KR20200049292A - Secondary control method for start-up equipment of gas turbine - Google Patents

Abstract

The present invention relates to a control method for a gas turbine starting device including first and second main controllers. The method comprises the steps of: selecting the first main controller to start a gas turbine when the power of the starting device is activated; performing communication with a plurality of control boards using a first communication hub in a state in which the first main controller is selected; determining whether the first main controller has failed, by using the information received through the first communication hub; switching a control means of the starting device from the first main controller to the second main controller to stop the starting device, when it is determined that the first main controller has failed; monitoring the speed of the gas turbine in the state in which the control means is switched to the second main controller; and restarting the starting device based on the speed of the gas turbine.

Description

Gas turbine starting device auxiliary control method {SECONDARY CONTROL METHOD FOR START-UP EQUIPMENT OF GAS TURBINE}

The present invention relates to a starting device for speed control of a gas turbine generator and a control method therefor. Specifically, the present invention relates to a starting device for speed control including a main controller and an auxiliary controller.

The gas turbine generator for the power generation industry uses a Brayton cycle power generation method in which a turbine, a compressor, and a synchronous generator are uniaxial. Conventionally, the method of obtaining the rotational force of the gas turbine required in the Brayton cycle method was a method of directly driving the turbine rotor using a torque converter.

Recently, with the rapid development of power conversion technology, technology for driving a large synchronous generator in the form of an electric motor has been applied, and continuous technology development continues. Unlike a steam turbine generator, a large-capacity gas turbine generator with several hundred MW or more can achieve mixed combustion of compressed air and LNG fuel only when the gas turbine rotor composed of a compressor and a body is in a rotational state of a predetermined speed or higher.

It is known that the operation characteristics of a typical gas turbine generator is capable of igniting and maintaining combustion of LNG fuel when it is elevated from 360 rpm to 500 rpm (approximately 10% to 40%) based on the rated speed of 3600 rpm, after which the speed characteristic depends on the amount of fuel supplied. It depends on the combustion gas and the motive force of the synchronous machine.

The role of the starting device is up to approximately 90% of the rated speed, and reaches the rated speed by magnetic force from the combustion gas. As a starting device for the initial start of a gas turbine generator, a stationary load current type inverter system using a thyristor power semiconductor element is commercially available and is in operation. These inverter systems are illustrated in FIGS. 1 and 2.

The starter for speed control of a large-capacity gas turbine generator generates a momentary synchronous voltage when it is switched to a sub-controller after a main controller failure when it is controlled by redundancy.

Due to this technical problem, the starting device for speed control is used as a single controller without using a redundant controller, and when a generator fails, the generator is completely stopped and then repaired.

However, when the generator is completely stopped whenever a failure occurs in the generator, there is a problem that the reliability and safety of the generator cannot be guaranteed. Since such a problem cannot be solved by an existing speed control starting device using a single controller, there is a need for a speed controlling starting device using a plurality of controllers while preventing component burnout.

Therefore, in the present invention, a redundancy control method only for a gas turbine starting device is proposed to solve this problem.

The technical problem of the present invention is to provide a speed control starter and a control method for performing speed control of a gas turbine generator so that repair to the generator is possible while maintaining the operation of the generator even when the generator is broken.

In addition, the technical problem of the present invention, while using a plurality of controllers, to provide a speed control starting device and a control method for preventing burnout of parts of the generator.

In order to achieve the above object, as an aspect, a method for controlling a gas turbine starting device according to the present invention comprises: when the power of the starting device is activated, selecting the first main controller to start the gas turbine, the Performing communication with a plurality of control boards using a first communication hub while the first main controller is selected, and determining whether the first main controller has failed using information received through the first communication hub. Step, if it is determined that the first main controller is broken, switching the control means of the starting device from the first main controller to the second main controller, stopping the starting device, and in the state of switching to the second main controller And monitoring the speed of the gas turbine and restarting the starting device based on the speed of the gas turbine. The.

