JP2010088234A - Exciting arrangement of power generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exciting arrangement of a power generator which eliminates the need for complicated control at the time of starting and allows simplification. <P>SOLUTION: When starting the power generator 1, an isolator 12 and a field circuit breaker 6 are closed and an exciting current is supplied to a field winding 1a of the power generator 1 from a DC power supply line 9. At that time, the output of the power generator 1 is low and a thyristor rectifier 5 is not gate controlled and is in an open state. When a voltage VG rises with a rotation rise of the power generator 1 and reaches a prescribed voltage V1, gate control over the thyristor rectifier 5 is started and exciting current supply is started from a power generator 1, and the isolator 12 is opened. When the voltage VG of the power generator 1 reaches V1, a resistance value of the resistor 11 is set so that the exciting current is supplied from the power generator 1 but not supplied from the DC power supply line 9 and the current flowing in the isolator 12 becomes almost zero. Since a supply source of the exciting current is switched from the DC power supply line 9 to the power generator 1 when the current flowing in the isolator 12 becomes almost zero, complicated control is unnecessary at the time of starting. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a generator excitation device.

  Conventionally, in a gas turbine static start system as an exciter for a generator, when the gas turbine is started, the variable frequency voltage from the static start device is directly connected to the gas turbine via an inverter transformer and a start disconnector. Applied to the synchronized generator. An excitation current is supplied from the starting excitation power source to the field winding of the generator. The starting excitation power source includes a circuit breaker connected to an AC local power source, a starting excitation power transformer, a starting excitation rectifier, and a starting circuit breaker. On the other hand, after the start of the gas turbine is completed, the starting circuit breaker is opened, the in-house power supply is disconnected, the switching disconnector is closed, and the DC voltage of the forward converter is applied to the field winding of the synchronous generator, An exciting current is supplied from the forward converter (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 7-332012 (paragraph numbers 0036 and 0037 and FIG. 1)

  A conventional gas turbine stationary start system as an exciter for a generator is configured as described above, and an excitation current is supplied from the start excitation power source to the field winding of the generator via the start breaker at the start. After the start-up is completed, the start-up circuit breaker is opened and the switching disconnector is closed, the DC voltage of the forward converter is applied to the field winding of the synchronous generator, and the exciting current is supplied from the forward converter. The For this reason, after starting, the starting circuit breaker is opened to disconnect the synchronous generator field winding from the starting exciting power source, and the switching disconnector is closed to the synchronous generator field winding. A voltage must be applied. Therefore, switching control between the starting circuit breaker and the switching disconnector is necessary. At the same time, it is necessary to control the forward converter appropriately, and complicated control including switching control is required, which complicates the device, and further requires a starting circuit breaker. There was a problem of becoming complicated.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a generator excitation device that does not require complicated control at the time of startup and can simplify the device.

In the generator excitation device according to the present invention,
Having first and second excitation devices for supplying excitation current to the field winding of the generator,
The first excitation device has a DC converter and field opening / closing means,
The DC converter converts the generator AC output to the generator DC output, and the generator DC output is supplied to the field winding via the field switching means.
The second excitation device has a startup excitation current output device, a switch, and a switch control device.
The start-up excitation current output device outputs a start-up excitation current, and is connected to the DC conversion device side of the field switching means via a switch and connected to the field winding via the field switching means. Connected to the wire
The switch control device closes the switch when the generator is started, supplies the start-up excitation current to the field winding from the start-up excitation current output device, and supplies the generator-side DC output from the first excitation device. Supplied in a state where it can be supplied to the magnetic winding, and when the output voltage of the generator is detected to be a predetermined voltage or the output voltage of the generator rises and is supplied to the field winding from the excitation current output device at the start When the starting excitation current is detected to be almost zero, the switch is opened, and the generator side DC output is supplied to the field winding from the first excitation device.

This invention
Having first and second excitation devices for supplying excitation current to the field winding of the generator,
The first excitation device has a DC converter and field opening / closing means,
The DC converter converts the generator AC output to the generator DC output, and the generator DC output is supplied to the field winding via the field switching means.
The second excitation device has a startup excitation current output device, a switch, and a switch control device.
The start-up excitation current output device outputs a start-up excitation current, and is connected to the DC conversion device side of the field switching means via a switch and connected to the field winding via the field switching means. Connected to the wire
The switch control device closes the switch when the generator is started, supplies the start-up excitation current to the field winding from the start-up excitation current output device, and supplies the generator-side DC output from the first excitation device. Supplied in a state where it can be supplied to the magnetic winding, and when the output voltage of the generator is detected to be a predetermined voltage or the output voltage of the generator rises and is supplied to the field winding from the excitation current output device at the start When the start-up excitation current is detected to be almost zero, the switch is opened, and the generator side DC output is supplied to the field winding from the first excitation device.
It is possible to obtain a generator excitation device that does not require complicated control at the time of startup and can simplify the device.

Embodiment 1 FIG.
1 and 2 show Embodiment 1 for carrying out the present invention. FIG. 1 is a block diagram showing the configuration of a generator excitation device, and FIG. 2 shows the operation of the control device of FIG. It is explanatory drawing for demonstrating. In FIG. 1, a generator 1 driven by a gas turbine has a field winding 1a, and an armature winding (not shown) is connected to the power system. Further, the exciting transformer 2 is connected to the generator 1, and the alternating current of the stepped-down generator 1 is converted into direct current by the thyristor rectifier 5 so that it can be supplied to the field winding 1 a via the field breaker 6. Has been.

