A control circuit and control method for preventing accidental shutdown of a hydro-generator set

Abstract

A control circuit and control method for preventing accidental shutdown of a hydro-turbine generator set, comprising: a control circuit H1 formed by connecting a DC power supply, a photoelectric isolator G3, an alarm relay K2, and an accident shutdown relay K1; a control circuit H2 formed by connecting a DC power supply, a photoelectric isolator G1, a travel switch GS1, a travel switch GS2, and an accident shutdown relay K1; and a control circuit H3 formed by connecting a DC power supply, a photoelectric isolator G2, a travel switch GS1, a travel switch GS2, and an alarm relay K2. The present invention improves the control circuit in the prior art by adding a travel switch, so that the hydro-turbine generator set system is not affected by a single component failure during operation, and reliable backup protection of the system can be realized, thereby achieving the purpose of improving system reliability and reducing failure rate.

Description

Technical Field

[0001] The invention relates to the technical field of electrical automation control of hydropower plants, and in particular to a control loop and a control method for preventing accidental shutdown of a hydro-generator set. Background Art

[0002] As the last protection system of the hydro-turbine generator set, the mechanical overspeed protection of the hydro-turbine generator set accurately acts according to the process set by the system when the unit overspeeds, closes the guide vanes in time, realizes the unit shutdown, prevents the unit from running away, and ensures the safe operation of the hydro-turbine generator. The mechanical overspeed node of the unit speed governor uses a travel switch node output, which is installed above the mechanical overspeed device and is clamped by the clamping rod of the mechanical overspeed device. A pair of normally closed nodes are used and sent to the monitoring system LCU to participate in the first-class mechanical accident judgment. It belongs to the single-point protection of the unit and has serious equipment hidden dangers. Due to the large vibration of the waterwheel room environment, the mechanical overspeed contact may malfunction due to the loosening of the travel switch fixing bolts, causing the direct-acting contacts to return to the free state, the loosening of the wiring terminals, the jitter of the travel switch contacts, or the failure of the control cable, resulting in the accident shutdown caused by the full closure of the guide vanes and the falling of the fast door. Therefore, starting from the control circuit of the hydraulic turbine backup protection mechanical overspeed contact, by improving the hydraulic turbine backup protection control logic, the purpose of preventing the unit from being shut down due to mechanical overspeed malfunction of the hydraulic turbine generator set is achieved. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a control circuit for preventing the accidental shutdown of a hydro-turbine generator set, and improves the control circuit in the prior art by adding a travel switch, so that the hydro-turbine generator set system is not affected by the failure of a single component during operation, and reliable backup protection of the system can be achieved, thereby achieving the purpose of improving system reliability and reducing failure rate. The economic losses caused by shutdown or equipment damage caused by single component failure or contact failure can be effectively avoided.

[0004] The technical solution adopted by the present invention is:

[0005] A control circuit for preventing accidental shutdown of a hydro-generator set, comprising a travel switch GS1, a travel switch GS2, an accidental shutdown relay K1, an alarm relay K2, and a time delay relay KT;

[0006] One end of the DC power supply is connected to one side of the photoelectric isolation board G3, the other side of the photoelectric isolation board G3 is connected to one end of the normally open contact of the alarm relay K2, the other end of the normally open contact of the alarm relay K2 is connected to one end of the normally closed contact of the accident shutdown relay K1, the other end of the normally closed contact of the accident shutdown relay K1 is connected to one end of the delay relay KT, and the other end of the delay relay KT is connected to the other end of the DC power supply, forming a control loop H1;

[0007] One end of the DC power supply is connected to one side of the photoelectric isolator G1, the other side of the photoelectric isolator G1 is connected to one end of the travel switch GS1, the other end of the travel switch GS1 is connected to one end of the travel switch GS2, the other end of the travel switch GS2 is connected to one end of the coil of the emergency stop relay K1, and the other end of the coil of the emergency stop relay K1 is respectively connected to the other end of the DC power supply, forming a control loop H2;

[0008] One end of the DC power supply is connected to one side of the photoelectric isolation board G2, and the other side of the photoelectric isolation board G2 is respectively connected to one end of the travel switch GS1 and one end of the travel switch GS2. The other ends of the travel switch GS1 and the other ends of the travel switch GS2 are connected to one end of the alarm relay K2 coil, and the other end of the alarm relay K2 coil is connected to the other end of the DC power supply, forming a control circuit H3.