In one embodiment, after the startup device is restarted, determining whether the second main controller has failed using the information received through the second communication hub, and when it is determined that the second main controller has failed, It characterized in that it further comprises the step of turning off the power of the first and second main controller.

In one embodiment, the step of restarting the starting device is characterized in that if the speed of the gas turbine falls below a preset reference value, the restarting of the starting device is characterized in that.

In one embodiment, the reference value is characterized in that it is set to correspond to the ignition speed of the gas turbine.

In one embodiment, the step of determining whether the first main controller is broken includes: a first process of monitoring the state of the first main controller based on a pulse generated from the first main controller; And a second process of monitoring the state of the first main controller based on the value of the digital signal output by the main controller.

As described above, according to an embodiment of the present invention, while driving the gas turbine generator using the main controller of the starting device, if a failure occurs in the generator, the drive main body of the generator is switched to the auxiliary controller, thereby the gas turbine generator There is an advantage that can minimize the stop of the generator driven by the failure of the.

In addition, by minimizing the stoppage of the generator, it is possible to reduce power plant start-up delays and generator maintenance costs.

In addition, since the generator manager can determine when the generator is repaired outside the peak power period, power supply safety is also improved.

Further, according to the present invention, by using a plurality of controllers, even when a generator failure occurs, since the generator is not completely stopped, an effect of reducing the time required for restarting the generator by several tens of minutes or more is derived.

In addition, according to the present invention, in driving a gas turbine generator, an effect capable of stably driving and stopping the generator while using a plurality of controllers is derived.

1 is a conceptual diagram showing a starting device of a gas turbine generator equipped with a single controller.
2 is a conceptual diagram showing a starting device of a gas turbine generator equipped with a single controller.
3 is a conceptual diagram showing a starting device of a gas turbine generator equipped with a single controller.
4 is a block diagram showing an embodiment of a starting device according to the present invention.
5 is a block diagram showing an embodiment of a starting device according to the present invention.
6 is a block diagram showing an embodiment of a starting device according to the present invention.
7 is a flowchart showing a control method of a starting device according to the present invention.
8 is a graph related to the operation of the starting device according to the present invention.
9 is a view showing a prototype of a starting device according to the present invention.
10 is a graph related to the operation of the starting device according to the present invention.

Hereinafter, the present invention will be described in detail according to the accompanying drawings.

1 to 3 is a conceptual diagram showing a starting device of a gas turbine generator equipped with a single controller.

Referring to FIG. 3, the gas turbine starting device 310 includes a system side converter 301, a DC terminal reactor 302, a motor side converter 303, and a start control unit 330, and the excitation device 320 is And an excitation converter 306 and an excitation system controller.

Hereinafter, the operation of the gas turbine starting device and the excitation device will be described with reference to FIG. 3.

The gas turbine starting device may serve to speed up the gas turbine to a constant rotational speed so that the gas turbine can perform a normal operation when the gas turbine is started. Since the gas turbine is capable of operating on its own because combustion occurs in the combustor when the speed is increased to the initial starting speed or higher, the gas turbine starting device forcibly rotating the gas turbine at the time of starting the gas turbine is It is essential. For example, in the case of a gas turbine generator with a rated speed of 3600 rpm, the gas turbine is in a normal operating state when it is elevated to 2500 to 3000 rpm, and self-burning is possible. Therefore, in order to start the gas turbine generator, it is necessary to first increase the gas turbine to 2500 to 3000 rpm using the gas turbine starting device.

Here, the gas turbine starting device 310 may be implemented as a load current type inverter (LCI: Load Commutated Inverter) utilizing a power semiconductor element such as a thyristor.

Specifically, the gas turbine starting device may receive AC power from the outside through a grid-side converter, and the grid-side converter may rectify the AC power and convert it into DC power. At this time, the start control unit may control the switching operation of the power semiconductor element of the grid-side converter, and the AC power may be converted to the DC power by the switching operation of the power semiconductor element.

Thereafter, the DC power may be input to the motor-side converter via a DC terminal reactor.

