JP6101787B2 - Power generation system and method for controlling power generation system - Google Patents

Description

The present invention relates to a power generation system, and more particularly to a power generation system that starts in cooperation with a system.

  There is a problem that the system voltage fluctuates due to renewable energy, and a highly reliable power generation system corresponding to these problems is demanded. For example, since a gas turbine power generation system generally has a shorter start-up time than a steam turbine power generation system, it is expected to contribute to system stabilization when introducing renewable energy by a short start-up. In particular, the twin-shaft gas turbine is compact and capable of generating a large output, and Japanese Patent Publication No. 2007-505261 (Patent Document 1) is known as a method for improving the performance of the twin-shaft gas turbine. Patent Document 1 describes an apparatus in which a generator is attached to both shafts of a two-shaft gas turbine and electric power is obtained from both the generators.

  The gas turbine starting method is described in, for example, Japanese Patent Laid-Open No. 6-264766 (Patent Document 2) and Japanese Patent Publication No. 59-9737 (Patent Document 3). That is, the compressor and the first turbine are rotated by the starter motor, and after the rotational speed has increased to a predetermined value, the fuel is ignited to obtain the compressor driving force. Then, adjust the fuel and intake air amount to increase the number of revolutions to the rated number of revolutions, and after the grid voltage of the grid and the terminal voltage phase difference of the generator are within the specified range, between the generator and the power grid The installed circuit breaker is inserted and the grid connection of the gas turbine power generation system is terminated.

  By introducing the circuit breaker after reducing the phase difference, it is possible to avoid outflow of excessive current from the generator during grid connection and fluctuations in grid voltage during grid connection.

Special table 2007-505261 JP-A-6-264766 Japanese Patent Publication No.59-9737

  Regardless of the magnitude of the output command value, the inverter starts voltage switching (hereinafter referred to as deblocking), causing voltage pulsation both upstream and downstream, and as a result, harmonic current flows. This harmonic current has a problem of causing a loss in a device connected to the inverter. Considering a system where the main generator and auxiliary power supply are connected in parallel and the auxiliary power supply is connected to the system via an inverter, the problem is that the harmonic current of the auxiliary power supply inverter flows into the main generator. is there. The rate at which this harmonic current flows into the main generator and the system is inversely proportional to the respective impedances of the main generator and the system connected in parallel as viewed from the inverter. Usually, the impedance of the main generator is larger than that of the system side, and when the system is connected, the harmonic current flowing into the generator is small, so the loss is small and there are few problems. However, in a state where the system side is disconnected, for example, at the time of startup or standby, all the harmonic currents of the inverter flow into the main generator, causing loss. For this reason, there is a problem that impairs the efficiency of the power generation system and the reliability of the generator.

In order to solve the above problems, for example, the configuration described in the claims is adopted. The present application includes a plurality of means for solving the above-described problems. For example, a power source, a generator driven by the power source, and a first provided between the generator and the AC system. With a circuit breaker,
A power converter connected between the generator and the first circuit breaker; a second circuit breaker provided between the first circuit breaker and the power converter; and A power generation system including a deblocker and a controller for controlling opening and closing of the first circuit breaker and the second circuit breaker, wherein the control device includes the first circuit breaker and the second circuit breaker. When the deblocking command of the power conversion unit is output in a state where is open, the closing command for the second circuit breaker is issued after the closing command for the first circuit breaker is issued. Features.

  According to the power generation system of the present invention, it is possible to suppress a current from flowing from the inverter to the main generator, reduce the loss of the main generator during start-up, stop, and standby, and improve the reliability of the power generation system.

Further, according to the power generation system of the present invention, when the inverter is deblocked and the inverter and the main generator are connected, the inverter and the main generator are connected to the system at the same time. It is possible to suppress the increase in the loss of the main generator mainly flowing in the system, and to perform highly efficient operation.