[0009] The photoelectric isolator board G1, the photoelectric isolator board G2 and the photoelectric isolator board G3 preferably adopt the B-TD 00107A photoelectric isolator board developed by NSD.

[0010] The travel switch GS2 is connected to the local control cabinet of the unit LCU through an independent control cable to transmit the mechanical overspeed signal.

[0011] The travel switch GS1 and the travel switch GS2 have at least two node outputs, a small mechanical travel dead zone, reliable operation, and improved system performance.

[0012] As the travel switch GS1 and the travel switch GS2, Omron HL 5100 travel switch is preferred.

[0013] The accident shutdown relay K1 and the alarm relay K2 preferably use gold-plated nodes to prevent them from corroding and rusting, which may cause the nodes to become insensitive.

[0014] The time delay relay KT preferably adopts a controller with high delay accuracy, wide delay range, small and compact size, and uses gold-plated contacts.

[0015] The DC power supply is a 24VDC power supply.

[0016] A control method for preventing accidental shutdown of a hydro-generator set,

[0017] The mechanical overspeed node signal adopts the normally closed node output of the travel switch GS1 and the travel switch GS2, and uses two independent cables to send the signal respectively. The judgment logic of the mechanical overspeed signal adopts negative logic;

[0018] In the control loop H3, the travel switch GS2 is connected in parallel with the original travel switch GS1 to realize the single-point fault alarm function of mechanical overspeed, and effectively prevent the phenomenon that the unit mechanical overspeed operates normally but its signal refuses to operate;

[0019] In the control loop H2, the travel switch GS2 is connected in series with the original travel switch GS1 to realize the mechanical overspeed signal action and perform an emergency shutdown, and effectively prevent the mechanical overspeed signal from malfunctioning.

[0020] The present invention provides a control circuit to prevent accidental shutdown of a hydro-generator set, and the technical effects are as follows:

[0021] 1: The present invention adds a mechanical overspeed signal to the mechanical overspeed signal control loop of the mechanical overspeed device, and uses two independent cables to send the signals respectively. The judgment logic of the mechanical overspeed signal adopts negative logic. The newly added travel switch GS2 is connected in parallel with the original travel switch GS1 to realize the mechanical overspeed single-point fault alarm function and effectively prevent the phenomenon that the unit's mechanical overspeed operates normally but its signal refuses to operate.

[0022] The newly added travel switch GS2 is connected in series with the original travel switch GS1 to realize the mechanical overspeed signal action and perform emergency shutdown, and effectively prevent the mechanical overspeed signal from malfunctioning, thereby achieving the purpose of improving system reliability and reducing failure rate. It will greatly improve the reliability of the system and effectively avoid economic losses caused by unit shutdown or equipment damage due to single component failure, such as travel switch failure, or signal refusal to operate, signal malfunction, including loose bolts, loose contacts, loose wiring and travel switch failure, thereby ensuring the safe and stable operation of the hydropower generating unit.

[0023] 2: The signal control loop of the present invention has simple design, high reliability, low transformation cost and great field application value.

[0024] 3: The additional equipment of the present invention includes a travel switch, two intermediate relays, a time delay relay and a control cable, and has the characteristics of advanced design concept, high system reliability and low investment cost.

[0025] 4: After the control logic of the mechanical overspeed signal is optimized, the present invention effectively prevents the phenomenon that the unit mechanical overspeed operates normally but its signal refuses to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The invention relates to a control circuit of a mechanical overspeed signal of a water machine backup protection in the prior art.

[0027] Figure 2 This is the control loop of the mechanical overspeed signal of the water machine backup protection in the present invention.