The motor-side converter converts the DC power input through the DC terminal reactor into AC and supplies it to the synchronous motor. Here, the motor-side converter may supply stator current that is AC to the stator coil connected to the stator of the synchronous motor, and the stator coil may form a magnetic field by the stator current. In particular, if the stator current supplied by the motor-side converter is adjusted, it is also possible to adjust the size or direction of the magnetic field formed in the stator coil.

Here, the start control unit may control the switching of the power semiconductor element included in the motor-side converter, and control the stator current supplied by the motor-side converter by the switching.

The magnetic field formed in the stator coil may affect a magnetic field formed in a rotor included in the synchronous motor, and torque is applied to the rotor by attraction or repulsive force generated between the magnetic fields. Can be applied. When a torque of a sufficient size is applied to the rotor, the rotor may start to rotate, and when the direction of the magnetic field applied to the stator is changed to a direction that continuously applies torque according to the rotation of the rotor, the rotor rotates Is done.

In the following FIG. 4, the gas turbine starting device duplication method proposed in the present invention will be described.

As illustrated in FIG. 4, the gas turbine upper controller 401 may monitor information related to states of a plurality of control devices provided in the gas turbine starting device through the first communication hub 402. For example, the plurality of control devices may include at least one of a first main controller, a first signal processing and a call signal generator, an excitation system controller, an input / output board, and a driving screen.

Hereinafter, starting the gas turbine using the first main controller is defined as the first operation mode of the gas turbine starting device, and starting the gas turbine using the second main controller is defined as the second operation mode.

Specifically, when the gas turbine is first started, the gas turbine starting device may be driven in the first operation mode. Further, when the starting device of the gas turbine is in a normal state, the gas turbine starting device may be driven in the first operation mode.

In one embodiment, when the gas turbine starting device is operating in the first operation mode, the gas turbine upper controller 401 is based on information collected through the first communication hub 402, and at least one of the plurality of control devices Can determine whether is abnormal. In addition, when it is determined that at least one of the plurality of control devices is abnormal, the gas turbine upper level controller 401 may switch to the second operation mode of driving the gas turbine using the second main controller.

When switching from the first operation mode to the second operation mode, the gas turbine upper controller 401 may communicate with the plurality of control devices using a second communication hub. That is, in the second operation mode of the gas turbine starting device, the gas turbine upper controller 401 determines whether at least one of the plurality of control devices is abnormal based on the information collected through the second communication hub 402. can do.

On the other hand, when switching from the first operation mode to the second operation mode, the gas turbine upper controller 401 changes all control signals to a low value to stop the gas turbine starting device and opens the excitation breaker. Can be.

In the case of a large-capacity gas turbine generator, even if all control signals are changed to a zero value, due to the high inertia of the generator itself, the speed of the turbine stops gradually over several tens of minutes.

The gas turbine starting apparatus according to the present invention may determine a restart time using the second main controller in consideration of the fact that the gas turbine is ignited when the speed of the gas turbine is higher than a predetermined ignition speed.

That is, the gas turbine upper controller 401 restarts the gas turbine generator as the second main controller when the speed of the gas turbine is equal to or less than a preset reference speed in order to secure the safety of the gas turbine generator. For example, the reference speed can be set to about 1000 rpm. The reference speed may be variably set according to the ignition characteristics of the gas turbine generator.

Further, the gas turbine upper level controller 401 may block control signals output from the first signal processing and the call signal generator during restart using the second main controller.

For example, the gas turbine upper level controller 401 prevents the first signal processing and the optical call signal generated by the call signal generator from being input to the call signal distributor of the converter, so that the first signal processing and the call signal generator and the converter call Circuits between signal splitters can be cut off.

Referring to Fig. 5, a starting device driven by a first main controller is described.

As shown in FIG. 5, the first main controller may receive a speed command from the gas turbine upper level controller 401. In addition, the first main controller may communicate with the upper level controller, the operation screen, the input / output board, the first signal processing and the call signal generator, and the excitation system controller through the first communication hub.

