A variable frequency system for the cooling air blower of a gas turbine rotor air cooler

Abstract

The present invention discloses a frequency conversion system for a gas turbine rotor cooling air cooler blower, comprising a frequency conversion cabinet, in which a frequency converter, a power frequency contactor, a frequency conversion isolation contactor, and a control circuit are installed. The blower motor is connected to the frequency converter and the power frequency contactor, respectively, to form a frequency conversion and power frequency circuit. The control circuit includes a frequency conversion and power frequency operation control circuit. The frequency conversion operation and power frequency operation control circuits are switched by a power frequency / frequency conversion control switch. The frequency conversion operation control circuit and the power frequency operation control circuit are each provided with two parallel local control branches and a remote control branch. A remote TCS system obtains the cooling air temperature in the rotor cooling air cooler, adjusts it through a PID regulator, and then adjusts the frequency of the frequency converter. The present invention can realize power frequency and variable frequency operation of the blower motor, and can be operated remotely and locally. The PID regulator of the remote TCS system can realize automatic adjustment of the frequency converter frequency to control the rotor cooling at an appropriate temperature.

Description

Technical Field

[0001] The present invention relates to the technical field of rotor cooling air cooler blowers, and in particular to a frequency conversion system of a gas turbine rotor cooling air cooler blower. Background Art

[0002] To prevent damage to high-temperature components in the turbine's hot channel, Mitsubishi gas turbines use a turbine cooling air system to cool these components. The turbine rotor's cooling air comes from the final compressor exhaust; however, due to its high temperature, it requires cooling. The "air-cooled" rotor cooling air cooler and fuel heater are arranged in a stacked arrangement. A portion of the final compressor exhaust is extracted from the turbine body and enters the outdoor rotor cooling air cooler. The turbine's fuel is supplied in the opposite direction and enters the fuel heater located above the rotor cooling air cooler. Three rotor cooling air cooler blowers located at the bottom of the rotor cooling air cooler pump outdoor air upward, generating heat convection and reducing the temperature of the extracted final compressor exhaust. This air is then reintroduced into the turbine body as rotor cooling air, heating the fuel. This protects the hot channel components while increasing combustion temperature and reducing energy consumption.

[0003] The three rotor cooling air blowers are named A, B, and C from the direction of air inlet. All three existing blowers are fixed-frequency blowers, and their automatic start and stop are controlled by logic. During stable operation of the unit, only blower C will trigger the automatic stop condition under extreme operating conditions. Due to the complex logical relationship between the rotor cooling air temperature and the gas turbine unit load and ambient temperature, neither of the above two parameters can be controlled autonomously. Blower C only triggers the self-start condition during the startup process of the gas turbine unit when the rotor cooling air begins to heat up to a rotor cooling air temperature greater than 210°C, increasing heat convection and reducing the rotor cooling air temperature. When the rotor cooling air temperature is less than 155°C, the self-stop condition is triggered, reducing heat convection to increase the rotor cooling air temperature. The control method is relatively simple and cannot achieve precise control of the rotor cooling air temperature.

[0004] Because the fan control method cannot precisely control the temperature of the rotor cooling air, it can also cause gas turbine operating indicators to exceed standards. For example, similar units in northern China will display a second-stage disc clearance overtemperature alarm under low winter operating conditions (the alarm temperature is >460°C). Based on statistical analysis of the mechanical structure and operating parameters at the gas turbine second-stage disc clearance measurement point, it can be concluded that the second-stage disc clearance overtemperature is caused by excessively low rotor cooling air temperature, which in turn is caused by the rotor cooling air cooler blower control method being insufficient to provide appropriate parameters for various operating conditions.

[0005] As shown in Table 1 and Appendix Figure 4 As shown in the operating parameter graph from 7:00 PM to 12:00 AM, the second-stage disc clearance temperature (2DCT) and rotor cooling air (RCA) temperature show a negative correlation: as the air temperature drops, the rotor cooling air gradually decreases, while the second-stage disc clearance temperature remains high and gradually increases. When the rotor cooling air temperature falls below 170°C, the second-stage disc clearance temperature begins to rise abnormally. When the rotor cooling air temperature falls below 155°C, the C blower auto-stop condition is triggered, heat convection decreases, the rotor cooling air temperature rises, and the second-stage disc clearance temperature returns to normal. The peak second-stage disc clearance temperature on that day exceeded the alarm value of 460°C. Under lower ambient temperature conditions, the second-stage disc clearance temperature would remain at a high temperature that damages the equipment for a long time and would easily exceed the over-temperature alarm value frequently.

