A braking control circuit structure suitable for hydro-generator sets

Abstract

This invention discloses a braking control circuit structure suitable for hydroelectric generator sets, relating to the field of hydropower technology. The main power supply of this invention uses two different power sources and is equipped with a dual-power automatic transfer switch. On the main circuit, a standby oil pump motor is installed, and each main circuit has its own independent circuit breaker and contactor. For the solenoid valves and PLC power supply, 220VAC and 220VDC power supplies are used, with a dual-power automatic converter to ensure power supply reliability. A DC redundancy module is also included to decouple the two power sources, thereby ensuring high system availability and preventing system shutdown in the event of a power failure in one source, thus enhancing system stability. This invention improves the fault tolerance and operational stability of the braking system by optimizing power supply configuration and circuit design.

Description

Technical Field

[0001] This invention relates to the field of hydropower generation technology, particularly to the field of braking control technology for hydro-generator sets, and more specifically to a braking control circuit structure suitable for hydro-generator sets. Background Technology

[0002] In the field of hydropower technology, the braking and electrical control system of the turbine generator and generator motor is a key component in ensuring the safe shutdown of the unit. The reliability of its power supply and circuit control directly determines the stability of the braking process. Currently, the braking systems of domestic hydropower units generally adopt pneumatic braking, and their electrical control systems have many limitations in power supply configuration and circuit design, making it difficult to meet the requirements of high-reliability operation.

[0003] In terms of power supply circuit design for solenoid valves, PLCs, sensors, etc., existing braking electronic control systems mostly use only DC 220V power supply, which is a single power supply type and lacks redundant power supply, automatic switching mechanism, UPS uninterruptible power supply, and battery module. When this power supply is interrupted due to line faults or other reasons, the braking system will directly lose power support, resulting in complete failure of the braking function and inability to meet emergency shutdown requirements.

[0004] The original braking system is a pneumatic braking system and does not have the main circuit described in this invention.

[0005] The aforementioned deficiencies result in significant shortcomings in the existing braking electronic control system in terms of power supply reliability, circuit safety, and control accuracy. There is an urgent need to improve the braking system's fault resistance and operational stability by optimizing power supply configuration and circuit design. Summary of the Invention

[0006] To overcome the defects and shortcomings of the existing technology, this invention provides a braking control circuit structure suitable for hydro-generator sets. The purpose of this invention is to solve the problems of insufficient fault resistance and operational stability of existing braking electronic control systems. This invention uses two different power sources for the main power supply and is equipped with a dual-power automatic transfer switch. On the main circuit, a standby oil pump motor is installed, and each main circuit has its own independent circuit breaker and contactor. For the power supply of solenoid valves, PLCs, sensors, etc., 220VAC and 220VDC power supplies are used, with a dual-power automatic converter to ensure power supply reliability. A DC redundancy module is also included to decouple the two power sources, thereby ensuring high system availability and preventing system shutdown in the event of a power failure in one source, thus enhancing system stability. Furthermore, a DC UPS module is included for uninterrupted voltage regulation and filtering to ensure uninterrupted power supply. The DC UPS module is also equipped with a battery to ensure that the solenoid valves always have a 24VDC power supply even when both AC and DC power are interrupted on-site.

[0007] To address the problems existing in the prior art, the present invention is achieved through the following technical solution.

[0008] This invention provides a braking control circuit structure suitable for hydro-generator sets, including a main power supply circuit, an oil pump motor main circuit, a solenoid valve control circuit, and a PLC control module;

[0009] The main power supply circuit is powered by two power supply circuits from different sources. These two power supply circuits are connected to the main power supply circuit through a dual power automatic transfer switch. The main power supply circuit is equipped with a main circuit breaker that controls the on and off of the main power supply circuit.

[0010] The main circuit of the oil pump motor includes a first oil pump motor main circuit and a second oil pump motor main circuit, one for use and one for standby. The first oil pump motor main circuit and the second oil pump motor main circuit are connected in parallel to the main power supply circuit and are powered by the main power supply circuit. A first circuit breaker, a first contactor, a first thermal relay, and a first oil pump motor are connected in series in the first oil pump motor main circuit. A second circuit breaker, a second contactor, a second thermal relay, and a second oil pump motor are connected in series in the second oil pump motor main circuit. Both the first contactor and the second contactor are connected to the PLC control module and are controlled by the PLC control module to switch on and off. The normally open contacts of the first thermal relay and the second thermal relay are connected to the PLC control module to transmit the closing signal of the normally open contacts after the oil pump motor is overloaded to the PLC control module. The normally closed contacts of the first thermal relay and the second thermal relay are connected in series in the first oil pump motor main circuit and the second oil pump motor main circuit, respectively.

[0011] The solenoid valve control circuit provides power to the PLC control module and the solenoid valve group of the brake hydraulic system. The solenoid valve control circuit includes a 220V AC main power supply circuit, a 220V DC backup circuit consisting of an inverter, a dual-power automatic converter, a first power module, a second power module, a DC redundancy module, and a DC UPS module. The 220V AC main power supply circuit is connected to the first input terminal of the dual-power automatic converter, and the 220V DC backup circuit is connected to the second input terminal of the dual-power automatic converter. The first and second power modules are connected in parallel to the output circuit of the dual-power automatic converter. The positive output terminals of the first and second power modules are connected to the DC redundancy module, and the positive output terminal of the DC redundancy module is connected to the positive input terminal of the DC UPS module. The negative output terminals of the first, second, and DC redundancy modules are all connected to the negative input terminal of the DC UPS module. The output terminal of the DC UPS is connected to the PLC control module and each solenoid valve in the solenoid valve group. The solenoid valve group is controlled by the PLC control module, which controls the on / off state of each solenoid valve.

[0012] In the main power supply circuit, the main circuit breaker is normally closed and is only opened during circuit maintenance and other operating conditions. It is used to isolate the power supply during maintenance, ensure the safety of maintenance personnel, and meet electrical safety standards.

[0013] In the main circuit of the oil pump motor, the first and second circuit breakers are normally closed and used for short-circuit protection. They automatically trip when a short-circuit fault occurs, have high breaking capacity, and can quickly cut off the fault current to prevent the accident from escalating. Moreover, they ensure that all three phases are disconnected at the same time to prevent residual voltage from causing secondary impact on the equipment. In view of the characteristics of large starting current and easy stalling of three-phase motors, the first and second circuit breakers have a delayed tripping function to avoid malfunction.

[0014] In the main circuit of the oil pump motor, both the first and second contactors are connected to the PLC control module and are controlled by the PLC control module to open and close. They are generally normally open and are only closed when the oil pump motor needs to be started.