In one example, the information received by the first main controller through the first communication hub is related to the integrity and operation command of at least one of an upper level controller, an operation screen, an input / output board, a first signal processing and a call signal generator, and an excitation system controller. Information may be included.

The gas turbine upper level controller 401 may transmit a selection signal corresponding to any one of the first and second main controllers to the converter, inverter, and excitation system, respectively. The converter, the inverter, and the excitation system may determine the final call command based on the selection signal received from the upper controller 401, respectively.

The gas turbine starting device has a large-capacity power conversion device. Accordingly, since the current flowing in the starting device is thousands of amperes or more, the safety of the starting device is very important.

As illustrated in FIG. 6, the gas turbine upper level controller 401 is a distributed controller that controls the entire power plant, and processes information related to gas turbine operation.

Specifically, the gas turbine upper level controller 401 may output first and second selection signals respectively corresponding to the first and second main controllers. At this time, the first selection signal indicates whether the first main controller is selected, and the second selection signal indicates whether the second main controller is selected.

In one embodiment, when the gas turbine upper controller 401 fails in the first main controller of the starting device, the second selection signal is set to 1 value (High Signal), and the first selection signal is 0 value (Low Signal). ). By setting the first and second selection signals, the call signal of the excitation system, the starter converter, and the inverter call signal are controlled by the second signal processing and the call signal output from the call signal generator. At this time, signals output from the first signal processing and the call signal generator are blocked.

By selecting and driving the first and second main controllers in the same manner as described above, it is possible to improve the stability of the gas turbine starting device.

Further, referring to FIG. 6, the gas turbine upper level controller 401 monitors the states of the first and second main controllers of the starting device.

In one embodiment, the gas turbine upper controller 401 determines whether the states of the first and second main controllers are normal based on an ODS (OS Diagnostic Selector) signal output by the first and second main controllers, respectively. can do.

For example, the ODS signal is set to output a value of 1 when the S / W logic inside the controller is normal.

In another embodiment, the upper turbine controller 401 may determine whether the states of the first and second main controllers are normal based on the pulse signals output from the first and second main controllers, respectively.

For example, the first and second main controllers are set to generate digital pulses at predetermined periods, respectively. Therefore, the gas turbine upper level controller 401 may set the pulse check signal to a zero value when a pulse signal is not generated from the main controller while the period has elapsed multiple times.

In addition, the upper control unit 401 of the gas turbine configures communication with the lower control board, and when a problem occurs in the communication, a controller switching occurs.

On the other hand, if a failure occurs while driving the generator with the second main controller after the first main controller has failed, the gas turbine upper controller may set both the first and second selection signals to zero values. In this case, regardless of the operation of the main controller of the starter, the starter converter and the inverted signal of the inverter become 0, so that no current flows, so that the input / output large breaker can be opened. Similarly, all signals corresponding to the first and second selection signals are also set to 0 as the optical signal output from the excitation controller, and the excitation system's call signal is also set to 0, so that the field breaker can be stably opened.

Hereinafter, in FIG. 7, a control method of a gas turbine starting apparatus proposed in the present invention will be described.

First, when driving of the gas turbine is started, the power of the first and second main controllers is activated (S701).

At this time, the gas turbine upper controller 401 is a subject that starts the gas turbine, selects a first main controller (S702), and may communicate with a plurality of control devices using a first communication hub (S703).

Specifically, the gas turbine upper level controller 401 sets the first selection signal to a value of 1, and sets the second selection signal to a value of 0. Thereafter, the gas turbine upper controller 401 may start communication with the lower boards through the first communication hub, and if there is no abnormality in the lower board, the starting device may be controlled to start gas turbine starting.

As described above, the gas turbine upper level controller 401 may activate the gas turbine by using the first main controller and the first communication hub when the gas turbine is started or the gas turbine is normally operating (S704). ). That is, the gas turbine upper level controller 401 may preferentially select the first main controller.

