I and the normally closed contact 2-1 of the manual stop button II on the control panel are connected in parallel to form the manual stop control module in the control branch of the high-voltage shut-off solenoid valve AST-HPT1. The normally closed contact 1-3 of the manual stop button I and the normally closed contact 2-3 of the manual stop button II on the control panel are connected in parallel to form the manual stop control module in the control branch of the high-voltage shut-off solenoid valve AST-HPT3.

[0082] The control branch of the high-voltage shut-off solenoid valve AST-HPT2 is connected in parallel with the control branch of the high-voltage shut-off solenoid valve AST-HPT4. The normally closed contacts 1-2 of the manual stop button I and 2-2 of the manual stop button II on the control panel are connected in parallel to form the manual stop control module in the control branch of the high-voltage shut-off solenoid valve AST-HPT2. The normally closed contacts 1-4 of the manual stop button I and 2-4 of the manual stop button II on the control panel are connected in parallel to form the manual stop control module in the control branch of the high-voltage shut-off solenoid valve AST-HPT4.

[0083] Normal operation: When manual stop buttons I and II on the control panel are not pressed, the normally closed contacts are closed, the high-pressure trip solenoid valve control circuit is activated, and the high-pressure trip solenoid valve is energized to maintain safe oil pressure. Emergency stop: When manual stop buttons I and II on the control panel are pressed simultaneously, all normally closed contacts open, all high-pressure trip control branches are de-energized, the high-pressure trip solenoid valve is de-energized and releases the safe oil, and closes the main steam valve and regulating steam valve. Thus, the manual stop buttons on the control panel directly act on the high-pressure trip solenoid valve control circuit and are no longer reflected in the main control circuit of the trip protection.

[0084] Example 5

[0085] This embodiment discloses a relay control circuit for turbine trip and overspeed protection. As a preferred embodiment of this invention, based on any of embodiments 1-4, the trip protection main control circuit includes several trip relays TR6, TR7, TR8, and TR9. Based on this, the main steam valve solenoid valve drive circuit is as follows... Figure 4 As shown, this includes twelve parallel main steam valve solenoid valve drive branches. The input terminals of all main steam valve solenoid valve drive branches are connected to the positive line of a DC power supply, and the output terminals are connected to the negative line. The twelve main steam valve solenoid valve drive branches are as follows:

[0086] The drive branch of the fast-closing solenoid valve FSV-MSV1 (high-pressure main steam valve 1 fast-closing) is connected in series from its input to its output with fuse FU and normally open digital output channel contact DEH-DO. k5 The fast-closing solenoid valve FSV-MSV1, fuse FU, and normally open contact TR of relay TR6. 6-1 Parallel connection to the normally open contact DEH-DO of the digital output channel k5 The two ends.

[0087] The drive branch of the fast-closing solenoid valve FSV-MSV2 (high-pressure main steam valve 2 fast-closing) is connected in series from its input to its output with fuse FU and normally open digital output channel contact DEH-DO. k6 The fast-closing solenoid valve FSV-MSV2, fuse FU, and normally open contact TR of relay TR7. 7-1 Parallel connection to the normally open contact DEH-DO of the digital output channel k6 The two ends.

[0088] The drive branch of the fast-closing solenoid valve FSV-RSV1 (medium-pressure main steam valve 1 fast-closing) is connected in series from its input to its output with fuse FU and normally open digital output channel contact DEH-DO. k7 The fast-closing solenoid valve FSV-RSV1, fuse FU, and normally open contact TR of relay TR8. 8-1 Parallel connection to the normally open contact DEH-DO of the digital output channel k7 The two ends.

[0089] The drive branch of the fast-closing solenoid valve FSV-RSV2 (medium-pressure main steam valve 2 fast-closing) is connected in series from its input to its output with fuse FU and normally open contact DEH-DO of the digital output channel. k8 The fast-closing solenoid valve FSV-RSV2, fuse FU, and normally open contact TR of relay TR9. 9-1 Parallel connection to the normally open contact DEH-DO of the digital output channel k8 The two ends.