[0015] In the main circuit of the oil pump motor, the first and second thermal relays are connected to the PLC control module via their normally open contacts to prevent motor overload. When the oil pump motor is overloaded, the normally open contacts close, transmitting a signal to the PLC control module. The normally closed contacts of the first and second thermal relays are connected in series in the first and second main circuits of the oil pump motor, respectively. When one of the motors experiences overcurrent or overload, the normally closed contact of the thermal relay in that circuit automatically opens, and the normally open contact automatically closes. After the normally open contact closes, the signal enters the PLC control module, which then issues an alarm signal.

[0016] In the solenoid valve control circuit, the dual-power automatic converter automatically switches to the backup circuit when the primary 220V AC power supply circuit fails, ensuring the reliability and continuity of power supply. The first and second power modules serve as backups for each other, both powered by DC redundant modules to prevent the DC redundant modules from being without input power in case of a fault. The DC redundant modules provide electrical isolation and decoupling between the first and second power modules, preventing a fault in one path from propagating to the other, ensuring that the two power supplies do not interfere with each other, eliminating the effects of circulating currents, and ensuring that the system will not shut down when one power source fails. They also provide current sharing, load balancing, and voltage stability. Simultaneously, the DC redundant modules convert 220V AC to 24V DC output to power the DC UPS module.

[0017] More preferably, the solenoid valve assembly of the brake hydraulic system is installed on the oil supply line and the oil return line between the oil tank and the brake. The solenoid valve assembly includes an upper solenoid valve and a lower solenoid valve. The upper solenoid valve is installed on the oil supply line, and the lower solenoid valve is installed on the oil return line. The input end of the first oil pump motor is connected to the oil tank, and the output end is connected to the oil supply line. The input end of the second oil pump motor is connected to the oil tank, and the output end of the second oil pump motor is connected to the oil supply line. Both the upper and lower solenoid valves are connected to a PLC control module for control.

[0018] More preferably, the PLC control module is communicatively connected to the LCU monitoring system of the braking system. After receiving the braking signal from the LCU monitoring system, the PLC control module controls the first contactor or the second contactor in the main circuit of the first oil pump motor or the main circuit of the second oil pump motor to close; controls the upper brake solenoid valve to open, the oil supply line to supply oil to the brake; controls the lower brake solenoid valve to close, the return oil line to disconnect, and braking is performed.

[0019] More preferably, the gate-opening solenoid valve is a single-coil normally closed solenoid valve that is fully reset when energized and de-energized; the gate-releasing solenoid valve is a single-coil normally open solenoid valve that is fully reset when energized and de-energized.

[0020] More preferably, both the gate-opening solenoid valve and the gate-releasing solenoid valve are direct-acting solenoid valves with zero leakage when closed and zero leakage at the valve stem interface.

[0021] More preferably, an accumulator is also installed on the oil supply line, the accumulator is equipped with a pressure relief line, the pressure relief line is equipped with a pressure relief solenoid valve, and the pressure relief line is connected to the return oil line; the pressure relief solenoid valve is controlled and connected to the PLC control module; a pressure sensor is also installed on the accumulator, and the pressure sensor is electrically connected to the PLC control module.

[0022] More preferably, the pressure relief solenoid valve is a single-coil normally open solenoid valve that closes when energized and fully resets when de-energized.

[0023] Preferably, a third circuit breaker is installed on the 220V AC mains power supply circuit, and a fourth circuit breaker and a DC / AC inverter are connected in series on the backup circuit. The third and fourth circuit breakers are normally closed circuit breakers, manually closed, and can serve as isolation power supplies to ensure that downstream components and equipment are not energized during debugging and maintenance, thus ensuring the safety of maintenance personnel; they can also serve as automatic trip protection switches to prevent the escalation of accidents when short circuits or other faults occur in downstream components.

[0024] More preferably, a power monitoring module is connected in parallel in the connection circuit between the first power module, the second power module, the redundant module, and the DC UPS module. This power monitoring module is connected to the PLC control module, which judges the fault signals of the DC UPS module collected by the power monitoring module. If a fault is determined in the DC UPS module, the PLC control module sends the fault signal to the LCU monitoring system. The power monitoring module monitors the DC UPS module to ensure its power supply reliability. When the DC redundant module fails, a power fault alarm will occur. This alarm signal is sent via the PLC control module to the LCU monitoring system of the braking system, providing a signal indicating whether braking is appropriate.

[0025] More preferably, the DC UPS module is connected to a power supply battery, so that when both the 220V AC power supply circuit and the 220V DC power supply circuit in the solenoid valve control circuit are de-energized, the power supply battery supplies power to the solenoid valve.

[0026] More preferably, the main power supply circuit also includes a tank heater circuit connected in parallel.

[0027] More preferably, the oil tank heater circuit includes a fifth circuit breaker, an NC regulating switch, and a heater. The fifth circuit breaker is used to control the on / off state of the oil tank heater circuit. The NC regulating switch and the heater are connected in series in the oil tank heater circuit. When the oil temperature reaches the specified range, the NC regulating switch automatically disconnects.

[0028] More preferably, the heater is equipped with a temperature sensing resistor.

[0029] The fuel tank heater circuit prevents the fuel tank temperature from becoming too low or too high. The heater's built-in temperature sensor measures the fuel temperature, automatically heating when the temperature is too low and automatically disconnecting when the temperature returns to normal. The NC regulating switch is generally in the normally open state, while the fifth circuit breaker is in the normally closed state. The fifth circuit breaker serves as an electrical isolation power supply during maintenance of the heater and NC regulating switch. A separate fuel temperature and level fault monitoring sensor is installed inside the fuel tank. Upon detecting a fault, the PLC control module outputs a fault signal to the LCU monitoring system.

[0030] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0031] 1. This invention employs two power supply circuits from different sources and configures a dual-power automatic transfer switch to construct a highly reliable power redundancy architecture. When one power source is interrupted due to sudden events such as grid fluctuations or line faults, the transfer switch can automatically switch to the other power source within milliseconds, fundamentally avoiding the overall power loss of the braking system caused by a single power source failure and ensuring continuous power supply during emergency shutdowns. The main circuit breaker is normally closed and only opens during maintenance, which not only meets the maintenance isolation requirements of electrical safety regulations but also reduces ineffective power supply under non-braking conditions, lowers the risk of aging of circuit components due to prolonged energization, and avoids energy waste.

