A generator set boiler power interlocking system

Abstract

The application discloses a kind of machine furnace electric joint trip systems of generator unit, belong to the field of generator unit, including steam turbine ETS, generator protection screen thermal protection signal unit, generator protection screen reverse power signal unit and steam turbine main valve closing signal unit, the input end of steam turbine ETS with generator protection screen thermal protection signal unit is communicated connection, and the output end of generator protection screen thermal protection signal unit is connected with engine outlet circuit breaker by thermal protection pressure plate;Generator protection screen reverse power signal is connected with engine outlet circuit breaker;Steam turbine ETS, steam turbine main valve closing signal unit, generator protection screen reverse power signal unit non-signal and steam turbine main valve fault cut-off device are connected.The application not only can avoid the timing difference caused by main valve action and electrical protection action unit overspeed.Simultaneously to main valve inner leakage and other common and multiple cause major fly accident.

Description

Technical Field

[0001] This invention relates to the field of generator sets, specifically a generator set boiler-generator interconnection tripping system. Background Technology

[0002] In traditional generator sets, the signal generated after the turbine ETS protection is triggered is sent to the generator protection panel C via a non-electrical channel. The generator protection device generates a thermal protection signal through logic operation. When the thermal protection hard switch of the generator protection panel is engaged, a trip signal is directly sent to the generator output circuit breaker. During normal unit shutdown, the thermal protection hard switch is manually disengaged, and the generator output circuit breaker is disconnected through the reverse power trip protection program. This occurs when the main steam valve is fully closed and the generator outputs a trip signal to interlock the generator grid-connected circuit breaker tripping when reverse power occurs. During normal operation, the thermal protection hard switch is engaged. When a turbine fault occurs, the turbine trips the generator output circuit breaker directly through thermal protection at the same time as the ETS is activated. With the turbine's automatic main steam valve operating normally, the turbine ETS activation is hydraulically driven, with an activation time of approximately 1 second. However, the activation time of the generator output circuit breaker tripping through thermal protection is less than 40 ms. Therefore, the generator set faces an overspeed risk after tripping. In the event of internal leakage or jamming of the turbine's automatic main steam valve, the generator will be electrically disconnected under the triggering of the thermal protection signal. If the turbine's automatic main steam valve fails to completely cut off the main steam source, the disconnected generator unit will inevitably run away with the engine.

[0003] Currently, most power plants use the main steam valve travel position signal as the condition for whether the generator can be disconnected. This method ensures that the turbine main steam valve has completed its operation before the generator disconnects, effectively preventing overspeed faults caused by premature generator disconnection before the main steam supply is completely cut off. However, the risk of turbine generator overspeed and runaway cannot be avoided when the unit experiences the following two situations.

[0004] Main steam valve internal leakage

[0005] If the ETS (Electronic Transfer Switch) activates and there is internal leakage in the turbine's main steam valve, even if the main steam valve limit switch is functioning normally, the leaking main steam valve cannot effectively disconnect the main steam source. According to the above logic instructions, even after the generator set is electrically disconnected, the unit still faces the risk of overspeeding and runaway.

[0006] Internal leakage or failure to operate of the air extraction check valve

[0007] After the ETS (Electronic Toll Collection) system activates, the turbine main steam valve completes its operation, and the main steam valve limit switch functions normally. However, if the turbine extraction check valve leaks internally or fails to operate, a large amount of steam enters the turbine through the extraction circuit to perform work. At this point, according to the aforementioned logic instructions, even after the generator set is electrically disconnected, the unit still faces the risk of overspeeding and runaway.

[0008] In summary, using the main steam valve travel position signal as the condition for whether the generator can be disconnected cannot completely eliminate the risk of overspeed and runaway of the unit under main steam valve failure. Therefore, a safer generator set boiler-generator interconnection system is needed to solve the above problems. Summary of the Invention

[0009] To address the aforementioned problems in the prior art, the present invention aims to provide a generator set boiler-generator interconnection tripping system to solve the problems mentioned in the background art.

[0010] To achieve the above objectives, the present invention provides the following technical solution:

[0011] A generator set's boiler-generator interconnection trip system includes a turbine ETS, a generator protection panel thermal protection signal unit, a generator protection panel reverse power signal unit, and a turbine main steam valve closing signal unit. The turbine ETS is communicatively connected to the input terminal of the generator protection panel thermal protection signal unit, and the output terminal of the generator protection panel thermal protection signal unit is connected to one input terminal of a first AND gate through a thermal protection pressure plate.

[0012] The generator protection panel reverse power signal unit includes a first generator protection panel reverse power signal unit, a second generator protection panel reverse power signal unit, and a third generator protection panel reverse power signal unit;

[0013] The reverse power signal unit of the first generator protection panel is connected to the other input terminal of the first AND gate; the output terminal of the first AND gate is connected to the engine outlet circuit breaker through an OR gate.