It is explanatory drawing of 1st Example of this invention. It is explanatory drawing of the control method of 1st Example of this invention. 1 is an explanatory diagram of a gas turbine 2 constituting a first embodiment of the present invention. It is explanatory drawing of 2nd Example of this invention. It is explanatory drawing of the control method of 2nd Example of this invention. It is explanatory drawing of the alternative of this invention 2nd Example. It is explanatory drawing of 3rd Example of this invention. It is explanatory drawing of the control method of 3rd Example of this invention. It is explanatory drawing of the alternative of 3rd Example of this invention. It is explanatory drawing of 4th Example of this invention. It is explanatory drawing of the alternative of 4th Example of this invention. It is explanatory drawing of 5th Example of this invention. It is explanatory drawing of the inverter 5 which comprises 5th Example of this invention. It is explanatory drawing of the alternative of the inverter 5 which comprises 5th Example of this invention. It is explanatory drawing of the control method of 5th Example of this invention. It is explanatory drawing of the control method of 6th Example of this invention.

  Hereinafter, examples will be described with reference to the drawings.

  A first embodiment of the present invention will be described with reference to FIG.

  A power generation system 1 according to the first embodiment shown in FIG. 1 includes a main generator 3 driven by a power source 2, a power conversion unit 5, and a controller 10, and the power conversion unit 5 supplies power from a DC power source 7. The main generator 3 is connected to the system 100 via the circuit breaker 61, and the power converter 5 is connected between the main generator 3 and the AC system 100 via the circuit breaker 62.

  In this embodiment, in the power generation system in which the power conversion unit 5 is deblocked during the startup of the power generation system for some reason, when the controller 10 starts up the power generation system 1, the circuit breaker 61 is first closed to After connecting the machine 3 and the AC system 100, the circuit breaker 62 is closed and the power conversion unit 5 is connected to the main generator 3.

  During startup of a power generation system in which the generator 3 is not connected to the AC system 100, a circuit breaker is provided and controlled so that a state where the switching power converter 5 is connected to the generator 3 does not occur. At the end, after the generator is connected to the AC system 100, the power converter 5 is connected to the main generator 3.

  The power supplied from the power conversion unit 5 is used for applications that absorb fast power fluctuations in the AC system 100 that cannot respond in time to the main generator 3 when the power generation system 1 transmits power to the system 100. May be.

  Whether the power source 2 is a water turbine, a rotating machine such as a single-shaft or multi-shaft gas turbine, or a reciprocating machine such as a diesel engine, the harmonics may affect the generator. For example, the same effects as those of the present embodiment described later can be obtained.

  The reason why the power conversion unit 5 is deblocked during the start-up of the power generation system is based on the assumption that power is mainly supplied to the starter 4 for starting the power source, but is not limited thereto.

  When the power source 2 is a power source that requires the starter 4 such as a gas turbine or a water turbine, the power converter 5 is deblocked to supply power to drive the starter during the start-up of the power generation system, and the same Use of the power conversion unit 5 during normal operation is advantageous in terms of cost.

  The main generator 3 is preferably a synchronous generator, but is not limited thereto.

  The DC power source 7 for supplying power to the power converter 5 may be a DC power source such as a storage battery or a buffer for a capacitor, or a power source composed of another generator and a transformer / rectifier. As described above, it may be electric power supplied from a rotating machine coaxial with the compressor, or a combination thereof.

  The power converter 5 generates harmonic current due to switching, whether it is a current-type or voltage-type single-phase to multi-phase inverter using IGBT, thyristor or MOSFET, or a multi-level or multi-level inverter. The same effect as this embodiment can be obtained.

  In the present embodiment, the inverter may be used as a rectifier in reverse, and even if described / signed as an inverter, its power conversion function is not limited to conversion from direct current to alternating current. Also, depending on the combination of inverters, it can also be an AC / AC converter such as a step-down transformer, and other power conversion means can be substituted, so the means for converting these powers is collectively referred to as a power conversion unit There is also.

  Each circuit breaker is a generic term for a device having a function of connecting or disconnecting a general electrical connection, which can be implemented by a switch, a switch, a certain protection circuit, or the like.

  As a method for starting the power generation system 1 having the above configuration, the present invention is characterized by the following procedure.

  The instruction destination from the controller 10 in FIG. 1 will be described later.