[0032] 2. This invention employs a standby oil pump motor main circuit (first and second oil pump motors) with one operating and one standby circuit to achieve physical isolation through independent circuit breakers (first and second circuit breakers), contactors (first and second contactors), and thermal relays (first and second thermal relays). When a single unit experiences overcurrent, overload, or short circuit faults, the PLC can immediately switch to the standby circuit, preventing pressure build-up failure in the braking system and ensuring that the unit shutdown process is not delayed.

[0033] 3. The first and second circuit breakers of this invention have high breaking capacity and delayed tripping function, which can quickly cut off the short-circuit fault current, ensure simultaneous tripping of the three phases, prevent secondary impact of residual voltage, and avoid malfunction caused by the inrush current when the motor starts; the thermal relay directly cuts off the overload circuit through the normally closed contact and transmits an alarm signal to the PLC through the normally open contact, realizing the linkage between overload protection and fault warning, effectively preventing the motor from burning out.

[0034] 4. The first and second contactors of the present invention are controlled by PLC to be on and off (normally open), and are closed only when braking is required, avoiding unexpected start-up caused by misoperation or circuit interference in traditional systems, and eliminating the risk of the unit being accidentally braked at high speed.

[0035] 5. The solenoid valve control circuit of this invention adopts a multi-level power supply redundancy design. The 220V AC main power supply and the 220V DC backup power supply are seamlessly switched through a dual power automatic converter. Combined with the mutual backup design of the first and second power modules, this ensures the continuity of power supply to the solenoid valve, PLC, and pressure sensors. The DC redundancy module achieves electrical isolation and decoupling of the two power supplies, eliminating circulating current interference. Even if one power supply fails, it will not affect the other, ensuring stable operation of the system even in the event of a single power failure. The DC UPS module and its matching battery provide uninterrupted regulated power. Even if both AC and DC power supplies are interrupted, the battery module can still maintain a 24V DC emergency power supply to the solenoid valve, preventing brake valve failure. The third and fourth circuit breakers serve as isolation protection components, facilitating maintenance of downstream equipment (ensuring no live operation) and automatically tripping in the event of a short circuit to prevent the fault from escalating. The power monitoring module monitors the DC UPS status in real time. In the event of a fault, it sends an alarm signal to the LCU via the PLC, providing a basis for braking decisions and preventing the braking system from operating with a fault.

[0036] 6. After receiving the braking signal from the LCU, the PLC of this invention starts the oil pump motor through a control contactor, simultaneously driving the upper solenoid valve (energized) and the lower solenoid valve (energized), thus opening the oil supply path and closing the oil return path. This, combined with real-time pressure monitoring by a pressure sensor on the oil supply line, ensures stable maintenance of the braking force after reaching the set value, improving braking accuracy. The upper and lower solenoid valves adopt a direct-acting design, with zero leakage when closed (including the valve stem interface), avoiding hydraulic oil waste and pressure loss. The single-coil normally closed / normally open characteristic ensures automatic reset (upper valve closed, lower valve open) upon power failure, preventing braking abnormalities caused by sudden power outages. The accumulator maintains pressure through a normally closed pressure relief solenoid valve, which also allows for safe pressure relief during maintenance. The pressure sensor on the accumulator is linked to the PLC, automatically charging according to the set value to ensure pressure stability during braking. Simultaneously, the pressure relief solenoid valve only releases pressure via PLC control after a 30-minute power outage in the entire system, preventing prolonged high pressure in the oil system.

[0037] 7. The present invention also includes an auxiliary circuit, which automatically adjusts the oil temperature by means of the linkage between the fifth circuit breaker, the NC regulating switch and the heater (heating when the temperature is too low and disconnecting when it is normal), thus preventing the hydraulic oil from affecting the braking performance due to abnormal viscosity; the heater is not connected to the PLC, ensuring that the adjustment logic is independent and reliable.

[0038] 8. The present invention is also equipped with a low liquid level and high oil temperature signal switch; when a low liquid level or high oil temperature abnormal signal occurs, it is uploaded to the local display screen via PLC, and then uploaded to LCU via PLC to realize fault early warning.

[0039] 9. This invention can realize full-link status monitoring, from power status (DC UPS, redundant modules), motor overload (thermal relay) to oil temperature and oil level (independent sensor), all fault signals are collected by PLC and uploaded to LCU, forming a closed-loop control of "fault-alarm-interlock", avoiding braking with faults and reducing the risk of accidents.

[0040] 10. This invention, through a multi-layered design of "power redundancy + circuit isolation + precise control + full-state monitoring," completely solves the defects of traditional braking systems, such as single power supply, insufficient protection, low control precision, and high-speed false activation. At the power supply level, it achieves "uninterrupted operation even in the event of a single power outage," with dual power supply switching, UPS, and battery backup ensuring zero power interruption. At the execution level, it achieves "no failure even in the event of a single point of failure," with redundant design and independent protection for the oil pump motor and solenoid valves ensuring controllable braking. At the control level, it achieves "zero risk of misoperation," with logical linkage between contactors and solenoid valves and automatic reset upon power failure preventing unexpected braking. The overall system significantly improves the safety and stability of the hydro-generator unit's braking process, providing a highly reliable circuit guarantee under all operating conditions for safe unit shutdown. Attached Figure Description

[0041] Figure 1 This is a structural diagram of the braking control circuit of the turbine generator set of the present invention;

[0042] Figure 2 This is a schematic diagram of the overall power supply circuit structure of the present invention;

[0043] Figure 3 This is a circuit diagram of the main circuit of the oil pump motor of the present invention;

[0044] Figure 4 This is a circuit diagram of the solenoid valve control loop of the present invention;

[0045] Figure 5 This is a diagram of the dual power supply structure in the solenoid valve control circuit of the present invention;

[0046] Figure 6 This is a structural diagram of the dual-power automatic converter output circuit in the solenoid valve control circuit of the present invention;

[0047] Figure 7 This is a structural diagram of the braking hydraulic system of the present invention;

[0048] Figure 8 This is a circuit diagram of the oil tank heater of the present invention;

[0049] Figure reference numerals: 1. Main power supply circuit; 2. Oil pump motor main circuit; 3. Solenoid valve control circuit; 4. Dual power automatic transfer switch; 5. Main circuit breaker; 6. First oil pump motor main circuit; 7. Second oil pump motor main circuit; 8. First circuit breaker; 9. First contactor; 10. First thermal relay; 11. First oil pump motor; 12. Second circuit breaker; 13. Second contactor; 14. Second thermal relay; 15. Second oil pump motor; 16. 220V AC common power supply circuit; 17. Backup circuit; 18. Dual power automatic transfer switch; 19. First power module; 20. Second power module; 21. DC redundancy module; 22. DC... UPS module, 23. Fuel tank, 24. Brake, 25. Fuel supply line, 26. Fuel return line, 27. Opening solenoid valve, 28. Releasing solenoid valve, 29. Accumulator, 30. Pressure relief line, 31. Pressure relief solenoid valve, 32. Third circuit breaker, 33. Fourth circuit breaker, 34. DC / AC inverter, 35. Power monitoring module, 36. Power supply battery, 37. Fuel tank heater circuit, 38. Fifth circuit breaker, 39. NC regulating switch, 40. Heater. Detailed Implementation

[0050] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] Example 1

[0052] As a preferred embodiment of the present invention, please refer to the appendix to the specification. Figure 1 As shown in the figure, this embodiment discloses a braking control circuit structure suitable for hydro-generator sets, including a main power supply circuit 1, an oil pump motor main circuit 2, a solenoid valve control circuit 3, and a PLC control module (not shown in the figure).