[0028] Figure 3 Schematic diagram of the installation method of the newly added travel switch GS2 of the present invention and the original travel switch GS1 Figure 1 ;

[0029] Figure 4Schematic diagram of the installation method of the newly added travel switch GS2 of the present invention and the original travel switch GS1 Figure 2 ;

[0030] Among them: a-holding rod, b-turbine main shaft, c-flying swing rod. DETAILED DESCRIPTION

[0031] A control circuit to prevent accidental shutdown of a hydro-turbine generator set. In the control circuit for judging the mechanical overspeed signal of the unit for the hydraulic turbine backup protection, an independent travel switch GS2 is added, and an independent control cable is used to connect the unit LCU local control cabinet to send the mechanical overspeed signal. Due to the structure of the mechanical overspeed device, the judgment logic of the mechanical overspeed signal adopts negative logic, and the newly added travel switch GS2 is connected in series with the original travel switch GS1.

[0032] In the present invention, an independent mechanical overspeed normally closed contact is added, and the original mechanical overspeed contact is added, and the signal is connected to the local control cabinet of the unit LCU through independent cables, so that the signal input circuit can send two mechanical overspeed signals, and the two mechanical overspeed signals are used to perform or logically optimize the single-point fault alarm function of the water machine backup protection mechanical overspeed signal to avoid the signal refusal to act. The control logic judgment of the water machine backup protection mechanical overspeed accident shutdown is improved by performing and logically optimizing the two mechanical overspeed signals, so that the monitoring system can improve the judgment of the mechanical overspeed signal. The mechanical overspeed shutdown circuit effectively avoids the triggering of the monitoring system water machine backup protection information due to the false operation of the mechanical overspeed signal during the operation of the unit by locking the unit speed greater than 115%. The accident shutdown solenoid valve and the mechanical overspeed oil circuit are activated to cause the unit accident shutdown load shedding phenomenon.

[0033] The mechanical overspeed node provided by the present invention adopts the normally closed node output of two travel switches, and the installation method is as follows Figure 3 The travel switch GS1 and the travel switch GS2 are installed above the mechanical overspeed device, the travel switch GS1 and the travel switch GS2 are installed on the upper and lower parts and fixed with bolts, and the travel switch contacts are pressed by the mechanical overspeed device actuating pressing rod a.

[0034] A control method for preventing accidental shutdown of a hydro-generator set,

[0035] The mechanical overspeed node signal adopts the normally closed node output of the travel switch GS1 and the travel switch GS2, and uses two independent cables to send the signal respectively. The judgment logic of the mechanical overspeed signal adopts negative logic;

[0036] In the control loop H3, the travel switch GS2 is connected in parallel with the original travel switch GS1 to realize the single-point fault alarm function of mechanical overspeed, and effectively prevent the phenomenon that the unit mechanical overspeed operates normally but its signal refuses to operate;

[0037] In the control loop H2, the travel switch GS2 is connected in series with the original travel switch GS1 to realize the mechanical overspeed signal action and perform an emergency shutdown, and effectively prevent the mechanical overspeed signal from malfunctioning.

[0038] Example:

[0039] like Figure 2 As shown, a control circuit to prevent the mechanical overspeed signal of a hydro-turbine generator set from malfunctioning and causing an accidental shutdown is shown, wherein an independent travel switch GS2 is added to the control circuit of the hydraulic machine backup protection circuit to judge the mechanical overspeed signal, and an independent control cable is used to connect it to the local control cabinet of the unit LCU to send the mechanical overspeed signal. The judgment logic of the mechanical overspeed signal in the hydraulic machine backup protection adopts negative logic. In the control circuit H2, the normally closed node of the newly added travel switch GS2 is connected in series with the normally closed node of the original travel switch GS1, and the accident shutdown process is directly triggered after passing through the accident shutdown relay K1. In the control circuit H1 and the control circuit H2, the unit speed is greater than 115% signal is locked to prevent the mechanical overspeed signal from malfunctioning.

[0040] In the control loop H3, the judgment logic of the mechanical overspeed signal in the water machine backup protection adopts the normally closed node of the travel switch GS2 in parallel with the normally closed node of the original travel switch GS1, and realizes the monitoring system's alarm function for mechanical overspeed single-point fault through the alarm relay K2.

[0041] In the control loop H1, the normally open contact of the mechanical overspeed single-point fault alarm relay K2 is locked with the normally closed node of the accident shutdown relay K1, and the delay relay KT is used to delay the triggering of the accident shutdown process, so as to avoid erroneous triggering of the accident shutdown process due to malfunction of the relay, so as to facilitate on-site staff to promptly confirm whether the on-site equipment is operating normally and perform emergency processing; at the same time, it can effectively prevent the phenomenon that the unit's mechanical overspeed operates normally but its signal refuses to operate. Among them, in the control loop H1, when the normally closed node of the accident shutdown relay K1K1 is locked, in order to avoid repeated issuance of commands when the two mechanical overspeed signals GS1 and GS2 operate at the same time, avoid repeated initiation of the accident shutdown process.