  As shown in the flowchart of FIG. 2, when the power generation system 1 is initially stopped, both the circuit breaker 61 and the circuit breaker 62 are open. First, the power source 2 is started and the rotational speed of the main generator 3 is increased. At that time, the power converter 5 is deblocked as necessary. After the main generator 3 reaches the rated speed, the circuit breaker 61 is closed and power transmission can be started. Thereafter, the circuit breaker 62 is closed, and the power converter 5 is connected to the main generator 3 and the system 100 line.

  In the power generation system 1 described above, when the above power generation system activation method is adopted, the following problems are solved, and the effect of improving the reliability and efficiency of the generator is obtained.

  The power converter 5 generates a harmonic current by switching or the like, and affects connected peripheral devices. When the circuit breaker 61 and the circuit breaker 62 are both closed during normal operation of the power generation system, the main generator 3 generally has an impedance 3 to 10 times that of the system, and harmonics from the power converter 5 Almost flows into system 100. However, when the power generation system is started, on standby, or stopped, the auxiliary power supply 555 having the power converter 5 is connected to the main generator 5 in a state where the main generator 3 is not connected to the system 100. Because most of the harmonics flow into the main generator 3, an electrical loss occurs in the main generator, and the harmonic component is included in the driving power of the generator, reducing the reliability of the generator There is.

When an inverter that generates a harmonic current is connected to a generator, a harmonic current is induced in the armature winding of the generator. Excess current flows, heat generation increases, and a heating phenomenon may occur, leading to an accident. Furthermore, vibrations may occur in the rotor due to harmonic components. These may reduce the reliability of the generator. In addition, since the harmonic becomes an antiphase component, it works in the direction of weakening the magnetic flux, and accordingly, the output of the generator is lowered and there is a possibility that the rotational speed increase speed of the generator is lowered.

  In the second embodiment, a power generation system that uses the rotational energy of a two-shaft gas turbine as an auxiliary power source is supplied to the power converter 5 by supplying power generated by a motor connected to the compressor by a shaft. The method is shown.

  The power generation system 1 as a whole is configured to cope with power fluctuations due to renewable energy and the like, and large power is output from the main generator 3 and small and steep fluctuation power is output from an auxiliary power source including the motor 4 and the inverter 5.

  In the power generation system of the present embodiment, which has the advantage that an expensive storage battery need not be provided in the power conversion unit 5 connected in parallel with the generator 3 in order to cope with the voltage fluctuation of the AC system 100, the motor 4 is gas When used together as a turbine starter, there is a problem that harmonics enter the generator 3 when the power generation system is started.

  In the configuration of the present embodiment, the phenomenon that the AC system works as a ground for the harmonics generated by the voltage converter normally can be used in a simple start-up sequence efficiently even at the start-up of the power generation system, and shut off at the start-up. By devising the control for opening and closing the generator, it is possible to obtain the effect of suppressing the harmonic inflow to the generator 3.

  Since the gas turbine power generation system generally has a shorter start-up time than the steam turbine power generation system, it is expected to contribute to the stabilization of the system when introducing renewable energy by short-time start-up.

  A gas turbine power generation system includes a single-shaft gas turbine power generation system in which a compressor, a turbine, and a generator are mechanically connected to one shaft. The second turbine is provided on a first turbine and a second shaft that is not mechanically connected to the first turbine shaft, and the second turbine is rotated by exhaust of the first turbine, whereby the second turbine is rotated. There is a two-shaft gas turbine power generation system that generates electric power by rotating a rotor of a generator mechanically connected to a second turbine shaft. A twin-shaft gas turbine has the advantage of being compact and capable of generating high output.

  First, the two-shaft gas turbine 2 will be described with reference to FIG. The gas turbine 2 mainly includes a compressor 20 that compresses air, a combustor 21 that mixes and burns fuel supplied from a fuel tank (not shown) and compressed air supplied from the compressor 20, and exhaust expansion of the combustor 21 The high-pressure turbine 22 that rotates by receiving force, the low-pressure turbine 23 that receives exhaust from the turbine 22 and obtains rotational torque, and mechanically connects the compressor 20 and the high-pressure turbine 22 to increase the rotational torque of the compressor 20 A rotary shaft 24 that transmits to the side turbine 22 and a rotary shaft 25 that is connected to the low-pressure turbine 23 and transmits the rotational torque to the rotor of the generator 3 are configured.