[0053] Refer to the instruction manual appendix Figure 2As shown, the main power supply circuit 1 adopts a dual-path independent power supply architecture. The two power sources are from two different power supply circuits (such as different bus sections of the plant's low-voltage section). They are connected to the main circuit of the system through a dual-power automatic transfer switch 4 (such as the ATSE series, with a switching time ≤50ms). That is, the two different power supply circuits are connected to the main power supply circuit 1 through the dual-power automatic transfer switch 4. The main power supply circuit 1 is equipped with a main circuit breaker 5 that controls the on / off state of the main power supply circuit 1. In the main power supply circuit 1, the main circuit breaker 5 is normally closed and is only opened during circuit maintenance and other operating conditions. It is used to isolate the power supply during maintenance, ensure the safety of maintenance personnel, and meet electrical safety regulations.

[0054] The core advantage of the above design is that when any power supply is interrupted due to grid fluctuations, line faults, or equipment maintenance, the dual power automatic transfer switch 4 can instantly switch to another power supply, preventing the braking system from failing due to power loss and ensuring power continuity during emergency shutdowns from the source. The "normal closing and on-demand opening" logic of the main circuit breaker 5 reduces ineffective power supply under non-braking conditions, reduces the risk of aging of circuit components due to long-term energization, and saves energy.

[0055] Refer to the instruction manual appendix Figure 3 As shown, the main circuit 2 of the oil pump motor includes a first oil pump motor main circuit 6 (one in use and one in standby) and a second oil pump motor main circuit 7. The first oil pump motor main circuit 6 and the second oil pump motor main circuit 7 are connected in parallel to the main power supply circuit 1 and are powered by the main power supply circuit 1. The first oil pump motor main circuit 6 is connected in series with a first circuit breaker 8, a first contactor 9, a first thermal relay 10, and a first oil pump motor 11. The second oil pump motor main circuit 7 is connected in series with a second circuit breaker 12, a second contactor 13, a second thermal relay 14, and a second oil pump motor 15. The first contactor 9 and the second contactor 13 are both connected to the PLC control module and are controlled by the PLC control module to switch on and off. The normally open contacts of the first thermal relay 10 and the second thermal relay 14 are connected to the PLC control module to transmit the closing signal of the normally open contacts after the oil pump motor is overloaded to the PLC control module. The normally closed contacts of the first thermal relay 10 and the second thermal relay 14 are connected in series in the first oil pump motor main circuit 6 and the second oil pump motor main circuit 7, respectively.

[0056] In the main circuit 2 of the oil pump motor mentioned above, the first circuit breaker 8 and the second circuit breaker 12 are normally closed and used for short-circuit protection. They automatically trip when a short-circuit fault occurs. They have high breaking capacity (breaking capacity ≥10kA) and three-phase simultaneous breaking characteristics, which can quickly cut off the short-circuit fault current and prevent the residual voltage from having a secondary impact on the motor. In view of the characteristics of three-phase motors, such as large starting current (about 5-7 times the rated current) and easy stalling, the circuit breaker has a built-in time delay tripping function (the delay time can be set to 0.1-1s) to avoid false tripping caused by the inrush current at the moment of starting.

[0057] In the main circuit 2 of the oil pump motor described above, the first contactor 9 and the second contactor 13 are both connected to the PLC control module and controlled by the PLC control module to switch on and off. They are generally normally open and only close when the PLC receives a braking command to drive the corresponding oil pump motor to start. The two contactors are interlocked (the PLC program is set with the logic "the second contactor 13 is prohibited from operating when the first contactor 9 is closed") to prevent overload caused by the simultaneous start of the two motors.

[0058] In the aforementioned main circuit 2 of the oil pump motor, the normally open contacts of the first thermal relay 10 and the second thermal relay 14 are connected to the PLC control module to prevent motor overload. When the oil pump motor is overloaded, the normally open contacts close and transmit the signal to the PLC control module. The normally closed contacts of the first thermal relay 10 and the second thermal relay 14 are connected in series in the first oil pump motor main circuit 6 and the second oil pump motor main circuit 7, respectively. When one of the motors experiences overcurrent or overload, the normally closed contact of the thermal relay in that circuit automatically opens, and the normally open contact automatically closes. After the normally open contact closes, the signal enters the PLC control module, which then issues an alarm signal to prevent the braking system from failing to build up pressure.

[0059] Refer to the instruction manual appendix Figure 4 Appendix Figure 5 and attached Figure 6 As shown, the solenoid valve control circuit 3 supplies power to the solenoid valve group of the PLC control module and the brake hydraulic system. It adopts a design of "dual power supply switching + redundancy conversion + uninterrupted power supply", and its specific configuration is as follows:

[0060] The solenoid valve control circuit 3 includes a 220V AC main power supply circuit 16, a 220V DC backup circuit 17 composed of an inverter, a dual-power automatic converter 18, a first power module 19, a second power module 20, a DC redundancy module 21, and a DC UPS module 22. The 220V AC main power supply circuit 16 is connected to the first input terminal of the dual-power automatic converter 18, and the 220V DC backup circuit 17 is connected to the second input terminal of the dual-power automatic converter 18. The first power module 19 and the second power module 20 are connected in parallel to the output circuit of the dual-power automatic converter 18. The positive output terminals of the first power module 19 and the second power module 20 are connected to the DC redundancy module 21, and the positive output terminal of the DC redundancy module 21 is connected to the positive input terminal of the DC UPS module 22. The negative output terminals of the first power module 19, the second power module 20, and the DC redundancy module 21 are all connected to the negative input terminal of the DC UPS module 22. The UPS output is connected to the PLC control module and each solenoid valve in the solenoid valve group; the solenoid valve group is controlled by the PLC control module, which controls the on / off state of each solenoid valve in the solenoid valve group.