[0090] Test the drive circuit of solenoid valve TSV-MSV1 (periodically test the operating performance of high-pressure main steam valve 1), and connect fuse FU and normally open contact DEH-DO of the digital output channel in series from its input to its output. k9 Test the solenoid valve TSV-MSV1 and the fuse FU.

[0091] Test the drive circuit of solenoid valve TSV-MSV2 (periodically test the operating performance of high-pressure main steam valve 2), and connect fuse FU and normally open contacts DEH-DO of the digital output channel in series from its input to its output. k10 Test the solenoid valve TSV-MSV2 and the fuse FU.

[0092] Test the drive circuit of solenoid valve TSV-RSV1 (periodically test the operating performance of medium-pressure main steam valve 2), and connect fuse FU and normally open contact DEH-DO of the digital output channel in series from its input to its output. k11 Test the solenoid valve TSV-RSV1 and the fuse FU.

[0093] Test the drive circuit of solenoid valve TSV-RSV2 (periodically test the operating performance of medium-pressure main steam valve 2), and connect fuse FU and normally open contact DEH-DO of the digital output channel in series from its input to its output. k12 Test the solenoid valve TSV-RSV2 and the fuse FU.

[0094] The drive branch of the fast-closing solenoid valve FSV-SPMSV1 (ultra-high pressure main steam valve 1 fast-closing) is connected in series from its input to its output with fuse FU and normally open digital output channel contact DEH-DO. k13 The fast-closing solenoid valve FSV-SPMSV1, fuse FU, and normally open contact TR of relay TR8. 8-2 Parallel connection to the normally open contact DEH-DO of the digital output channel k13 The two ends.

[0095] The drive branch of the fast-closing solenoid valve FSV-SPMSV2 (ultra-high pressure main steam valve 2 fast-closing) is connected in series from its input to its output with fuse FU and normally open digital output channel contact DEH-DO. k14 The fast-closing solenoid valve FSV-SPMSV2, fuse FU, and normally open contact TR of relay TR9. 9-2 Parallel connection to the normally open contact DEH-DO of the digital output channel k14 The two ends.

[0096] The drive branch of the test solenoid valve TSV-SPMSV1 (periodic testing of the operating performance of the ultra-high pressure main steam valve 1) is connected in series from its input to its output with fuse FU and normally open contacts DEH-DO of the digital output channel. k15Test the solenoid valve TSV-SPMSV1 and the fuse FU.

[0097] Test the drive circuit of solenoid valve TSV-SPMSV2 (periodically test the operating performance of ultra-high pressure main steam valve 2). Connect fuse FU and normally open contacts DEH-DO of the digital output channel in series from its input to its output. k16 Test the solenoid valve TSV-SPMSV2 and the fuse FU.

[0098] Based on the above structure, after each trip relay TR in the trip protection main control circuit is activated, the normally open contacts of relays TR6, TR7, TR8 and TR9 are connected in parallel with the extended normally open contacts of the corresponding DO channel (digital output card) of the DEH system, thereby activating the fast-closing solenoid valves (including fast-closing solenoid valves FSV-MSV1, FSV-MSV2, FSV-RSV1 and FSV-RSV2, and fast-closing solenoid valves FSV-SPMSV1 and FSV-SPMSV2) on the main steam valve hydraulic actuator, causing them to discharge oil and close the valve while energized.

[0099] Example 6

[0100] This embodiment discloses a relay control circuit for turbine trip and overspeed protection. As a preferred embodiment of this invention, based on any of embodiments 3-5, the trip protection main control circuit includes several trip relays TR2 and TR10. Based on this, the on / off protection control circuit II of the OPC overspeed protection circuit is as follows: Figure 5 As shown, the system includes a shutdown protection unit, a load shedding protection unit (load > 15% and generator disconnected from the grid), an OPC action protection unit (software OPC action), and a 103% overspeed protection unit connected in parallel. In the shutdown protection unit, the normally open contact TR6 of relay TR6 is connected in series from the input to the output. 6-2 and the normally open contact TR of relay TR10 10-2 .