  Further, the compressor 20 of the gas turbine 2 may be provided with an inlet guide vane (hereinafter referred to as IGV) 26 for adjusting the air flow rate sucked by the compressor, and a fuel injection amount adjusting valve 27 for the combustor 21. .

  The fuel is supplied to the combustor 21 through the pipes 270 and 271. In addition, the air compressed by the compressor 20 is supplied to the combustor 21 through the pipe 201. Exhaust gas from the combustor 21 is supplied to the high-pressure turbine 22 through the pipe 210.

  FIG. 4 shows the configuration of the second embodiment of the present invention.

  The inverter 5 is a device that drives the motor 4.

  In order to reduce current harmonics generated from the inverter 5, a harmonic filter 85 may be used.

  Further, in order to increase the degree of freedom in selecting the IGBT, the voltage is converted by the transformer 82 to match the voltages of the inverter 51 and the main generator 3, and the circuit breaker 62 is placed on the system side.

  Further, in order to match the voltages of the system 100 and the main generator 3, a transformer 83 is placed on the generator side of the circuit breaker 61.

  The main generator 3 rotates coaxially with the low-pressure turbine 23 and maintains constant rotation to stabilize the system frequency. On the other hand, the compressor 20, the high-pressure turbine 22 and the motor 4 are connected to the rotary shaft 24, but it is not always necessary to perform constant rotation. Therefore, if the speed of the rotating shaft 24 is made variable, the rotational energy can be converted into electric power using the motor 4 and the inverter 5 on the flywheel principle, and input / output to / from the system. This can be regarded as an auxiliary power source composed of the power converter 5 and the DC power source 7 in the first embodiment. In other words, the output from the generator cannot be changed suddenly in response to a steep output fluctuation request, but an auxiliary power supply is added by inputting / outputting the rotational energy on the compressor side with more freedom in rotational speed. A power generation system corresponding to the above can be provided.

  The rotation speed N_HPC on the compressor side is measured by the rotation speed sensor 70. This inverter 5 has a configuration in which two inverters 5A and 5B are connected by DC terminals and a capacitor is provided between them so that electric power can be sent in both directions. Each of 5A and 5B, which will be described later, adopts the configuration shown in FIGS. 6 and 7, for example.

  In order to supply electric power to the motor 4 at the time of starting, a generator 92 is connected via a rectifier 91 to a direct current portion between 5A and 5B.

As shown in FIG. 4, the input signals to the controller 10 are the power load command MWD, the output P_GEN and the rotational speed N_GEN of the main generator 3, and the motor output P_GEN and the rotational speed N_HPC of the high-pressure shaft 24. As for the output of the controller 10, the gas turbine 2 sends the fuel command Fuel_CMD and the IGV opening command IGV_CMD, and the motor 4 sends the torque command Tq_CMD so that the sum of the generator output P_GEN and the motor output P_MOT matches the output command. .
Here, the starting method of this electric power generation system which is the 2nd Example of this invention is demonstrated using FIG. First, the generator 92 is activated with the circuit breaker 62 not turned on and not connected. The voltage is converted into a direct current by the rectifier 91, and a voltage is applied to the direct current circuit between the inverters 5A and 5B. Next, the inverter 5B is deblocked, the motor 4 is driven, and the rotation speed of the compressor 20 is increased. When the compressor 20 reaches a certain number of rotations, combustion is started in the combustor 21 and gradually increased until the rated rotation is reached. When combustion starts, the low-pressure turbine 23 starts rotating. Although the inverter 5A remains blocked, the harmonic current of the inverter 5B is also applied to the transformer 82. However, no loss occurs in the main generator 3 because it is disconnected by the circuit breaker 62. After that, when the gas turbine can be operated independently by the same procedure as in the first embodiment, the power from the generator 92 is stopped, and the motor 4 stops working. When the rotational speed is gradually increased and the low-pressure turbine 23 reaches the synchronous speed, the main generator 3 is controlled synchronously and is supplied to the system 100 by the circuit breaker 61 so that normal power generation becomes possible. Finally, the circuit breaker 62 is turned on to cooperatively control both the motor 4 and the main generator 3. The feature of the present embodiment is that the circuit breaker 62 is turned on after the circuit breaker 61 is turned on, so that the harmonic current caused by the inverter 5B that is starting the power generation system flows into the main generator 3. Can be prevented. In this embodiment, the inverter is used for startup for a long time, and it is possible to effectively suppress the harmonic loss of the generator from when deblocking of the initial inverter 5B is started to when the breaker 62 is turned on. .