[0061] In the aforementioned solenoid valve control circuit 3, the function of the dual-power automatic converter 18 is to automatically switch to the backup circuit 17 when the 220V AC main power supply circuit 16 fails, ensuring the reliability and continuity of power supply. The first power module 19 and the second power module 20 serve as backups for each other, both powered by the DC redundant module 21, preventing the DC redundant module 21 from having no input power in case of a fault. The DC redundant module 21 provides electrical isolation and decoupling for the first power module 19 and the second power module 20, preventing a fault in one path from propagating to the other, ensuring that the two power supplies do not interfere with each other, eliminating the effects of circulating current, ensuring that the system will not shut down when one path loses power, and also has the functions of current sharing, load balancing, and ensuring voltage stability; at the same time, the DC redundant module 21 converts 220V AC to 24V DC output to power the DC UPS module 22.

[0062] This embodiment constructs a highly reliable system across the entire "power supply-execution-control" chain by implementing dual-circuit redundancy of the main power supply, backup switching of the oil pump motor main circuit, and multi-layer power supply protection for the solenoid valve control circuit. This effectively solves the problems of single power supply, insufficient protection, and weak fault resistance in traditional braking circuits, providing a solid circuit foundation for the safe shutdown of hydro-generator units.

[0063] Example 2

[0064] As another preferred embodiment of the present invention, this embodiment further supplements and elaborates on the technical solution of the present invention based on the above-described embodiment 1. In this embodiment, the linkage mechanism between the brake hydraulic system and the control circuit is further refined, and the selection characteristics of the solenoid valve group, the pipeline connection logic, and the collaborative control process of the PLC and LCU are clarified, as detailed in the appendix to the specification. Figure 7 As shown, the specific technical solution is as follows:

[0065] The solenoid valve group of the brake hydraulic system is installed on the oil supply line 25 and the oil return line 26 between the oil tank 23 and the brake 24. The solenoid valve group includes an upper solenoid valve 27 and a lower solenoid valve 28.

[0066] Upper gate solenoid valve 27: Installed on the main oil supply line from oil tank 23 to brake 24, it adopts a single coil normally closed direct-acting solenoid valve (such as model ZCT-15, nominal diameter 15mm). Its core characteristic is "power on and power off, full reset": Under normal conditions, the valve core is kept closed by the spring force, blocking the flow of hydraulic oil to brake 24; when receiving a PLC control signal (DC24V), the electromagnetic force overcomes the spring force to push the valve core open, and high-pressure hydraulic oil (pressure established by oil pump motor) enters brake 24 through oil supply line 25, driving the upper and lower brake discs to fit against the brake disc, realizing the braking action.

[0067] Brake release solenoid valve 28: Installed on the main return oil line from brake 24 to oil tank 23, it adopts a single coil normally open direct-acting solenoid valve (such as model ZCT-20, nominal diameter 20mm). Its core characteristic is "power off, power on, full reset": Under normal conditions, the valve core remains open to ensure that the hydraulic oil in brake 24 can flow back to oil tank 23 through return oil line 26; when receiving PLC control signal, the valve core closes the return oil passage to maintain the pressure stability in brake 24.

[0068] Both types of solenoid valves feature a zero-leakage design: the valve seat and valve core are precision ground, and the valve stem interface is equipped with double O-ring seals to ensure that hydraulic oil leakage is ≤0.1mL / min when closed, avoiding both oil waste and abnormal brake pressure decay. Simultaneously, the solenoid valve response time is ≤50ms, enabling rapid execution of PLC commands and reducing braking action delay.

[0069] The first oil pump motor 11 and the second oil pump motor 15 serve as hydraulic power sources, forming a closed-loop control with the solenoid valve group. The input ends of both oil pump motors are connected to the oil tank 23 through an oil suction filter, and the output ends are connected to the main oil supply line after being merged through high-pressure oil pipes, and connected to the inlet end of the upper gate solenoid valve 27. Under normal working conditions, the PLC selects one of the motors to operate according to preset logic (e.g., the first oil pump motor 11 is the main motor and the second oil pump motor 15 is the backup motor), and starts the motor by driving the corresponding contactor (the first contactor 9 or the second contactor 13), pressurizing the hydraulic oil in the oil tank 23 and delivering it to the oil supply line 25. When the oil pump motor is running, the pressure of the oil supply line 25 is monitored in real time by a pressure sensor, and the signal is fed back to the PLC to ensure that the system pressure is stable within the braking range.

[0070] The PLC control module and the LCU monitoring system of the braking system establish real-time communication via industrial Ethernet (communication protocol Modbus TCP / IP), forming a hierarchical control logic of "upper-level decision-making - lower-level execution". The specific process is as follows:

[0071] 1. Braking command trigger: The LCU monitoring system monitors the unit status in real time (such as GCB trip signal, guide vane closing signal, speed signal, etc.). When it determines that the braking activation conditions are met (such as speed ≤ 5% or 20% of rated speed, depending on whether the unit uses electric braking), it sends a "brake activation" command (switch signal or communication message) to the PLC.

[0072] 2. PLC execution logic:

[0073] —Power supply and circuit verification: The PLC first confirms that the main power supply circuit 1 is normal (the dual power automatic transfer switch 4 has no switching abnormality), and the circuit breaker (first circuit breaker 8) and thermal relay (first thermal relay 10) of the selected oil pump motor main circuit (such as the first oil pump motor main circuit 6) are in normal condition (no tripping or overload signal).

[0074] —Drive the oil pump motor: The PLC outputs a control signal to close the first contactor 9, start the first oil pump motor 11 to run, and establish the oil supply pressure;

[0075] —Control the operation of the solenoid valve: After the pressure sensor on the oil supply line 25 detects that the oil supply pressure has reached the set value (e.g., ≥110 bar), the PLC simultaneously outputs an energizing signal to the "up gate solenoid valve 27" (to open the oil supply) and an energizing signal to the "release gate solenoid valve 28" (to close the return oil). The pressure inside the brake 24 rises rapidly, pushing the gate plate to close.

[0076] —Status feedback: The PLC sends a "brake engaged successfully" signal (including pressure value, solenoid valve status, etc.) back to the LCU, which then displays the real-time braking status on the monitoring interface.