[0101] Shutdown Protection Unit: In the main control circuit for trip protection, relay TR6 is used to drive the main steam valve solenoid valve to close quickly; in the OPC overspeed protection circuit, the normally open contact TR of relay TR6... 6-2 With relay TR10 10-2 In series connection, the shutdown protection unit is only activated when the trip protection is triggered and the relay TR10 operates simultaneously, thus avoiding malfunction of the OPC caused by a single relay failure.

[0102] OPC Action Protection Unit: Includes four normally open contacts (DEH-DO) of digital output channels connected in an "H"-shaped configuration. k (i.e. DEH-DO) k19DEH-DO k20 DEH-DO k21 and DEH-DO k22 It receives DO signals (software OPC signals) from the DEH system and implements "two-out-of-four" redundancy logic through four H-type DO channels. When a single DO channel malfunctions due to electromagnetic interference or software errors, it cannot meet the "two-out-of-four" condition, thus preventing OPC malfunctions. When two or more DO channels are outputting normally, the loop is open, ensuring reliable triggering of the OPC during actual overspeeding, solving the problem of easy malfunction of single-point OPC signals in existing technologies.

[0103] 103% Overspeed Protection Unit: The three speed measurement modules configured in the DEH system, in addition to being used in the software control loop, can output a 103% overspeed contact signal from the speed measurement module without going through the DEH system when the speed exceeds 103% of the rated value. After processing by taking two out of three, the signal is connected in parallel with the OPC action protection unit to form a "software + hardware" dual overspeed detection, ensuring that the OPC can still be triggered when the unit exceeds 103% overspeed even if the DEH system DO output card fails.

[0104] Load shedding protection unit: includes four control switches connected in an "H" shape. The four control switches are normally open contacts (DEH-DO) of two parallel digital output channels. k (i.e. DEH-DO) k17 and DEH-DO k18 The DEH system sends out two DO signals with a load greater than 15% and two parallel generator grid-connected normally closed contacts OUT-NC (i.e., OUT1-NC and OUT2-NC, from which...). Figure 6 The generator grid-connection 3-out-of-2 logic module shown closes its contacts when the generator is disconnected. The "Load > 15%" signal and the "Generator Disconnection" signal form an "H-type" parallel structure. The load shedding protection unit is activated only when both "Load > 15%" and "Generator Disconnection" occur, triggering the OPC action to close the regulating valve and suppress the speed surge caused by load shedding. Redundancy design avoids single signal failures: if one "Load > 15%" signal is interrupted due to a DO channel fault, the other signal can still trigger the OPC in conjunction with the generator disconnection contact; if a generator grid-connection contact is stuck, the 3-out-of-2 logic ensures that at least two contacts are normal before outputting a signal. The generator grid-connection signal is detected by three independent switches, and after processing by the 3-out-of-2 logic, two normally closed contacts are output. The contacts open only when two or more switches detect "grid-connection"; when the generator is disconnected, at least two switches detect "disconnection," and the contacts close, avoiding signal misinterpretation due to a single switch failure.

[0105] Example 7

[0106] This embodiment discloses a relay control circuit for turbine tripping and overspeed protection. As a preferred embodiment of this utility model, based on embodiment 6, the OPC overspeed protection circuit includes several overspeed protection control relays OR1, OR2, OR3, OR4, OR5, OR6, OR7, OR8, OR9, OR10, OR11 and OR12.