[0042] According to the mechanical overspeed signal logic adopted by the water machine backup protection, the above embodiment takes two mechanical overspeed signals for logical optimization and improves the water machine backup protection signal judgment logic: for the speed regulator mechanical overspeed signal adopting negative logic, the newly added travel switch GS2 is connected in parallel with the original travel switch GS1 to realize the mechanical overspeed single-point fault alarm function, and effectively prevent the phenomenon that the unit mechanical overspeed operates normally but its signal refuses to operate. The two closed contacts are combined in series to trigger the accident shutdown process, and the two closed contacts are connected in parallel to send single-point fault alarm signals, thereby effectively preventing the mechanical overspeed accident shutdown caused by single component failure, single mechanical overspeed signal contact malfunction, loose wiring, etc.

Claims

1. A control circuit for preventing accidental shutdown of a hydro-generator set, comprising a travel switch GS1, a travel switch GS2, an accidental shutdown relay K1, an alarm relay K2, and a delay relay KT; characterized in that: One end of the DC power supply is connected to one side of the photoelectric isolation board G3, the other side of the photoelectric isolation board G3 is connected to one end of the normally open contact of the alarm relay K2, the other end of the normally open contact of the alarm relay K2 is connected to one end of the normally closed contact of the accident shutdown relay K1, the other end of the normally closed contact of the accident shutdown relay K1 is connected to one end of the delay relay KT, and the other end of the delay relay KT is connected to the other end of the DC power supply, forming a control loop H1; One end of the DC power supply is connected to one side of the photoelectric isolator G1, the other side of the photoelectric isolator G1 is connected to one end of the travel switch GS1, the other end of the travel switch GS1 is connected to one end of the travel switch GS2, the other end of the travel switch GS2 is connected to one end of the coil of the emergency stop relay K1, and the other end of the coil of the emergency stop relay K1 is respectively connected to the other end of the DC power supply, forming a control loop H2; One end of the DC power supply is connected to one side of the photoelectric isolator G2, and the other side of the photoelectric isolator G2 is respectively connected to one end of the travel switch GS1 and one end of the travel switch GS2, and the other end of the travel switch GS1 and the other end of the travel switch GS2 are connected to one end of the alarm relay K2 coil, and the other end of the alarm relay K2 coil is connected to the other end of the DC power supply, forming a control loop H3; The travel switch GS2 is connected to the local control cabinet of the unit LCU through an independent control cable to transmit the mechanical overspeed signal; The travel switch GS1 and the travel switch GS2 are installed above the mechanical overspeed device. The travel switch GS1 and the travel switch GS2 are installed on the upper and lower parts and fixed with bolts. The travel switch contacts are pressed by the mechanical overspeed device actuating the pressing rod (a).

2. A control circuit for preventing accidental shutdown of a hydro-generator set according to claim 1, characterized in that: The travel switch GS1 and the travel switch GS2 have at least two node outputs.

3. A control circuit for preventing accidental shutdown of a hydro-generator set according to claim 1, characterized in that: The DC power supply is a 24VDC power supply.

4. A control method for preventing accidental shutdown of a hydro-generator set based on the control loop of claim 1, characterized in that: The mechanical overspeed node signal adopts the normally closed node output of the travel switch GS1 and the travel switch GS2, and uses two independent cables to send the signal respectively. The judgment logic of the mechanical overspeed signal adopts negative logic; In the control loop H3, the travel switch GS2 is connected in parallel with the original travel switch GS1 to realize the single-point fault alarm function of mechanical overspeed, and effectively prevent the phenomenon that the unit mechanical overspeed operates normally but its signal refuses to operate; In the control loop H2, the travel switch GS2 is connected in series with the original travel switch GS1 to realize the mechanical overspeed signal action and perform an emergency shutdown, and effectively prevent the mechanical overspeed signal from malfunctioning.

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