[0006] Table 1 Comparison of parameters of air cooling system for combustion engine after blower automatic stop

[0007] time 19:00 19:30 20：00 20:30 21:00 21:30 22:00 22:30 23:00 23:30 24:00 2DCT(℃) 417.6 419.3 421.9 421.8 422.1 424.8 431.7 454.9 403.2 393.1 391.3 RCA(℃) 173.4 172.1 170.9 173 173 167.4 168.2 155 205.3 204.2 203.7

[0008] In summary, there is an urgent need for a gas turbine rotor cooling air cooler blower frequency conversion system. Summary of the Invention

[0009] In view of the deficiencies in the prior art, the present invention provides a frequency conversion system for a gas turbine rotor cooling air cooler blower.

[0010] The present invention discloses a frequency conversion system for a gas turbine rotor cooling air cooler blower, comprising a frequency conversion cabinet, wherein a frequency converter, a power frequency contactor, a frequency conversion isolation contactor and a control circuit are installed in the frequency conversion cabinet;

[0011] The input end of the frequency converter is connected to a 380V three-phase AC power supply through a power supply line switch, the output end of the frequency converter is connected to a blower motor in a rotor cooling air cooler through a normally open contact of a frequency conversion isolation contactor to form a frequency conversion circuit, and the input end of the blower motor is connected to a 380V three-phase AC power supply through a normally open contact of a power frequency contactor and a power supply line switch to form a power frequency circuit, and the power frequency contactor and the frequency conversion isolation contactor are electrically interlocked;

[0012] The control circuit includes a variable frequency operation control circuit and a power frequency operation control circuit, and the variable frequency operation control circuit and the power frequency operation control circuit are switched by a power frequency / variable frequency control switch to enable the blower motor to operate in variable frequency or power frequency;

[0013] The variable frequency operation control circuit and the power frequency operation control circuit are both provided with two parallel local control branches and remote control branches, and the local control branch and the remote control branch are switched by a local / remote control switch;

[0014] The analog input channel of the frequency converter is connected to the analog output channel of the remote TCS system. The remote TCS system obtains the temperature of the rotor cooling air in the rotor cooling air cooler in real time. The PID regulator in the remote TCS system is used to calculate the deviation between the temperature of the rotor cooling air and a set value. The remote TCS system adjusts the frequency of the frequency converter in real time through the PID regulator.

[0015] As a further improvement of the present invention, the power frequency circuit further includes a power frequency thermal relay, which is connected in series between the input end of the blower motor and the normally open contact of the power frequency contactor.

[0016] As a further improvement of the present invention, the frequency converter is an ACS-510 frequency converter, and terminals 2 and 3 of the ACS-510 frequency converter are connected to the analog output channel of the remote TCS system;

[0017] Terminals 22 and 25 of the ACS-510 inverter are short-circuited and connected to the live wire in the cabinet via a single-pole circuit breaker. Terminal 24 of the ACS-510 inverter is connected to one end of the coil of the frequency conversion fault action relay. Terminal 27 of the ACS-510 inverter is connected to one end of the coil of the frequency conversion operation status relay. The other ends of the coils of the frequency conversion fault action relay and the frequency conversion operation status relay are both connected to the neutral wire in the cabinet.

[0018] Both ends of the coil of the frequency conversion fault action relay are connected in parallel with frequency conversion fault indicator lights, and both ends of the coil of the frequency conversion operation status relay are connected in parallel with frequency conversion operation indicator lights.

[0019] As a further improvement of the present invention, the DO1 channel of the remote TCS system is connected to one end of the coil of the remote operation command relay, and the other end of the coil of the remote operation command relay is connected to the live wire in the cabinet through the single-pole circuit breaker.