[0107] Based on this, adjust the solenoid valve drive circuit as follows: Figure 7 As shown, this includes eleven parallel solenoid valve drive branches, covering fast-closing solenoid valves (FSV) and overspeed limiting solenoid valves (OPC), used to control the emergency closure and overspeed suppression of the regulating steam valves. This circuit, through a redundant design of the normally open contact of the overspeed protection control relay OR connected in parallel with the DEH digital output card (DO channel), solves the problem of insufficient reliability in existing solenoid valve drive circuits, ensuring rapid and reliable closure of the regulating steam valve when the OPC (overspeed protection control) is activated, suppressing excessive speed rise. The input terminals of all solenoid valve drive branches are connected to the positive line of the DC power supply, and the output terminals are connected to the negative line of the DC power supply. The twelve solenoid valve drive branches are as follows:

[0108] The drive branch of the fast-closing solenoid valve FSV-CV1 (high-pressure regulating steam valve 1 fast-closing) is connected in series from its input to its output with fuse FU and normally open contact DEH-DO of the digital output channel. k23 The fast-closing solenoid valve FSV-CV1, fuse FU, and normally open contact 0R of relay OR1. 1-1 Parallel connection to the normally open contact DEH-DO of the digital output channel k23 The two ends.

[0109] The drive branch of the fast-closing solenoid valve FSV-CV2 (high-pressure regulating steam valve 2 fast-closing) is connected in series from its input to its output with fuse FU and normally open contact DEH-DO of the digital output channel. k24 The fast-closing solenoid valve FSV-CV2, fuse FU, and normally open contact 0R of relay OR2. 2-1 Parallel connection to the normally open contact DEH-DO of the digital output channel k24 The two ends.

[0110] The drive branch of the fast-closing solenoid valve FSV-PCV1 (for the quick-closing of the steam replenishment valve 1) is connected in series from its input to its output with a fuse FU and a normally open contact DEH-DO for the digital output channel. k25 The fast-closing solenoid valve FSV-PCV1, fuse FU, and normally open contact 0R of relay OR3. 3-1 Parallel connection to the normally open contact DEH-DO of the digital output channelk25 The two ends.

[0111] The drive branch of the fast-closing solenoid valve FSV-PCV2 (for the quick-closing steam valve 2) is connected in series from its input to its output with fuse FU and normally open digital output channel contact DEH-DO. k26 The fast-closing solenoid valve FSV-PCV2, fuse FU, and normally open contact 0R of relay OR4. 4-1 Parallel connection to the normally open contact DEH-DO of the digital output channel k26 The two ends.

[0112] The drive branch of the fast-closing solenoid valve FSV-ICV1 (medium-pressure regulating steam valve 1 fast-closing) is connected in series from its input to its output with fuse FU and normally open contact DEH-DO of the digital output channel. k27 The fast-closing solenoid valve FSV-ICV1, fuse FU, and normally open contact 0R of relay OR5. 5-1 Parallel connection to the normally open contact DEH-DO of the digital output channel k27 The two ends.

[0113] The drive branch of the fast-closing solenoid valve FSV-ICV2 (medium-pressure regulating steam valve 2 fast-closing) is connected in series from its input to its output with fuse FU and normally open contact DEH-DO of the digital output channel. k28 The fast-closing solenoid valve FSV-ICV2, fuse FU, and normally open contact 0R of relay OR6. 6-1 Parallel connection to the normally open contact DEH-DO of the digital output channel k28 The two ends.

[0114] The overspeed limiting solenoid valve OPC-HPT1 drive branch (overspeed limiting, auxiliary suppression of excessive speed rise) is connected in series from its input to its output with fuse FU and normally open digital output channel contact DEH-DO. k29 The overspeed limiting solenoid valve OPC-HPT1 and fuse FU, and the normally open contact 0R of relay 0R7. 7-1 Parallel connection to the normally open contact DEH-DO of the digital output channel k29 The two ends.

[0115] The overspeed limiting solenoid valve OPC-HPT2 drive branch (overspeed limiting, auxiliary suppression of excessive speed rise) is connected in series from its input to its output with fuse FU and normally open contact DEH-DO of the digital output channel. k30 The overspeed limiting solenoid valve OPC-HPT2 and fuse FU, and the normally open contact 0R of relay 0R8. 8-1 Parallel connection to the normally open contact DEH-DO of the digital output channel k30 The two ends.