  As shown in FIG. 6, the connection place of the generator 92 that supplies power for driving the motor 4 may be between the inverter 5 </ b> A and the circuit breaker 62. Further, the connection place may be between the inverter 5B and the motor 4.

  The generator 92 is an AC generator and is connected in parallel between the transformer 82 and the inverter via the circuit breaker 64. In this method, the AC power of the emergency generator 92 is converted to DC by the inverter 5A, and the motor 41 is driven by the inverter 5B.

In the configuration of FIG. 6 as well, as in the first and second embodiments, the gas turbine is started with the circuit breaker 62 opened, and after the gas turbine normally generates power, the circuit breaker 62 is turned on and the motor 41 and Start coordinated control of generator 3. With this control method, the harmonic current flowing from the inverter 5 into the main generator 3 during startup can be eliminated.

  FIG. 7 shows a configuration diagram of the gas turbine power generation system 1 of the present embodiment. In this embodiment, electric power for driving the motor 4 at the time of starting the gas turbine is supplied from the AC system 100. For this purpose, in this embodiment, switching means for freely switching the connection relationship between the power converter 5, the generator 3, and the AC system 100 is provided in a form including the circuit breaker 61 and the circuit breaker 62.

  The configuration of this embodiment is effective in that it is not necessary to install a separate generator in order to secure electric power for driving the motor 4.

  In the power generation system 1 of FIG. 7, the description of the components having the same reference numerals as those described in the first and second embodiments and the parts having the same functions is omitted.

  In the power generation system of FIG. 7, the power conversion unit 5 is connected to both the generator 3 side and the AC system 100 side of the circuit breaker 61, and switching means for switching the connection state by connecting or disconnecting these two connections. Is provided.

  The starting method of the power generation system 1 of FIG. 7 is shown in FIG. 8 and is as follows. Initially, the power source 2, the generator 3, and the inverter 5 are stopped, and all circuit breakers are opened. After closing the circuit breaker 65, the power converter 5 is deblocked, and the motor 4 is driven to increase the rotational speed of the compressor. After confirming the gas turbine ignition, the circuit breaker 65 is opened to stop the driving of the motor 4, the circuit breaker 61 is closed after the generator 3 is synchronized with the system at a predetermined number of revolutions, and then the circuit breaker 62 is closed.

  The switching means in this embodiment can also be implemented by connection as shown in FIG. In the power generation system of FIG. 9, there are two circuit breakers of a circuit breaker 61 and a circuit breaker 66 between the generator 3 and the AC system 100, and the power conversion unit 5 is connected to the circuit breaker 61 and the circuit breaker via the circuit breaker 62. It has the structure connected between 66.

  Although the sequence and combination of closing the circuit breakers are different, the specific control procedure is explained because the connection relationship between the inverter 5, the generator 3, and the AC system 100 can be made the same as in the power generation system 1 of FIG. Omitted.

The switching means in the present embodiment may have any other form as long as it has a function of appropriately switching the connection relationship between the inverter 5, the generator 3, and the AC system 100.

  In the third embodiment, switching means is provided to supply electric power for driving the motor 4 from the AC system 100. However, in this embodiment, the motor 4 is connected to the starting motor 42 and the rotating shaft as shown in FIG. The starter motor 42 can be divided into the motor 41 that inputs and outputs energy, and can also be implemented by connecting to the AC system 100 via the step-down transformer 81 and the circuit breaker 63. Further, as shown in FIG. 11, another generator 92 may be provided to supply power to the starter motor 41.

  In the power generation system 1 of FIG. 10, the description of the components having the same reference numerals as those described in the first, second, and third embodiments and the parts having the same functions are omitted.