[0020] As a further improvement of the present invention, the variable frequency operation control circuit includes a variable frequency start button, a variable frequency stop button, and a variable frequency operation relay;

[0021] One end of a group of normally closed contacts of the variable frequency fault action relay is connected to terminal 2 of the power frequency / variable frequency control switch, and the other end is connected to terminal 1 and terminal 3 of the local / remote control switch respectively;

[0022] The outgoing line of terminal 2 of the local / remote control switch is connected in series with the frequency conversion stop button and the frequency conversion start button in sequence;

[0023] The output terminal of terminal 4 of the local / remote control switch is connected in series with the normally open contact of the remote operation command relay. The output terminal of the normally open contact of the remote operation command relay is connected in parallel with the output terminal of the frequency conversion start button and then connected to one end of the coil of the frequency conversion operation relay. The other end of the coil of the frequency conversion operation relay is connected to the neutral line in the cabinet.

[0024] Two ends of a group of normally open contacts of the variable frequency operation relay are connected in parallel to two ends of the variable frequency start button.

[0025] As a further improvement of the present invention, two ends of another group of normally open contacts of the variable frequency operation relay are respectively connected to the terminal 10 and the terminal 13 of the ACS-510 inverter.

[0026] As a further improvement of the present invention, the power frequency operation control circuit includes a power frequency start button, a power frequency stop button and a power frequency operation indicator light;

[0027] One end of the normally closed contact of the power frequency thermal relay is connected to terminal 4 of the power frequency / variable frequency control switch, and the other end is connected to terminals 5 and 7 of the local / remote control switch respectively;

[0028] The outgoing line of terminal 6 of the local / remote control switch is connected in series with the power frequency stop button and the power frequency start button in sequence;

[0029] The outlet end of terminal 8 of the local / remote control switch is connected in series with the normally open contact of the remote operation command relay. The outlet end of the normally open contact of the remote operation command relay is connected in parallel with the outlet end of the power frequency start button and then connected in series with the normally closed contact of the variable frequency isolation contactor and one end of the coil of the power frequency contactor. The other end of the coil of the power frequency contactor is connected to the neutral line in the cabinet.

[0030] The two ends of the coil of the power frequency contactor are also connected in parallel with the power frequency operation indicator light, and the two ends of the normally open contact of the power frequency contactor are connected in parallel with the two ends of the power frequency start button;

[0031] Terminals 1 and 3 of the industrial frequency / variable frequency control switch are connected to the live wire in the cabinet through the single-pole circuit breaker.

[0032] As a further improvement of the present invention, it also includes a cooling fan, a variable frequency stop indicator light and a power frequency stop indicator light;

[0033] The cooling fan is fixedly mounted on the top of the frequency conversion cabinet to dissipate heat for the frequency converter;

[0034] The positive pole outgoing line of the cooling fan is connected in series with a set of normally open contacts of the variable frequency operation relay and then connected to the live wire in the cabinet through the single-pole circuit breaker, and the negative pole outgoing line of the cooling fan is connected to the neutral wire in the cabinet;

[0035] The positive output line of the frequency conversion stop indicator light is connected in series with a set of normally closed contacts of the frequency conversion operation status relay and then connected to the live wire in the cabinet through the single-pole circuit breaker, and the negative output line of the frequency conversion stop indicator light is connected to the neutral wire in the cabinet;

[0036] The positive output line of the power frequency stop indicator light is connected in series with a group of normally closed contacts of the power frequency contactor and then connected to the live wire in the cabinet through the single-pole circuit breaker, and the negative output line of the power frequency stop indicator light is connected to the neutral wire in the cabinet.

[0037] As a further improvement of the present invention, the temperature setting value of the rotor cooling air in the remote TCS system is 200°C.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] The present invention connects a blower motor in a rotor cooling air cooler to a frequency conversion system, and realizes variable frequency or industrial frequency operation of the blower motor through a variable frequency operation control circuit and an industrial frequency operation control circuit. By providing two parallel local control branches and a remote control branch in each of the variable frequency operation control circuit and the industrial frequency operation control circuit, remote / local control of the blower motor under variable frequency or industrial frequency can be realized, which facilitates the operation of the operator, realizes variable frequency control of the blower motor of the rotor cooling air cooler, and achieves precise control of the rotor cooling air temperature.