On the other hand, the gas turbine upper controller 401 may determine whether the first main controller has failed using the information obtained through the first communication hub (S705).

If it is determined that the first main controller is broken, the gas turbine upper controller 401 may select the second main controller (S706) and perform communication with a plurality of control devices using the second communication hub (S707).

In addition, after the second main controller is selected, the gas turbine upper controller 401 may stop the operation of the gas turbine starting device (S708), and calculate the rotational speed of the gas turbine (S709).

In particular, the gas turbine upper level controller 401 may determine whether the calculated rotational speed is smaller than a preset reference value (S710).

Specifically, the gas turbine upper controller 401 may monitor the speed of the gas turbine after being switched to the second driving mode for selecting the second main controller. The gas turbine upper level controller 401 calculates the speed of the gas turbine every predetermined period until the speed of the gas turbine falls below the reference value. In one example, the reference value may be set to 1000 Rpm. In another example, the reference value may be set to the ignition speed of the gas turbine.

As described above, by performing the step of calculating the rotational speed of the gas turbine (S709) and the step of comparing the rotational speed with a reference value (S710), the restart time of the gas turbine can be determined (S711).

That is, after the second main controller is selected, the gas turbine upper level controller 401 may control the operation of the gas turbine so that the gas turbine restarts when the speed of the gas turbine falls below the ignition speed.

During the restart of the gas turbine, the gas turbine upper controller 401 may determine whether the second main controller has failed (S712). If it is determined that a failure occurs in the second main controller in the process of restarting the gas turbine, the gas turbine upper controller 401 may deselect both the first and second main controllers (S713).

That is, when the second main controller is also broken in the process of restarting the gas turbine, the gas turbine upper controller 401 stops the starting device of the gas turbine again (S714), and can turn off the power of the first and second main controllers. Yes (S715). When both the first and second selection signals corresponding to the first and second main controllers are set to a value of 0, the output power of the starting device and the excitation system is blocked, so that the starting device can be stably stopped.

8 is a graph showing the gas turbine speed over time.

Referring to FIG. 8, when a first main controller fails, a subject performing control of the starting device is switched to the second main controller, and the starting device is stopped.

In addition, when the speed of the gas turbine becomes less than the ignition speed, the motor starts to start again, and if a separate failure does not occur in the second main controller, it stops at the target speed.

On the other hand, after a restart, if the second controller fails, the first and second selection signals are set to zero, and the starter and the excitation system breaker are opened.

9 and 10 show photographs and waveforms produced and tested by a prototype of a maneuvering device. If a failure occurs in the first main controller, as shown in FIG. 10, the second main controller 2 is switched and the speed can be increased without completely stopping the gas turbine.

Claims (5)

In the control method of the gas turbine starting apparatus comprising a first main controller and a second main controller,
When the power of the starting device is activated, selecting the first main controller to start a gas turbine;
Performing communication with a plurality of control boards using a first communication hub while the first main controller is selected;
Determining whether the first main controller has failed using the information received through the first communication hub;
If it is determined that the first main controller is broken, switching control means of the starting device from the first main controller to the second main controller, and stopping the starting device;
Monitoring the speed of the gas turbine in the state of being switched to the second main controller; And
And restarting the starting device based on the speed of the gas turbine. According to claim 1,
Determining whether the second main controller has failed using the information received through the second communication hub after the startup device is restarted; And
If it is determined that the second main controller is broken, the control method of the gas turbine starting device further comprising the step of turning off the power of the first and second main controller. According to claim 1,
Restarting the starting device,
And when the speed of the gas turbine falls below a preset reference value, restarting the starting device. According to claim 3,
The reference value is a control method of a gas turbine starting device, characterized in that is set to correspond to the ignition speed of the gas turbine. According to claim 1,
The step of determining whether the first main controller is broken,
A first process of monitoring a state of the first main controller based on a pulse generated from the first main controller;
And a second process of monitoring the state of the first main controller based on the value of the digital signal output by the first main controller.

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