[0116] The drive branch of the FSV-RB1 rotary diaphragm quick-closing solenoid valve (rotary diaphragm quick-closing) is connected in series from its input to its output with a fuse FU and a normally open contact DEH-DO for the digital output channel. k31 Rotary baffle quick-closing solenoid valve FSV-RB1 and fuse FU, normally open contact 0R of relay 0R9 9-1 Parallel connection to the normally open contact DEH-DO of the digital output channel k31 The two ends.

[0117] The drive branch of the fast-closing solenoid valve FSV-SPCV1 (ultra-high pressure regulating steam valve 1 fast-closing) is connected in series from its input to its output with fuse FU and normally open contact DEH-DO of the digital output channel. k32 The fast-closing solenoid valve FSV-SPCV1, fuse FU, and normally open contact 0R of relay OR11. 11-1 Parallel connection to the normally open contact DEH-DO of the digital output channel k32 The two ends.

[0118] The drive branch of the fast-closing solenoid valve FSV-SPCV2 (ultra-high pressure regulating steam valve 2 fast-closing) is connected in series from its input to its output with fuse FU and normally open contact DEH-DO of the digital output channel. k33 The fast-closing solenoid valve FSV-SPCV2, fuse FU, and normally open contact 0R12 of relay 0R 12-1 Parallel connection to the normally open contact DEH-DO of the digital output channel k33 The two ends.

[0119] Additionally, the normally open contact 0R of relay 0R10 10-1 and 0R 10-2 Connection structure such as Figure 7 As shown, normally open contact OR 10-1 The normally open contact DEH-DO of the digital output channel of the control fast-closing solenoid valve FSV-BV1 (butterfly valve 1 fast-closing) is connected in parallel. k34 Both ends, normally open contact 0R 10-2 The normally open contact DEH-DO of the digital output channel of the control fast-closing solenoid valve FSV-BV2 (butterfly valve 2 fast-closing) is connected in parallel. k35 Both ends.

[0120] In this technical solution, the normally open contact of the overspeed protection control relay OR and the open contact of the DEH DO card output form a "dual drive" mechanism. Under normal conditions, the DO signal output by the DEH system drives the corresponding solenoid valve. When the OPC overspeed protection is triggered, the overspeed protection control relay OR operates, and its normally open contact closes to drive the corresponding solenoid valve. Even if the DEH DO channel cannot output due to a fault, the corresponding regulating valve solenoid valve drive branch can still be directly connected through the contact of the overspeed protection control relay OR, thereby ensuring that the regulating valve is closed.

Claims

1. A relay control circuit for turbine trip and overspeed protection, characterized in that, It includes the main control circuit for trip protection, the control circuit for high-pressure trip solenoid valve, the control circuit for mechanical shutdown electromagnet, the drive circuit for main steam valve solenoid valve, the OPC overspeed protection circuit, and the drive circuit for regulating valve solenoid valve. The trip protection main control circuit includes a switching protection control circuit I and several trip relays TR; the input terminals of all trip relay TR coils are connected to the positive line of the DC power supply through the switching protection control circuit I, and the output terminals are connected to the negative line of the DC power supply; the contacts of each trip relay TR are distributed and connected to the high-voltage trip solenoid valve control circuit, the mechanical shutdown solenoid control circuit, the main steam valve solenoid valve drive circuit, and the OPC overspeed protection circuit; The on-off protection control circuit I comprises DEH shutdown protection unit, 110% overspeed protection unit, ETS shutdown protection unit and extension item shutdown protection unit which are connected in parallel with each other; the DEH shutdown protection unit comprises four digital output channel normally open contacts connected in "H" type architecture ​ The ETS shutdown protection unit includes four digital output channels with normally open contacts in an "H" architecture ; The OPC overspeed protection circuit includes a switching protection control circuit II and several overspeed protection control relays OR; the input terminals of all overspeed protection control relays OR coils are connected to the positive line of the DC power supply through the switching protection control circuit II, and the output terminals are connected to the negative line of the DC power supply; the contacts of each overspeed protection control relay OR are distributed and connected in the control valve solenoid valve drive circuit.