[0040] The present invention connects the analog input channel of the frequency converter with the analog output channel of the remote TCS system, and connects the analog input channel of the remote TCS system with the temperature sensor in the rotor cooling air cooler. Thus, the air temperature in the rotor cooling air cooler can be monitored in real time by the remote TCS system. Then, the PID regulator in the remote TCS system is used to adjust the temperature, thereby controlling the rotor cooling to an appropriate temperature, reducing the second-stage wheel gap temperature, protecting the gas turbine hot components, and ensuring safe and stable operation of the gas turbine. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a schematic diagram of the wiring of the electrical system inside the frequency conversion cabinet of the frequency conversion system of the gas turbine rotor cooling air cooler blower disclosed in one embodiment of the present invention;

[0042] Figure 2 A schematic diagram of the internal electrical secondary wiring of a frequency conversion cabinet of a gas turbine rotor cooling air cooler blower frequency conversion system disclosed in one embodiment of the present invention;

[0043] Figure 3 A diagram showing the adjustment principle of a PID regulator for a frequency conversion system of a gas turbine rotor cooling air cooler blower disclosed in one embodiment of the present invention;

[0044] Figure 4 A comparison curve diagram of the rotor cooling air temperature and the second-stage disc gap temperature after the blower motor stops in the prior art;

[0045] Figure 5 A statistical diagram of the two-stage disc clearance temperature of a gas turbine rotor cooling air cooler blower frequency conversion system disclosed in one embodiment of the present invention.

[0046] In the picture:

[0047] 1. PID regulator; 2. Remote TCS system; 3. Frequency converter. DETAILED DESCRIPTION

[0048] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0049] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0050] In the description of the present invention, it should also be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0051] The present invention is described in further detail below with reference to the accompanying drawings:

[0052] like Figure 1-2 As shown, the present invention discloses a frequency conversion system for a gas turbine rotor cooling air cooler blower, comprising a frequency conversion cabinet, in which a frequency converter 3, a power frequency contactor KM1, a frequency conversion isolation contactor KM2, and a control circuit are installed; the input end of the frequency converter 3 is connected to a 380V three-phase AC power supply through a power supply line switch 1QF, the output end of the frequency converter 3 is connected to a blower motor M in the rotor cooling air cooler through a normally open contact of the frequency conversion isolation contactor KM2 to form a frequency conversion circuit, the input end of the blower motor M is connected to a 380V three-phase AC power supply through the normally open contact of the power frequency contactor KM1 and the power supply line switch 1QF to form a power frequency circuit, the power frequency contactor KM1 and the frequency conversion isolation contactor KM2 are electrically interlocked, and the power supply line switch 1QF in the present invention can be a molded case circuit breaker;

[0053] The control circuit includes a variable frequency operation control circuit and a power frequency operation control circuit. The variable frequency operation control circuit and the power frequency operation control circuit are switched by the power frequency / variable frequency control switch SA1 to put the blower motor into variable frequency or power frequency operation;

[0054] The variable frequency operation control circuit and the power frequency operation control circuit are both equipped with two parallel local control branches and remote control branches, which are switched by the local / remote control switch SA2;

[0055] The analog input channel of the inverter 3 is connected to the analog output channel of the remote TCS system 2. The remote TCS system 2 obtains the temperature of the rotor cooling air in the rotor cooling air cooler in real time. The PID regulator 1 in the remote TCS system 2 is used to calculate the deviation between the temperature of the rotor cooling air and the set value. The remote TCS system 2 adjusts the frequency of the inverter 3 in real time through the PID regulator 1.

[0056] Furthermore, during actual connection, the analog input channel of the inverter 3 is connected to the analog output channel of the remote TCS system 2, the analog input channel of the remote TCS system 2 is connected to the temperature sensor in the rotor cooling air cooler, the PID regulator 1 in the remote TCS system 2 is used to calculate the deviation between the measured value of the temperature sensor and the set value, and the remote TCS system 2 adjusts the frequency of the inverter 3 through the PID regulator 1.

[0057] Specifically:

[0058] like Figure 1 As shown, the power frequency circuit in the present invention further includes a power frequency thermal relay FR1, which is connected in series between the input end of the blower motor M and the normally open contact of the power frequency contactor KM1.