  The storage battery 7 may be provided in the direct current section between the inverter 5A and the inverter 5B. In that case, the inverter 5B may be deblocked when the power generation system 1 is started, and the power of the storage battery 7 may be used to drive the motor 41. Conversely, the power generated by the motor 41 may be used as the storage battery 7 or the direct current. It may be stored in the capacitor of the part in preparation for the output fluctuation of the AC system 100.

The contents of control performed by the controller 10 in the present embodiment are the same as those in the third embodiment except for the devices added as described above. Replacement and conforms to the contents of the flowchart of the third embodiment.

  The block diagram of the gas turbine power generation system 1 of the 5th Example of this invention is shown in FIG.

  In the power generation system 1 of FIG. 12, the description of the components having the same functions as those already described in the first, second, third, and fourth embodiments and the parts having the same functions are omitted. .

  The gas turbine power generation system 1 is mainly composed of a gas turbine 2 as a power source, a main generator 3 and a controller 10, and the gas turbine supplies power to the shaft, and the main generator converts the shaft input into electric power. The electric power generated by the main generator 3 is connected to the AC system 100 via the circuit breaker 61. As a feature of the present embodiment, the DC power source 7 is connected to the AC system 100 via the inverter 5 and the circuit breaker 62 in parallel with the main generator. This is a configuration to cope with power fluctuations due to renewable energy, etc., and the power generation system 1 as a whole outputs a large amount of power from the main generator 3, and a small and steep fluctuation power from the auxiliary power source consisting of the DC power source 7 and the inverter 5. To do.

  In the present embodiment, since the inverter 5 is directly connected only to the generator 3, more harmonic current may flow into the generator 3, which improves the efficiency and reliability of the generator 3. The effect is greater than in the other embodiments.

  The gas turbine 2 may be uniaxial or multi-axial.

  The phenomenon in which the AC system 100 works as a ground for the harmonics generated by the inverter 5 can be used efficiently and with a simple start-up sequence even when the power generation system 1 is started. As a result, the effect of suppressing the harmonic inflow to the generator 3 can be obtained.

  In this embodiment, since the motor 4 is used only for the purpose of rotating the compressor from the state where the rotational speed is zero, it is effective in that an expensive high-speed motor need not be employed.

  Examples of the DC power source 7 include a storage battery, a combination of a generator and a rectifier.

  A starter motor 4 connected to the shaft of the gas turbine 2 may be installed. In that case, the power source of the starter motor 4 may be obtained from a system in the system, may be obtained from a power source prepared separately in the system, or a transformer 81 and a circuit breaker 63 as shown in FIG. It may be obtained from the system 100 via

  Next, an example of the configuration of the inverter 5 will be described with reference to FIG.

  The inverter 5 of this embodiment is a two-level inverter composed of three arms in which two IGBT elements are connected in series.

  The IGBT elements 5m to 5r are composed of an IGBT and a diode connected in reverse parallel to the IGBT. The gate signal GateSig output from the controller 10 is input to the gate which is the control electrode of the IGBT elements 5m to 5r, and the IGBT is on / off controlled.

  The inverter 5 outputs an alternating voltage containing harmonic components to the terminals U, V, and W by adjusting the on / off time ratio of the IGBT element.

  Reactor 5fil is provided to suppress harmonic current generated by the voltage harmonic.

  A DC power supply 7 is connected to the terminals P and N. The DC power supply 7 supplies DC power to the inverter 5 or supplies a constant DC voltage by charging the DC power.

  As shown in FIG. 14, the inverter 5 may be connected to the main generator 3 and the AC system 100 via the transformer 5tr, so that a harmonic filter can be obtained with a harmonic reduction effect due to leakage inductance. Furthermore, by using the transformer 5tr, it becomes possible to select an IGBT having an appropriate voltage / current specification regardless of the voltage of the AC system 100, so that the effect of increasing the degree of design freedom can be obtained.

  The inverter 5 can achieve the same effect even with a multi-level inverter represented by a three-level inverter as shown in FIG.