2. A relay control circuit for turbine trip and overspeed protection as claimed in claim 1 wherein, The trip relays TR in the main control circuit of the trip protection include relays TR1, TR2, TR3, TR4, TR5, TR6, TR7, TR8, TR9 and TR10.

3. A relay control circuit for turbine trip and overspeed protection as recited in claim 2, wherein, The mechanical stop electromagnet control loop input end is connected with the positive line of the direct current power supply, and the output end is connected with the negative line of the direct current power supply; the normally open contact of the relay TR1 The mechanical stop electromagnet control loop is accessed, and the coil input end of the relay TR1 is accessed with a digital output channel normally closed contact .

4. A relay control circuit for turbine trip and overspeed protection as recited in claim 2, wherein, The high-pressure cut-off electromagnetic valve control circuit comprises four high-pressure cut-off control branches, respectively high-pressure cut-off electromagnetic valve control branch, high-pressure cut-off electromagnetic valve control branch, high-pressure cut-off electromagnetic valve control branch, high-pressure cut-off electromagnetic valve control branch The input terminals of all high-voltage shutdown control branches are connected to the positive power line of the high-voltage shutdown solenoid valve, and the output terminals are connected to the negative power line of the high-voltage shutdown solenoid valve. All high shielding control branches are respectively connected with digital output channel normally closed contact , digital output channel normally closed contact and manual stop control module Normally closed contacts of relays TR2, TR3, TR4 and TR5 , , and Each of the four high-shading control branches is connected in a one-to-one correspondence.

5. A relay control circuit for turbine trip and overspeed protection as recited in claim 2, wherein, The high-voltage shut-off solenoid valve control circuit includes a manual stop button I and a manual stop button II on the control panel. High-pressure shut-off solenoid valve Control branch and high-voltage shut-off solenoid valve The control branches are connected in parallel. The normally closed contact 1-1 of the manual stop button I on the control panel and the normally closed contact 2-1 of the manual stop button II on the control panel are connected in parallel to form a high-voltage shut-off solenoid valve. In the control branch, the normally closed contacts 1-3 of the manual stop button I on the control panel and the normally closed contacts 2-3 of the manual stop button II on the control panel are connected in parallel to form a high-voltage shut-off solenoid valve. Manual stop control module in the control branch; High-pressure shut-off solenoid valve Control branch and high-voltage shut-off solenoid valve The control branches are connected in parallel. The normally closed contacts 1-2 of the manual stop button I on the control panel and the normally closed contacts 2-2 of the manual stop button II on the control panel are connected in parallel to form a high-voltage shut-off solenoid valve. In the control branch, the normally closed contacts 1-4 of the manual stop button I on the control panel and the normally closed contacts 2-4 of the manual stop button II on the control panel are connected in parallel to form a high-voltage shut-off solenoid valve. Manual stop control module for control branch.

6. The relay control circuit for turbine tripping and overspeed protection as described in claim 2, characterized in that, The main steam valve solenoid valve drive circuit includes twelve parallel main steam valve solenoid valve drive branches, namely, the drive branch for fast-closing solenoid valve FSV-MSV1, the drive branch for fast-closing solenoid valve FSV-MSV2, the drive branch for fast-closing solenoid valve FSV-RSV1, the drive branch for fast-closing solenoid valve FSV-RSV2, the drive branch for test solenoid valve TSV-MSV1, the drive branch for test solenoid valve TSV-MSV2, the drive branch for test solenoid valve TSV-RSV1, the drive branch for test solenoid valve TSV-RSV2, the drive branch for fast-closing solenoid valve FSV-SPMSV1, the drive branch for fast-closing solenoid valve FSV-SPMSV2, the drive branch for test solenoid valve TSV-SPMSV1, and the drive branch for test solenoid valve TSV-SPMSV2.