[0059] Furthermore, the inverter 3 in the present invention is an ACS-510 inverter, and terminals 2 and 3 of the ACS-510 inverter are connected to the analog output channel of the remote TCS system 2; terminals 22 and 25 of the ACS-510 inverter are short-circuited and connected to the live wire L in the cabinet through a single-pole circuit breaker, terminal 24 of the ACS-510 inverter is connected to one end of the coil of the frequency conversion fault action relay KA1, and terminal 27 of the ACS-510 inverter is connected to one end of the coil of the frequency conversion operation status relay KA2. The other ends of the coil of the frequency conversion fault action relay KA1 and the coil of the frequency conversion operation status relay KA2 are both connected to the neutral wire N in the cabinet; the two ends of the coil of the frequency conversion fault action relay KA1 are connected in parallel with the frequency conversion fault indicator light HY1, and the two ends of the coil of the frequency conversion operation status relay KA2 are connected in parallel with the frequency conversion operation indicator light HR1.

[0060] Further, such as Figure 2-3 As shown, terminals 2 and 3 of the ACS-510 inverter in the present invention are connected to the analog output channels of the remote TCS system 2, and the analog input channels of the remote TCS system 2 are connected to the temperature sensor in the rotor cooling air cooler. The remote TCS system 2 can monitor the rotor cooling air temperature, i.e., the RCA temperature, in real time, and calculate the deviation between the temperature sensor's measured value and the set value through the PID regulator 1 within the remote TCS system 2. When the blower motor M is put into variable frequency operation mode, the remote TCS system 2 compares the real-time RCA temperature with the set value of 200°C. The deviation between the measured value and the set value serves as the controlled variable of the PID regulator. After calculation by the PID regulator 1, it is converted into a frequency command for the blower motor M. The inverter 3 will adjust the frequency output of the inverter 3 in real time according to the command signal from the remote TCS system 2. When the blower motor M is put into power frequency operation mode, the frequency command of the blower motor M is switched to 50Hz, enabling the remote TCS system 2 to accurately control the rotor cooling air temperature. In the present invention, the real-time adjustment of the frequency of the frequency converter 3 by using a PID regulator is a prior art and will not be described in detail here.

[0061] Furthermore, the DO1 channel of the remote TCS system 2 in the present invention is connected to one end of the coil of the remote operation command relay KA4, the other end of which is connected to the live wire L in the cabinet via a single-pole circuit breaker. The variable frequency operation control circuit includes a variable frequency start button SB1, a variable frequency stop button SB2, and a variable frequency operation relay KA3; one end of a set of normally closed contacts of the variable frequency fault action relay KA1 is connected to terminal 2 of the power frequency / variable frequency control switch SA1, and the other end is connected to terminals 1 and 3 of the local / remote control switch SA2, respectively. The remote TCS system 2 in the present invention is an existing system and will not be described in detail here.

[0062] Furthermore, the output wire of terminal 2 of the local / remote control switch SA2 in the present invention is connected in series with the variable frequency stop button SB2 and the variable frequency start button SB1, respectively. The output wire of terminal 4 of the local / remote control switch SA2 is connected in series with the normally open contact of the remote operation command relay KA4. The output wire of the normally open contact of the remote operation command relay KA4 is connected in parallel with the output wire of the variable frequency start button SB1 and then connected to one end of the coil of the variable frequency operation relay KA3. The other end of the coil of the variable frequency operation relay KA3 is connected to the neutral line N within the cabinet. The two ends of one set of normally open contacts of the variable frequency operation relay KA3 are connected in parallel with the two ends of the variable frequency start button SB1 to form an electrical self-locking function for the variable frequency start button SB1. The two ends of the other set of normally open contacts of the variable frequency operation relay KA3 are connected to terminals 10 and 13 of the ACS-510 inverter, respectively, to control the start and stop of the inverter 3 by closing and opening the normally open contacts of the variable frequency operation relay KA3.

[0063] Furthermore, the power frequency operation control circuit in the present invention includes a power frequency start button SB3, a power frequency stop button SB4 and a power frequency operation indicator light HR2; one end of the normally closed contact of the power frequency thermal relay FR1 is connected to the terminal 4 of the power frequency / variable frequency control switch, and the other end is respectively connected to the terminals 5 and 7 of the local / remote control switch SA2; the outgoing line of the terminal 6 of the local / remote control switch SA2 is connected in series with the power frequency stop button SB4 and the power frequency start button SB3 in sequence; the outgoing line end of the terminal 8 of the local / remote control switch SA2 is connected in series with the normally open contact of the remote operation command relay KA4, the outgoing line end of the normally open contact of the remote operation command relay KA4 is connected in parallel with the outgoing line end of the power frequency start button SB3, and then connected in series with the normally closed contact of the variable frequency isolation contactor KM2 and one end of the coil of the power frequency contactor KM1, and the other end of the coil of the power frequency contactor KM1 is connected to the neutral line N in the cabinet;