[0077] If the PLC detects an abnormality during execution (such as the pressure not reaching the target within 30 seconds after the oil pump motor starts, or the solenoid valve jamming causing an abnormal passage), the following actions will be triggered immediately:

[0078] Automatically switch to the backup oil pump motor (such as the second oil pump motor main circuit 7) and repeat the braking process;

[0079] If the backup circuit is still abnormal, a "brake failure" alarm signal is sent to the LCU, and the brake release solenoid valve 28 is de-energized (opens the return oil) and the oil pump motor is stopped to prevent the system from operating with a fault.

[0080] In this embodiment, the "one-in-use, one-out-of-service" design of the oil pump motor ensures that if a single motor fails, the backup motor can be switched on within 5 seconds to ensure uninterrupted hydraulic power. The solenoid valve adopts a direct-acting structure, eliminating the need for a pilot valve and reducing the risk of intermediate link failures. Its "power-off reset" feature can automatically restore to a safe state (upper gate valve closed, lower gate valve open) when the control power is interrupted, avoiding gate malfunction. The communication link between the PLC and LCU uses fiber optic backup, combined with hard-wired switch signal verification, to prevent instruction loss due to communication interruption.

[0081] This embodiment deeply integrates electrical control and hydraulic execution by clarifying the selection characteristics of the solenoid valve, refining the linkage logic of "motor-solenoid valve-brake 24" and the collaborative process of PLC and LCU. This ensures the accuracy of braking action (response time ≤200ms) and improves the system's fault resistance through multi-layer redundancy design, realizing the "controllable, measurable and reliable" braking process of the hydro-generator unit.

[0082] Example 3

[0083] As another preferred embodiment of the present invention, this embodiment is a further detailed supplement and explanation of the technical solution of the present invention based on the above-described embodiment 2. (Refer to the appendix of the specification.) Figure 7 As shown, an accumulator 29 and a matching pressure relief device are introduced into the brake hydraulic system. The braking response speed and fault resistance are improved through a "pre-pressure build-up + emergency redundancy" design. The specific technical solution is as follows:

[0084] An accumulator 29 is connected in parallel to the oil supply line 25. Its inlet is connected to the oil supply line 25 of the first oil pump motor 11 and the second oil pump motor 15, and its outlet is connected to the oil supply line 25 at the front end of the upper gate solenoid valve 27. The accumulator 29 can pre-store pressurized oil. After selecting near-ground or remote braking control, the system first executes the "ready function", that is, the accumulator 29 is pressurized. According to the motor selection, the first contactor 9 or the second contactor 13 is closed to start the corresponding oil pump motor (first oil pump motor 11 or second oil pump motor 15), and the pressure relief solenoid valve 31 is energized and closed. According to the preset charging pressure on the PLC, the pressure sensor on the accumulator 29 detects the charging value, and the charging stops after the preset pressure is reached.

[0085] As an example, when the PLC control module receives a braking command, it closes the first contactor 9 or the second contactor 13 according to the motor selection, starting the corresponding oil pump motor (first oil pump motor 11 or second oil pump motor 15). Simultaneously, the PLC outputs an energized signal to the "closing solenoid valve 27" (to open the oil supply) and an energized signal to the "releasing solenoid valve 28" (to close the return oil). The pressure inside the brake 24 rises rapidly, pushing the brake plate to close. At this time, because there is hydraulic oil at a set pressure in the accumulator 29, an immediate braking response can be achieved.

[0086] As another example, when the PLC control module receives a braking command, it outputs an energized signal to the "braking solenoid valve 27" (to open the oil supply) and an energized signal to the "releasing solenoid valve 28" (to close the return oil). The pressure inside the brake 24 rises rapidly, pushing the brake plate to close. Braking is achieved using the pressure in the accumulator 29. Upon receiving a release command from near or far, the PLC controls the braking solenoid valve 27 to close (cut off the oil supply) and the releasing solenoid valve 28 to open (enable the return oil). The hydraulic oil in the brake 24 flows back to the oil tank 23 through the return oil line 26. When the pressure sensor on the oil supply line 25 at the rear end of the braking solenoid valve 27 detects that the pressure has dropped to 0 bar, the release is determined to be complete. After the release, the PLC controls the oil pump motor to start, re-pressurizing the accumulator 29 to a ready state, waiting for the next braking command.

[0087] As another example, the PLC simultaneously starts the oil pump motor (such as the first oil pump motor 11) and opens the upper solenoid valve 27 and closes the lower solenoid valve 28; the oil pump motor provides continuous pressure, and the accumulator 29 supplements the instantaneous flow, together supplying oil to the brake 24 to ensure that the pressure rises quickly to the set value.

[0088] As another example, if the first oil pump motor 11 fails to start or trips during operation, the PLC immediately closes the upper solenoid valve 27 and triggers an alarm. At the same time, it relies solely on the accumulator 29 to release the pre-stored pressure oil and supplies oil to the brake 24 through the upper solenoid valve 27 (the pressure of the accumulator 29 can maintain the pressure requirement for a single braking action) to complete the braking action.

[0089] When the oil pump motor starts or stops or the load changes, the accumulator 29 absorbs pressure shocks, keeping the pressure fluctuations in the oil supply line 25 within a reasonable range. When both oil pump motors fail, the braking action is completed independently using the pressurized oil stored in the accumulator 29.

[0090] The accumulator 29 is connected to an independent pressure relief pipeline 30 at its bottom. A pressure relief solenoid valve 31 is installed on the pipeline, and its outlet is connected to the return oil pipeline 26. It adopts a single-coil normally closed direct-acting solenoid valve (10mm diameter) with the characteristic of "closing when energized and fully resetting when de-energized" - under normal conditions (de-energized), the valve opens and the pressure of the accumulator 29 can be released through the pressure relief pipeline 30; when energized, the valve closes, blocking the pressure relief passage and ensuring that the accumulator 29 stores pressure normally.

[0091] The pressure relief solenoid valve 31 is controlled by the PLC and is kept energized. Only when the accumulator 29 is under maintenance, the braking system is under maintenance, or all external power supplies (AC380V, AC220V, and DC220V) are disconnected for 30 minutes, will the PLC de-energize the pressure relief solenoid valve 31, and the branch of the accumulator 29 will release current and pressure. When all external power supplies are disconnected, the PLC will send a power failure alarm signal to the LCU. If the external power supply has not been restored after 30 minutes, the PLC will directly cut off the UPS, including disconnecting the battery inside the UPS, which is equivalent to shutting down the machine directly.