7. A relay control circuit for turbine trip and overspeed protection as recited in claim 6, wherein, A digital output channel normally open contact is connected in each of the main valve solenoid drive branches ; normally open contact of the relay TR6 normally open contact of the digital output channel in parallel with the fast closing electromagnetic valve FSV-MSV1 drive branch both ends; normally open contact of the relay TR7 normally open contact of the digital output channel in parallel with the fast shut-off solenoid valve FSV-MSV2 drive branch both ends; normally open contact of the relay TR8 normally open contact of the digital output channel in parallel with the fast closing electromagnetic valve FSV-RSV1 drive branch both ends; normally open contact of the relay TR9 normally open contact of the digital output channel in parallel with the fast closing electromagnetic valve FSV-RSV2 drive branch both ends; normally open contact of the relay TR8 normally open contact of the digital output channel in parallel with the fast shut-off solenoid valve FSV-SPMSV1 drive branch both ends; Normally open contact of relay TR9 Normally open contact of digital output channel in parallel to fast shut-off solenoid valve FSV-SPMSV2 drive branch Both ends.

8. A relay control circuit for turbine trip and overspeed protection as recited in claim 2, wherein, The OPC overspeed protection circuit II includes a shutdown protection unit, a load shedding protection unit, an OPC action protection unit, and a 103% overspeed protection unit connected in parallel; and normally open contacts of relays TR6 and TR10. and They are connected in series in the shutdown protection unit.

9. A relay control circuit for turbine trip and overspeed protection as recited in claim 8, wherein, The OPC action protection unit includes four digital output channel normally open contacts connected in an "H" architecture .

10. A relay control circuit for turbine trip and overspeed protection as recited in claim 8, wherein, The load shedding protection unit includes four control switches connected in an "H"-shaped configuration; the four control switches are normally open contacts of two parallel digital output channels. And two parallel generators connected to the grid via normally closed contacts OUT-NC.

11. A relay control circuit for turbine trip and overspeed protection as defined in claim 8 wherein, The OPC overspeed protection circuit includes several overspeed protection control relays OR, namely relays OR1, OR2, OR3, OR4, OR5, OR6, OR7, OR8, OR9, OR10, OR11 and OR12.

12. A relay control circuit for turbine trip and overspeed protection as defined in claim 11 wherein, The control valve solenoid valve drive circuit includes eleven parallel control valve solenoid valve drive branches, namely, the fast-closing solenoid valve FSV-CV1 drive branch, the fast-closing solenoid valve FSV-CV2 drive branch, the fast-closing solenoid valve FSV-PCV1 drive branch, the fast-closing solenoid valve FSV-PCV2 drive branch, the fast-closing solenoid valve FSV-ICV1 drive branch, the fast-closing solenoid valve FSV-ICV2 drive branch, the overspeed limiting solenoid valve OPC-HPT1 drive branch, the overspeed limiting solenoid valve OPC-HPT2 drive branch, the rotating partition fast-closing solenoid valve FSV-RB1 drive branch, the fast-closing solenoid valve FSV-SPCV1 drive branch, and the fast-closing solenoid valve FSV-SPCV2 drive branch.

13. A relay control circuit for turbine trip and overspeed protection as defined in claim 11 wherein, Each of the aforementioned control valve solenoid drive circuits is connected to a normally open digital output channel contact. Normally open contacts of relays OR1, OR2, OR3, OR4, OR5, OR6, OR7, OR8, OR9, OR11, and OR12 , , , , , , , , , and The normally open contacts of the digital output channels in each of the eleven control valve solenoid drive branches correspond one-to-one. Both ends.

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