[0064] Furthermore, the two ends of the coil of the power frequency contactor KM1 in the present invention are also connected in parallel with the power frequency operation indicator light HR1, and the two ends of the normally open contact of the power frequency contactor KM1 are connected in parallel to the two ends of the power frequency start button SB3 to achieve electrical self-locking of the power frequency start button SB3; terminals 1 and 3 of the power frequency / variable frequency control switch SA1 are both connected to the live wire L in the cabinet through a single-pole circuit breaker.

[0065] Furthermore, the present invention also includes a cooling fan F, a frequency conversion stop indicator light HG1, and a power frequency stop indicator light HG2; the cooling fan F is fixedly installed on the cabinet top of the frequency conversion cabinet body and is used to dissipate heat for the frequency converter 3; the positive pole output line of the cooling fan F is connected in series with a set of normally open contacts of the frequency conversion operation relay KA3 and then connected to the live wire L in the cabinet through a single-pole circuit breaker, and the negative pole output line of the cooling fan F is connected to the neutral wire N in the cabinet;

[0066] The positive output line of the frequency conversion stop indicator light HG1 is connected in series with a set of normally closed contacts of the frequency conversion operation status relay KA2, and then connected to the live wire L in the cabinet through a single-pole circuit breaker. The negative output line of the frequency conversion stop indicator light HG1 is connected to the neutral wire N in the cabinet.

[0067] The positive output line of the power frequency stop indicator light HG2 is connected in series with a group of normally closed contacts of the power frequency contactor KM1 and then connected to the live wire L in the cabinet through a single-pole circuit breaker. The negative output line of the power frequency stop indicator light HG2 is connected to the neutral wire N in the cabinet.

[0068] Furthermore, in the present invention, a control panel can be installed in the frequency conversion cabinet, and the industrial frequency / converter frequency control switch SA1, the local / remote control switch SA2, the frequency conversion stop indicator light HG1, the industrial frequency stop indicator light HG2, the frequency conversion operation indicator light HR1, the industrial frequency operation indicator light HR2, the frequency conversion fault indicator light HY1, the frequency conversion start button SB1, the frequency conversion stop button SB2, the industrial frequency start button SB3, and the industrial frequency stop button SB4 are all fixedly installed on the control panel.

[0069] Furthermore, the present invention also includes a distribution cabinet, which is used to provide a 380V three-phase AC power supply to the inside of the frequency conversion cabinet. In the present invention, the live wire L and the neutral wire N inside the frequency conversion cabinet can be composed of any phase and neutral wire in the 380V three-phase AC power supply, or the live wire L and the neutral wire N can be directly provided to the frequency conversion cabinet through the distribution cabinet.

[0070] like Figure 1-3 As shown, the working method of the rotor cooling air cooler blower motor M of the present invention includes two operating states: variable frequency and industrial frequency. The variable frequency operation method of the blower motor M includes:

[0071] 1. Turn the power frequency / variable frequency control switch SA1 to the variable frequency position and confirm that the inverter has no fault alarm, that is, the variable frequency fault indicator HY1 is not lit;

[0072] 2. After turning the local / remote control switch SA2 to the local position, press the frequency conversion start button SB1. The frequency conversion operation relay KA3 will operate and self-hold, starting the inverter 3 and the blower motor M;

[0073] 3. Press the frequency conversion stop button SB2, the frequency conversion operation relay KA3 is reset, the frequency converter 3 stops, and the blower motor M stops;

[0074] 4. After turning the local / remote control switch SA2 to the remote position, the remote TCS system 2 controls the coil of the remote operation command relay KA4 to be energized, the frequency conversion operation relay KA3 to operate, the inverter 3 to start the blower motor M, and the remote TCS system 2 obtains the RCA temperature in real time. The remote TCS system 2 compares the real-time RCA temperature with the set value of 200°C for deviation. The deviation between the measured value and the set value is used as the controlled variable of the PID regulator 1. After calculation by the PID regulator 1, it is converted into the frequency command of the blower motor M. The inverter 3 will adjust the frequency output of the inverter 3 in real time according to the command signal of the remote TCS system 2;

[0075] 5. When the remote TCS system 2 does not send a start command, the remote operation command relay KA4 is de-energized, the variable frequency operation relay KA3 is reset, and the blower motor M stops.