[0092] Because the accumulator 29 pre-stores high-pressure oil, there is no need to wait for the oil pump motor to build up pressure after the braking command is triggered. The time for the brake 24 pressure to rise from 0 to the braking pressure is greatly shortened, reducing the unit's high-speed idling time. When both oil pump motors fail (such as circuit breaker tripping or motor burnout), the accumulator 29 can independently provide the pressure oil required for one braking operation, avoiding braking failure due to power source failure, which is especially suitable for emergency shutdown scenarios. After the preparation stage pressurization is completed, the oil pump motor does not need to run continuously, only replenishing pressure when the pressure is below the threshold, reducing the motor's no-load energy consumption. Enhanced pressure stability: The buffering effect of the accumulator 29 reduces the pressure fluctuation amplitude of the oil supply line 25, reducing fatigue damage to solenoid valves and pipe joints, and extending the life of hydraulic components.

[0093] This embodiment, through the introduction of accumulator 29 and pressure relief system, constructs a dual-mode power guarantee system of "active pre-pressure building up + passive emergency use", which not only improves the timeliness and stability of braking action, but also further strengthens the risk resistance capability of the hydro-generator unit braking system through redundancy design under fault conditions, thus achieving the dual goals of "efficient braking" and "safety redundancy".

[0094] Example 4

[0095] As another preferred embodiment of the present invention, this embodiment further supplements and elaborates on the technical solution of the present invention based on the above-described embodiments 1, 2, or 3. The power protection, status monitoring, and emergency power supply system for the solenoid valve control circuit are designed in detail, and the circuit reliability is improved through a multi-level protection mechanism. Refer to the appendix of the specification. Figure 4 Appendix Figure 5 and attached Figure 6 As shown, the specific technical solution is as follows:

[0096] A third circuit breaker 32 is installed on the 220V AC main power supply circuit 16, and a fourth circuit breaker 33 and a DC / AC inverter 34 are connected in series on the backup circuit 17. The third circuit breaker 32 is connected in series at the front end of the 220V AC main power supply circuit 16 and is a miniature circuit breaker with a rated current of 10A (breaking capacity ≥6kA), normally in a manually closed state. When debugging or maintaining downstream components (such as the dual-power automatic converter 18, power module), the third circuit breaker 32 can be manually disconnected to cut off the 220VAC input, ensuring complete power loss to the downstream circuit and meeting the "no-live operation" requirement in electrical safety regulations. When a short circuit occurs in the downstream circuit (such as power module breakdown) or a sustained overload (current >10A), the third circuit breaker 32 can automatically trip within 0.1 seconds, cutting off the faulty circuit and preventing the spread of fire or arc to the plant's AC power grid.

[0097] The 220V DC backup power supply circuit is connected in series with the fourth circuit breaker 33 and the DC / AC inverter 34. The fourth circuit breaker 33 has the same specifications as the third circuit breaker 32 (rated current 10A), and is normally in the manually closed state. It can be used as an isolation point for the 220VDC power supply. When it is disconnected during maintenance, it can ensure that the inverter and subsequent circuits are de-energized. When the inverter has an internal short circuit or abnormal output, the fourth circuit breaker 33 will automatically trip to prevent the plant's DC power supply panel from being damaged by overcurrent.

[0098] In a preferred embodiment, a power monitoring module 35 is connected in parallel in the connection circuit between the first power module 19, the second power module 20, the redundant module, and the DCUPS module 22. The power monitoring module 35 is connected to a PLC control module. The PLC control module determines the fault signal of the DC UPS module 22 collected by the power monitoring module 35. If a fault is determined in the DC UPS module 22, the PLC control module sends the fault signal to the LCU monitoring system. The power monitoring module 35 monitors the DC UPS module 22 to ensure the reliability of its power supply. When the DC redundant module 21 fails, a power fault alarm will occur. The power fault alarm signal is sent to the LCU monitoring system of the braking system via the PLC control module, providing a signal indicating whether braking is appropriate.

[0099] As a preferred embodiment, the DC UPS module 22 is connected to a power supply battery 36. When both the 220V AC power supply circuit and the 220V DC power supply circuit in the solenoid valve control circuit 3 are de-energized, the power supply battery 36 supplies power to the solenoid valve.

[0100] This embodiment constructs a full life-cycle power supply guarantee system for the solenoid valve control circuit through a three-level design of "input protection - status monitoring - emergency power supply". It not only meets the maintenance safety specifications, but also can quickly respond and ensure the braking function in the event of power failure, further improving the system's risk resistance capability.

[0101] Example 5

[0102] As another preferred embodiment of the present invention, this embodiment is a further detailed supplement and explanation of the technical solution of the present invention based on the above-described embodiments 1, 2, 3, or 4. (Refer to the appendix of the specification.) Figure 1 and attached Figure 8 As shown, a fuel tank heater circuit 37 is also connected in parallel to the main power supply circuit 1. The fuel tank heater circuit 37 includes a fifth circuit breaker 38, an NC regulating switch 39, and a heater 40. The fifth circuit breaker 38 is used to control the on / off state of the fuel tank heater circuit 37, and the NC regulating switch 39 and the heater 40 are connected in series in the fuel tank heater circuit 37. A temperature sensing resistor is provided on the heater 40.

[0103] The oil tank heater circuit 37 prevents the oil temperature in the oil tank 23 from becoming too low or too high. The oil temperature is measured by a temperature-sensing resistor integrated on the heater 40. It automatically heats the oil when the temperature is too low and automatically disconnects the NC regulating switch when the oil temperature returns to normal. The NC regulating switch 39 is normally open, and the fifth circuit breaker 38 is normally closed. The fifth circuit breaker 38 serves as an electrical isolation power supply for the heater 40 and NC regulating switch 39 during maintenance. A separate oil temperature and level fault monitoring sensor is installed inside the oil tank 23. Upon detecting a fault, the fault signal is output to the LCU monitoring system via the PLC control module.