  FIG. 15 shows the startup state of such a gas turbine power generation system. First, the circuit breaker 63 is turned on, and the starting motor 4 is driven. As a result, the rotational speed of the gas turbine 2 increases. When it reaches a certain speed, fuel is injected into the gas turbine 2 and combustion starts, and the rotational speed is increased by both the output of the gas turbine itself and the motor power. When the gas turbine 2 can rotate independently, the motor power is disconnected by the circuit breaker 63, and the rotation speed is increased while increasing the output of the gas turbine. When the rotational speed reaches the rated rotational speed, control is performed to synchronize the AC voltage and phase of the main generator 3 and the system 100 next. When this synchronization is completed, the circuit breaker 61 is turned on and power generation can be started. After that, the circuit breaker 62 is turned on, and the inverter 5 is connected to the system.

Before the circuit breaker 62 is turned on, the output voltage of the inverter 5 needs to be synchronized with the system 100 voltage as well as the synchronous control of the main generator 3. Therefore, switching of the inverter 5 is started (deblocked) in advance. At this time, even if the output command of the inverter 5 is set to zero, if the main generator 3 is not disconnected by the circuit breaker 62, harmonic current caused by switching flows through the main generator 3. This harmonic current has a problem of causing a flow loss in the stator winding of the main generator 3. However, if the circuit breaker 62 is used for cutting, there is no loss in the main generator 3. In this embodiment, the circuit breaker 62 is turned on after the circuit breaker 61 is turned on. This is because the harmonic current of the inverter 5 mainly flows to the system 100 side after the circuit breaker 61 is turned on. When viewed from the inverter, the system 100 side and the main generator 3 side are parallel, and a current flows through the parallel circuit in inverse proportion to the impedance. Generally, the impedance of the system is sufficiently smaller than the impedance of the generator, so that the harmonic current hardly flows into the main generator 3 after the circuit breaker 61 is turned on. For this reason, the circuit breaker 62 may be placed after the circuit breaker 61 is turned on.

  The present embodiment relates to control when the power generation system 1 is stopped or when power transmission to the AC system 100 is interrupted. This will be described with reference to FIG.

  When stopping the power generation system or interrupting power transmission to the AC system 100, the circuit breaker 61 is opened to disconnect the power generation system 1 from the AC system 100. At that time, the power conversion unit 5 is in operation. If the circuit breaker 62 is closed, the harmonic current generated in the power converter 5 may flow into the generator 3 in large quantities, and the problem of reducing the reliability of the generator is the same as when the power generation system is started. It is in.

  By adopting the control sequence of the power generation system 1 that opens the circuit breaker 61 after opening the circuit breaker 62, the harmonics from the power converter 5 are prevented from flowing into the generator 3, and the efficiency of the generator There is an effect of improving reliability.

  As a situation where the power generation system 1 is disconnected from the AC system 100, for example, a situation where some kind of failure has occurred on the AC system or the power generation system side can be considered.

  The sequence for separating the power generation system 1 and the AC system 100 in this embodiment can be implemented by a power generation system having the structure described in the first to fifth embodiments. In addition, since the situation where the power converter 5 is activated in the present embodiment is assumed at the start stage of the sequence to be disconnected, the situation where the power converter 5 that was present at the start of the power generation system 1 is moved is, for example, the starter 4 or the like Configuration requirements are not mandatory.

For example, when implemented in the power generation system of FIG. 1, the control content of the controller 10 in this embodiment is as shown in FIG. The generator 3 is disconnected from the AC system 100 by first opening the circuit breaker 62 and then opening the circuit breaker 61.

DESCRIPTION OF SYMBOLS 1 Power generation system 2 Gas turbine 3 Generator 4 Motor 5 Power conversion part 9 Generator 20 Compressor 21 Combustor 22 High pressure turbine 23 Low pressure turbine 24 High pressure shaft 25 Low pressure shaft 61, 62, 63, 64, 65, 66 Breaker 81 82 transformers

Claims (15)