[0076] Furthermore, the power frequency operation method of the blower motor M of the present invention includes:

[0077] 1. Turn the power frequency / variable frequency control switch SA1 to the power frequency position and confirm that the power frequency thermal relay FR1 is not actuated;

[0078] 2. After turning the local / remote control switch SA2 to the local position, press the power frequency start button SB3, the power frequency contactor KM1 will operate and self-hold, and the blower motor M will run; press the power frequency stop button SB4, the power frequency contactor KM1 will reset, and the blower motor M will stop;

[0079] 3. After turning the local / remote control switch SA2 to the remote position, the remote TCS system 2 controls the remote operation command relay KA4 coil to be energized, the power frequency contactor KM1 is activated, and the blower motor M starts to run at the power frequency of 50Hz;

[0080] 4. When the remote TCS system 2 does not send a start command, the remote operation command relay KA4 is de-energized, the power frequency contactor KM1 is reset, and the blower motor M stops;

[0081] 5. When the power frequency operating current of the blower motor M is greater than the action value, the power frequency thermal relay FR1 will operate, the power frequency contactor KM1 will reset, and the blower motor M will stop.

[0082] like Figure 5 As shown, by performing variable frequency control on a blower motor M in the rotor cooling air cooler, the present invention can achieve precise control of the rotor cooling air temperature (RCA), so that the temperature of the gas turbine second-stage wheel clearance (2DCT) can be controlled; the temperature of the gas turbine second-stage wheel clearance (2DCT) can be stabilized below 430°C throughout the heating season, which is far below the alarm value of 460°C.

[0083] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A gas turbine rotor cooling air cooler blower frequency conversion system, characterized in that: It includes a frequency conversion cabinet, in which a frequency converter, a power frequency contactor, a frequency conversion isolation contactor and a control circuit are installed; The input end of the frequency converter is connected to a 380V three-phase AC power supply through a power supply line switch, the output end of the frequency converter is connected to a blower motor in a rotor cooling air cooler through a normally open contact of a frequency conversion isolation contactor to form a frequency conversion circuit, and the input end of the blower motor is connected to a 380V three-phase AC power supply through a normally open contact of a power frequency contactor and a power supply line switch to form a power frequency circuit, and the power frequency contactor and the frequency conversion isolation contactor are electrically interlocked; The control circuit includes a variable frequency operation control circuit and a power frequency operation control circuit, and the variable frequency operation control circuit and the power frequency operation control circuit are switched by a power frequency / variable frequency control switch to enable the blower motor to operate in variable frequency or power frequency; The variable frequency operation control circuit and the power frequency operation control circuit are both provided with two parallel local control branches and remote control branches, and the local control branch and the remote control branch are switched by a local / remote control switch; The analog input channel of the frequency converter is connected to the analog output channel of the remote TCS system. The remote TCS system obtains the temperature of the rotor cooling air in the rotor cooling air cooler in real time. The PID regulator in the remote TCS system is used to calculate the deviation between the temperature of the rotor cooling air and a set value. The remote TCS system adjusts the frequency of the frequency converter in real time through the PID regulator. The power frequency circuit further includes a power frequency thermal relay, which is connected in series between the input end of the blower motor and the normally open contact of the power frequency contactor; The frequency converter is an ACS-510 frequency converter, and terminals 2 and 3 of the ACS-510 frequency converter are connected to the analog output channel of the remote TCS system; Terminals 22 and 25 of the ACS-510 inverter are short-circuited and connected to the live wire in the cabinet via a single-pole circuit breaker. Terminal 24 of the ACS-510 inverter is connected to one end of the coil of the frequency conversion fault action relay. Terminal 27 of the ACS-510 inverter is connected to one end of the coil of the frequency conversion operation status relay. The other ends of the coils of the frequency conversion fault action relay and the frequency conversion operation status relay are both connected to the neutral wire in the cabinet. Both ends of the coil of the frequency conversion fault action relay are connected in parallel with frequency conversion fault indicator lights, and both ends of the coil of the frequency conversion operation status relay are connected in parallel with frequency conversion operation indicator lights.