[0014] The reverse power signal unit of the second generator protection panel is directly connected to the engine output circuit breaker via an OR gate.

[0015] The reverse power signal unit of the third generator protection panel and the main steam valve closing signal unit of the turbine are both connected to the reverse power adjustment module. The reverse power adjustment module is connected to the engine outlet circuit breaker through an OR gate.

[0016] The turbine ETS and the turbine main steam valve closing signal unit are both connected to the input of the second AND gate, and the generator protection panel reverse power signal unit is connected to the input of the second AND gate through a NOT gate;

[0017] The output end of the second AND gate is connected to one end of the quick protection pressure plate, and the other end of the quick protection pressure plate is connected to the turbine main steam valve fault cut-off device.

[0018] The turbine main steam valve fault cut-off device includes a boiler combustion burner cut-off module, a boiler vent valve opening module, a PCV pressure relief valve opening module, and a turbine high and low bypass valve opening module.

[0019] As a further aspect of the present invention: the turbine ETS is connected to the thermal protection signal unit of the generator protection panel through a non-electrical quantity channel.

[0020] As a further aspect of the present invention: the first generator protection screen reverse power signal unit is a passive motor protection screen reverse power signal.

[0021] As a further aspect of the present invention:

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] This invention not only avoids unit overspeed caused by the timing difference between main steam valve operation and electrical protection operation, but also addresses common issues such as internal leakage in the main steam valve that have repeatedly led to major runaway accidents. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of a generator set's boiler-electricity interconnection tripping system disclosed in an embodiment. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," and "linked" should be interpreted broadly; for example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0027] Please see Figure 1 A generator set boiler-generator interconnection trip system includes a turbine ETS, a generator protection panel thermal protection signal unit, a generator protection panel reverse power signal unit, and a turbine main steam valve closing signal unit. The turbine ETS is communicatively connected to the input terminal of the generator protection panel thermal protection signal unit, and the output terminal of the generator protection panel thermal protection signal unit is connected to one input terminal of a first AND gate through a thermal protection pressure plate.

[0028] The generator protection panel reverse power signal unit includes a first generator protection panel reverse power signal unit, a second generator protection panel reverse power signal unit, and a third generator protection panel reverse power signal unit;

[0029] The reverse power signal unit of the first generator protection panel is connected to the other input terminal of the first AND gate; the output terminal of the first AND gate is connected to the engine outlet circuit breaker through an OR gate.

[0030] The reverse power signal unit of the second generator protection panel is directly connected to the engine output circuit breaker via an OR gate.

[0031] The reverse power signal unit of the third generator protection panel and the main steam valve closing signal unit of the turbine are both connected to the reverse power adjustment module. The reverse power adjustment module is connected to the engine outlet circuit breaker through an OR gate.

[0032] The turbine ETS and the turbine main steam valve closing signal unit are both connected to the input of the second AND gate, and the generator protection panel reverse power signal unit is connected to the input of the second AND gate through a NOT gate;

[0033] The output end of the second AND gate is connected to one end of the quick protection pressure plate, and the other end of the quick protection pressure plate is connected to the turbine main steam valve fault cut-off device.

[0034] The turbine main steam valve fault cut-off device includes a boiler combustion burner cut-off module, a boiler vent valve opening module, a PCV pressure relief valve opening module, and a turbine high and low bypass valve opening module.

[0035] The turbine's ETS signal is sent to the protection device of the generator protection panel through a non-electrical quantity channel. The device generates a thermal protection signal through logic operations, and simultaneously connects the passive nodes of the turbine's two main steam valve limit switch position signals in series to the thermal protection circuit. When thermal protection occurs, and the turbine's main steam valves have reached the closed position, a tripping signal is sent to the generator output circuit breaker.

[0036] The turbine's ETS signal is sent to the generator protection panel C through a non-electrical quantity channel. The protection device generates a thermal protection signal through logic operations, and simultaneously adds a passive node for the generator reverse power signal, connected in series to the thermal protection circuit. When the thermal protection operates and the generator experiences reverse power, a tripping signal is sent to the generator output circuit breaker.

[0037] This scheme ensures that the generator is disconnected only after reverse power is generated. This scheme mitigates the potential overspeed risk associated with generator disconnection.