A power source, a generator driven by the power source, and a power conversion unit, the generator and the power conversion unit are connected to the AC system in parallel;
Has a first circuit breaker provided between the AC system and the generator,
The power converter is connected to the AC system via the first circuit breaker,
A second circuit breaker provided between the first circuit breaker and the power converter;
A power generation system including a controller that controls opening and closing of the deblocking of the power conversion unit, the first circuit breaker, and the second circuit breaker;
When the controller outputs a deblocking command for the power converter in a state where the first circuit breaker and the second circuit breaker are open, after the controller issues a closing command for the first circuit breaker A power generation system configured to issue a closing command for the second circuit breaker. The power generation system according to claim 1,
The controller is configured to issue a closing command for the second circuit breaker after confirming that the first circuit breaker is closed. A power source, a generator driven by the power source, and a power conversion unit, the generator and the power conversion unit are connected to the AC system in parallel;
Has a first circuit breaker provided between the AC system and the generator,
The power converter is connected to the AC system via the first circuit breaker,
A second circuit breaker provided between the first circuit breaker and the power converter;
A power generation system including a controller that controls opening and closing of the deblocking of the power conversion unit, the first circuit breaker, and the second circuit breaker;
Wherein the controller, when the power conversion unit in a state where the first circuit breaker and said second circuit breaker are closed is operating, after said issuing an open command of the second circuit breaker first A power generation system configured to issue a command to open a circuit breaker. The power generation system according to claim 3,
The controller is configured to issue an opening command for the first circuit breaker after confirming that the second circuit breaker is opened. The power generation system according to any one of claims 1 to 4,
The power source comprises a starter;
The power converter is
A first power converter connected via the generator and the second circuit breaker;
A second power converter connected to the starter;
A power generation system comprising a capacitor provided between the first power conversion unit and the second power conversion unit . The power generation system according to any one of claims 1 to 5,
The power source comprises a starter;
A power generation system comprising a power source for supplying power to the starter. The power generation system according to claim 6, wherein
When the controller outputs a deblocking command for the power conversion unit in a state where the first circuit breaker and the second circuit breaker are open, the power source supplies power to a starter to power the power source. The power generation system is configured to issue a closing command for the first circuit breaker after starting, and then issue a closing command for the second circuit breaker. The power generation system according to any one of claims 1 to 5,
The power source comprises a starter;
A power generation system configured to supply power from the AC system to the starter in a state in which the generator is disconnected from the AC system. The power generation system according to claim 8, wherein
A switching system that connects the AC system side of the first circuit breaker and the power conversion unit side of the second circuit breaker, and a third circuit breaker provided on the switching system,
The controller supplies power from the AC system via the closed third circuit breaker while the first circuit breaker and the second circuit breaker are open, and the power converter is connected to the power converter. A power generation system characterized by blocking. The power generation system according to claim 8, wherein
A third circuit breaker is provided between the first circuit breaker and the generator, and between the second circuit breaker and the generator, and the controller includes the first to third circuit breakers. If There the and the power conversion unit in a state open all set to start a state where no deblocking, the first and closing command of the second circuit breaker, deblocking command of the power conversion unit, the second The power generation system is configured to issue a command in the order of a circuit breaker open command, a third circuit breaker close command, and a second circuit breaker close command. The power generation system according to any one of claims 1 to 10,
A power generation system, wherein a transformer is provided between the generator and the power converter . The power generation system according to any one of claims 1 to 11,
A power generation system, wherein a harmonic filter is provided between the generator and the power conversion unit . The power generation system according to any one of claims 1 to 12,
The power source is
A compressor for compressing air;
A combustor that mixes and combusts air and fuel compressed by the compressor;
It is a gas turbine provided with the turbine which obtains rotational force with the exhaust gas of the said combustor, The power generation system characterized by the above-mentioned. The power generation system of claim 13,
The power generation system, wherein the gas turbine is a two-shaft gas turbine. A power source, a generator driven by the power source, and a power conversion unit, the generator and the power conversion unit are connected to the AC system in parallel;
Has a first circuit breaker provided between the AC system and the generator,
The power converter is connected to the AC system via the first circuit breaker,
A control method for a power generation system including a second circuit breaker provided between the first circuit breaker and the power conversion unit,
A power generation system comprising: starting the power conversion unit with the first and second circuit breakers open; then closing the first circuit breaker; and then closing the second circuit breaker. Control method.

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