2. A gas turbine rotor cooling air cooler blower frequency conversion system according to claim 1, characterized in that: The DO1 channel of the remote TCS system is connected to one end of the coil of the remote operation command relay, and the other end of the coil of the remote operation command relay is connected to the live wire in the cabinet through the single-pole circuit breaker.

3. A gas turbine rotor cooling air cooler blower frequency conversion system according to claim 2, characterized in that: The variable frequency operation control circuit includes a variable frequency start button, a variable frequency stop button, and a variable frequency operation relay; One end of a group of normally closed contacts of the variable frequency fault action relay is connected to terminal 2 of the power frequency / variable frequency control switch, and the other end is connected to terminal 1 and terminal 3 of the local / remote control switch respectively; The outgoing line of terminal 2 of the local / remote control switch is connected in series with the frequency conversion stop button and the frequency conversion start button in sequence; The output terminal of terminal 4 of the local / remote control switch is connected in series with the normally open contact of the remote operation command relay. The output terminal of the normally open contact of the remote operation command relay is connected in parallel with the output terminal of the frequency conversion start button and then connected to one end of the coil of the frequency conversion operation relay. The other end of the coil of the frequency conversion operation relay is connected to the neutral line in the cabinet. Two ends of a group of normally open contacts of the variable frequency operation relay are connected in parallel to two ends of the variable frequency start button.

4. A gas turbine rotor cooling air cooler blower frequency conversion system according to claim 3, characterized in that: The two ends of another group of normally open contacts of the variable frequency operation relay are respectively connected to the terminal 10 and the terminal 13 of the ACS-510 inverter.

5. A gas turbine rotor cooling air cooler blower frequency conversion system according to claim 3, characterized in that: The power frequency operation control circuit includes a power frequency start button, a power frequency stop button and a power frequency operation indicator light; One end of the normally closed contact of the power frequency thermal relay is connected to terminal 4 of the power frequency / variable frequency control switch, and the other end is connected to terminals 5 and 7 of the local / remote control switch respectively; The outgoing line of terminal 6 of the local / remote control switch is connected in series with the power frequency stop button and the power frequency start button in sequence; The outlet end of terminal 8 of the local / remote control switch is connected in series with the normally open contact of the remote operation command relay. The outlet end of the normally open contact of the remote operation command relay is connected in parallel with the outlet end of the power frequency start button and then connected in series with the normally closed contact of the variable frequency isolation contactor and one end of the coil of the power frequency contactor. The other end of the coil of the power frequency contactor is connected to the neutral line in the cabinet. The two ends of the coil of the power frequency contactor are also connected in parallel with the power frequency operation indicator light, and the two ends of the normally open contact of the power frequency contactor are connected in parallel with the two ends of the power frequency start button; Terminals 1 and 3 of the industrial frequency / variable frequency control switch are connected to the live wire in the cabinet through the single-pole circuit breaker.

6. A gas turbine rotor cooling air cooler blower frequency conversion system according to claim 5, characterized in that: It also includes a cooling fan, a variable frequency stop indicator light, and a power frequency stop indicator light; The cooling fan is fixedly mounted on the top of the frequency conversion cabinet to dissipate heat for the frequency converter; The positive pole outgoing line of the cooling fan is connected in series with a set of normally open contacts of the variable frequency operation relay and then connected to the live wire in the cabinet through the single-pole circuit breaker, and the negative pole outgoing line of the cooling fan is connected to the neutral wire in the cabinet; The positive output line of the frequency conversion stop indicator light is connected in series with a set of normally closed contacts of the frequency conversion operation status relay and then connected to the live wire in the cabinet through the single-pole circuit breaker, and the negative output line of the frequency conversion stop indicator light is connected to the neutral wire in the cabinet; The positive output line of the power frequency stop indicator light is connected in series with a group of normally closed contacts of the power frequency contactor and then connected to the live wire in the cabinet through the single-pole circuit breaker, and the negative output line of the power frequency stop indicator light is connected to the neutral wire in the cabinet.

7. A gas turbine rotor cooling air cooler blower frequency conversion system according to claim 1, characterized in that: The rotor cooling air temperature set point in the remote TCS system is 200°C.

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