[0038] Similarly, the equipment safety issues arising from turbine main steam valve malfunctions must also be addressed. Under normal circumstances, the ETS (Electronic Power Supply System) activates, automatically closing the turbine interlock main steam valve. If the valve effectively cuts off the main steam supply, the generator will generate reverse power and complete the disconnection process. If the main steam valve activates but fails to effectively cut off the main steam supply, and there is positive active power, the generator does not meet the disconnection conditions. Forcibly disconnecting the generator in this situation will cause the turbine to overspeed and run away. However, failing to quickly disconnect the generator set and reduce its speed will also introduce other safety risks.

[0039] Based on the aforementioned potential problems, an important issue that urgently needs to be addressed before the generator is disconnected is to reduce the flow rate of the main steam entering the turbine through the main steam valve to perform work.

[0040] In cases of internal leakage at the main steam valve, simply reducing the main steam pressure rapidly will significantly improve the situation. Therefore, to address this issue, the following logic is added to the DCS system: when the turbine trips and a main steam valve closing signal is received, if no reverse power signal from the generator is received, the system determines that there is internal leakage at the main steam valve or a fault in the extraction check valve. At this point, the DCS reduces the main steam pressure by shutting off the gas burners from the boiler and simultaneously interlocking the opening of the boiler's electric vent valve and PCV valve for external venting. It further depressurizes the turbine by interlocking the opening of the high and low pressure bypass valves. This rapidly reduces the active power output of the turbine generator to zero, and the unit is disconnected from the grid once the generator load reaches zero.

[0041] This solution not only avoids unit overspeed caused by the timing difference between main steam valve operation and electrical protection operation, but also addresses common issues such as internal leakage in the main steam valve that have repeatedly led to major runaway accidents.

[0042] After process optimization and improvement:

[0043] 1. During normal operation of the unit, the "thermal protection switch" is engaged. After a turbine fault triggers the generator protection panel to issue a thermal protection action signal, preparations for disconnection begin. The unit disconnection occurs when the unit load drops to the point where the generator experiences reverse power (1%, 0 seconds).

[0044] 2. During normal unit operation, the "rapid unloading pressure plate" is activated. When the turbine experiences thermal protection but the unit load has not reached zero (no reverse power is detected), in order to quickly reduce the unit load to zero as soon as possible and ensure the unit can be successfully disconnected from the grid, the following steps are taken: Interlocking and disconnecting the boiler combustion nozzles, opening various boiler vent valves to release pressure, and opening the high and low pressure steam bypass filters to release pressure.

[0045] 3. When the generator set is shut down under normal dispatch instructions, the thermal protection pressure plate should be manually disengaged. After the operator reduces the turbine load until the main steam valve is closed, and the generator experiences reverse power (1%, 1..5s), the unit is disconnected from the grid.

[0046] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered exemplary and not restrictive in all respects. The scope of the invention is defined by the appended claims rather than the foregoing description, and therefore all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0047] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A generator set boiler-generator interconnection tripping system, characterized in that, It includes a steam turbine ETS, a generator protection panel thermal protection signal unit, a generator protection panel reverse power signal unit, and a steam turbine main steam valve closing signal unit. The steam turbine ETS is communicatively connected to the input terminal of the generator protection panel thermal protection signal unit, and the output terminal of the generator protection panel thermal protection signal unit is connected to one input terminal of a first AND gate through a thermal protection pressure plate. The generator protection panel reverse power signal unit includes a first generator protection panel reverse power signal unit, a second generator protection panel reverse power signal unit, and a third generator protection panel reverse power signal unit; The reverse power signal unit of the first generator protection panel is connected to the other input terminal of the first AND gate; the output terminal of the first AND gate is connected to the engine outlet circuit breaker through an OR gate. The reverse power signal unit of the second generator protection panel is directly connected to the engine output circuit breaker via an OR gate. The reverse power signal unit of the third generator protection panel and the main steam valve closing signal unit of the turbine are both connected to the reverse power adjustment module. The reverse power adjustment module is connected to the engine outlet circuit breaker through an OR gate. The turbine ETS and the turbine main steam valve closing signal unit are both connected to the input of the second AND gate, and the generator protection panel reverse power signal unit is connected to the input of the second AND gate through a NOT gate; The output end of the second AND gate is connected to one end of the quick protection pressure plate, and the other end of the quick protection pressure plate is connected to the turbine main steam valve fault cut-off device. The turbine main steam valve fault cut-off device includes a boiler combustion burner cut-off module, a boiler vent valve opening module, a PCV pressure relief valve opening module, and a turbine high and low bypass valve opening module.

2. The generator set boiler-generator interconnection tripping system according to claim 1, characterized in that, The turbine ETS is connected to the thermal protection signal unit of the generator protection panel via a non-electrical quantity channel.

3. The generator set boiler-generator interconnection tripping system according to claim 2, characterized in that, The first generator protection screen reverse power signal unit is a passive motor protection screen reverse power signal.

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