Claims

1. A braking control circuit structure for a hydroelectric generating unit, characterized by: The application relates to a total power supply circuit (1), an oil pump motor main circuit (2), an electromagnetic valve control circuit (3) and a PLC control module. The total power supply circuit (1) is powered by two power supply circuits with different sources, the two power supply circuits with different sources are connected to the total power supply circuit (1) through a double power automatic switching switch (4), and a main circuit breaker (5) for controlling the on-off of the total power supply circuit (1) is arranged on the total power supply circuit (1); The oil pump motor main circuit (2) comprises a first oil pump motor main circuit (6) and a second oil pump motor main circuit (7) in one-use-one-backup mode; the first oil pump motor main circuit (6) and the second oil pump motor main circuit (7) are connected in parallel on the total power supply circuit (1) and are powered by the total power supply circuit (1); the first oil pump motor main circuit (6) is sequentially connected in series with a first circuit breaker (8), a first contactor (9), a first thermal relay (10) and a first oil pump motor (11); the second oil pump motor main circuit (7) is sequentially connected in series with a second circuit breaker (12), a second contactor (13), a second thermal relay (14) and a second oil pump motor (15); the first contactor (9) and the second contactor (13) are connected with the PLC control module in control connection and are controlled to be turned on and turned off by the PLC control module; the normally open contact of the first thermal relay (10) and the second thermal relay (14) is connected with the PLC control module, the normally open contact is closed after the oil pump motor is overloaded, a signal is transmitted to the PLC control module, and the normally closed contact of the first thermal relay (10) and the second thermal relay (14) is respectively connected in series in the first oil pump motor main circuit (6) and the second oil pump motor main circuit (7). The electromagnetic valve control circuit (3) is used for supplying power for the PLC control module and the electromagnetic valve group of the brake hydraulic system, and comprises a 220V AC normal power supply circuit (16), a 220V DC and inverter composed standby circuit (17), a dual power automatic transfer switch (18), a first power module (19), a second power module (20), a DC redundancy module (21) and a DC UPS module (22); the 220V AC normal power supply circuit (16) is connected to the first input end of the dual power automatic transfer switch (18), and the 220V DC standby circuit (17) is connected to the second input end of the dual power automatic transfer switch (18); the first power module (19) and the second power module (20) are connected in parallel to the output circuit of the dual power automatic transfer switch (18); the positive output ends of the first power module (19) and the second power module (20) are connected to the DC redundancy module (21), and the positive output end of the DC redundancy module (21) is connected to the positive input end of the DC UPS module (22); the negative output ends of the first power module (19), the second power module (20) and the DC redundancy module (21) are all connected to the negative input end of the DC UPS module (22); the output end of the DC UPS is connected with the PLC control module and each electromagnetic valve in the electromagnetic valve group; the electromagnetic valve group is connected with the PLC control module for control, and the PLC control module controls the on-off of each electromagnetic valve in the electromagnetic valve group.

2. A braking control circuit structure for a hydroelectric generator set according to claim 1, characterized in that: The electromagnetic valve group of the brake hydraulic system is arranged on the oil supply pipeline (25) and the oil return pipeline (26) between the oil tank (23) and the brake (24), and comprises an upper brake electromagnetic valve (27) and a brake release electromagnetic valve (28); the upper brake electromagnetic valve (27) is arranged on the oil supply pipeline (25), and the brake release electromagnetic valve (28) is arranged on the oil return pipeline (26); the input end of the first oil pump motor (11) is connected with the oil tank (23), and the output end is connected with the oil supply pipeline (25); the input end of the second oil pump motor (15) is connected with the oil tank (23), and the output end of the second oil pump motor (15) is connected with the oil supply pipeline (25); the upper brake electromagnetic valve (27) and the brake release electromagnetic valve (28) are both connected with the PLC control module for control.

3. A braking control circuit structure for a hydroelectric generator set according to claim 2, characterized in that: The PLC control module is in communication connection with the LCU monitoring system of the brake system; after receiving the brake application signal of the LCU monitoring system, the PLC control module controls the first contactor (9) or the second contactor (13) in the first oil pump motor main circuit (6) or the second oil pump motor main circuit (7) to be closed; controls the upper brake electromagnetic valve (27) to be opened, the oil supply pipeline (25) to supply oil to the brake (24), controls the brake release electromagnetic valve (28) to be closed, and the oil return pipeline (26) to be disconnected, so as to brake.

4. A braking control circuit structure for a hydroelectric generator set according to claim 2 or 3, characterized in that: The upper brake electromagnetic valve (27) is a single-coil normally closed electromagnetic valve which is on when powered and resets when powered off; the brake release electromagnetic valve (28) is a single-coil normally open electromagnetic valve which is on when powered off and resets when powered.

5. A braking control circuit structure for a hydroelectric generator set according to claim 2 or 3, characterized in that: An accumulator (29) is further arranged on the oil supply pipeline (25), the accumulator (29) is provided with a pressure relief pipeline (30), the pressure relief pipeline (30) is provided with a pressure relief electromagnetic valve (31), and the pressure relief pipeline (30) is connected to the oil return pipeline (26); the pressure relief electromagnetic valve (31) is in control connection with the PLC control module; the accumulator (29) is further provided with a pressure sensor, and the pressure sensor is in electrical connection with the PLC control module.

6. A braking control circuit arrangement for a hydroelectric generator set as claimed in claim 5, characterized in that: The pressure relief electromagnetic valve (31) is a single-coil normally open electromagnetic valve with power-on closing and power-off full reset.

7. A braking control circuit structure for a hydroelectric generator set according to any one of claims 1 to 3, characterized in that: A third circuit breaker (32) is arranged on the 220V AC power supply circuit (16), and a fourth circuit breaker (33) and a DC / AC inverter (34) are sequentially connected in series on the standby circuit (17).

8. A braking control circuit structure for a hydroelectric generator set according to any one of claims 1 to 3, characterized in that: A power supply monitoring module (35) is connected in parallel in the connection circuit between the first power module (19), the second power module (20) and the redundant module and the DC UPS module (22), the power supply monitoring module (35) is connected with the PLC control module, and the PLC control module judges the fault signal of the DC UPS module (22) collected by the power supply monitoring module (35), and sends the fault signal of the DC UPS module (22) to the LCU monitoring system after judging the fault of the DC UPS module (22).

9. A braking control circuit arrangement for a hydroelectric generator set as claimed in claim 8, characterized in that: The DC UPS module (22) is connected with a power supply battery (36), when the 220V AC power supply circuit and the 220V DC power supply circuit in the electromagnetic valve control circuit (3) are both powered off, the power supply battery (36) supplies power to the DC UPS module (22).

10. A braking control circuit structure for a hydroelectric generating unit according to any one of claims 1 to 3, characterized in that: The total power supply circuit (1) is further connected in parallel with an oil tank heater circuit (37).

11. A braking control circuit arrangement for a hydroelectric generator set as claimed in claim 10, characterized in that: The oil tank heater circuit (37) comprises a fifth circuit breaker (38), an NC adjusting switch (39) and a heater (40), the fifth circuit breaker (38) is used for controlling the on-off of the oil tank heater circuit (37), and the NC adjusting switch (39) and the heater (40) are connected in series in the oil tank heater circuit (37).

12. A braking control circuit arrangement for a hydroelectric generator set as claimed in claim 11, characterized in that: A temperature measuring resistor is arranged on the heater (40).

Images