  A DC power supply line 9 connected to a DC power supply (not shown), a backflow prevention diode 10, a resistor 11 for setting a current value to an appropriate excitation current, and a disconnector 12 are connected to the DC output side of the thyristor rectifier 5. It is connected. The disconnector 12 is for disconnecting this circuit when the DC power supplied from the outside necessary at the time of startup becomes unnecessary. The output voltage of the generator 1 is detected by the instrument transformer 41 and sent to the control device 16. The control signal of the control device 16 is output to the disconnector 12 and the thyristor rectifier 5.

  The excitation transformer 2, the thyristor rectifier 5 as a DC converter, and the field breaker 6 as a field switching means are the first excitation devices in the present invention, and a DC power source as an excitation current output device at start-up. The line 9, the resistor 11, the disconnector 12 as a switch, and the control device 16 as a switch control device are the second excitation device in the present invention.

Next, the operation will be described.
In FIG. 1, when the generator 1 is started, the disconnector 12 and the field breaker 6 are closed, and excitation current is supplied to the field winding 1 a of the generator 1 by power supply from the DC power supply line 9 side. The At this time, the output of the generator 1 is low, so the field voltage via the excitation transformer 2 is low, the thyristor rectifier 5 is not gated, and is open. Therefore, the DC power source 9 side and the excitation transformer 2 side are in an insulated state. As the rotation of the generator 1 increases, the voltage VG increases with the passage of time t as shown in FIG.

  At time t1, the voltage VG of the generator 1 reaches a predetermined voltage V1, that is, the voltage on the secondary side of the excitation transformer 2 reaches a voltage necessary for supplying an excitation current to the field winding 1a. The output voltage of the generator 1 is monitored by the control device 16 via the instrument transformer 41. When the voltage VG of the generator 1 reaches the voltage V1, the control device 16 starts the gate control of the thyristor rectifier 5. Then, the supply of the excitation current from the excitation transformer 2 side is started and the disconnector 12 is opened. When the voltage VG of the generator 1 reaches the voltage V1, the field winding 1a is supplied with exciting current from the exciting transformer 2 and thyristor rectifier 5 side, and is not supplied from the DC power supply line 9 side and is disconnected. The resistance value of the resistor 11 is set so that the current flowing through the resistor 12 becomes substantially zero.

  As described above, according to this embodiment, at the time of start-up, excitation current is supplied from the DC power supply line 9 side so that the voltage VG of the generator 1 reaches the predetermined voltage V1 and the excitation current can be supplied from the generator 1. When the current flowing through the disconnector 12 becomes almost zero, the disconnector 12 is opened to disconnect the DC power supply line 9 side from the field winding 1a. For this reason, complicated control is not required. Further, it is not necessary to provide a circuit breaker for interrupting the current supplied to the field winding 1a on the DC power supply line 9 side for switching, and it is sufficient to provide the disconnecting switch 12, and a complicated control logic is required. Not. For this reason, the excitation device of the generator can be simplified.

Embodiment 2. FIG.
FIG. 3 is a configuration diagram showing the configuration of the generator excitation device according to Embodiment 2 of the present invention. In FIG. 3, the resistance value of the field winding 1 a of the generator 1 does not necessarily match the designed value, and the resistance value may change due to rewinding work of the field winding 1 a or the like. In that case, it is necessary to adjust the current supplied to the field winding 1a at the start-up to an appropriate value according to the resistance value of the field winding 1a. This embodiment is for coping with the above-mentioned problems, and by making the variable resistor 13 a resistor with a tap or a slider, the resistance value can be easily adjusted during an adjustment test or the like. It is possible to set an appropriate excitation current.
The DC power supply line 9, the variable resistor 13, the disconnector 12, and the control device 16 are the second excitation device in the present invention.

Embodiment 3 FIG.
FIG. 4 is a configuration diagram showing the configuration of the generator excitation device according to Embodiment 3 of the present invention. In FIG. 4, the resistance of the field winding 1a of the generator 1 varies depending on the temperature of the field winding 1a. Therefore, an appropriate resistance value of the variable resistor 13 varies depending on the temperature of the field winding 1a. In this embodiment, a temperature measuring element 31 for measuring the temperature of the field winding 1a of the generator 1 is provided, the variable resistance 33 is adjusted by the resistance control device 36 according to the detected temperature, and an appropriate excitation current is allowed to flow. It is made to be able to.
The DC power supply line 9, the variable resistor 13, the disconnector 12, and the control device 16 are the second excitation device in the present invention.

  According to this embodiment, the exciting current supplied from the DC power supply line 9 side can be controlled to an appropriate current value, and the capacity of the DC power supply can be made appropriate without being excessive.

Embodiment 4 FIG.
FIG. 5 is a configuration diagram showing the configuration of the generator excitation device according to Embodiment 4 of the present invention. In FIG. 5, in each of the embodiments described above, a resistor is used to adjust the excitation current supplied from the DC power supply line 9 side at the time of startup, so that the excitation current value required at the time of startup is small. In this case, there is no problem. However, when the generator has a large capacity and the excitation current increases, the heat generation increases, so that there is a problem that the size of the resistor increases and the power loss also increases.

This embodiment is for solving such a problem. The voltage Vac of the AC power supply line 15 connected to an AC power supply (not shown) is reduced to a voltage for supplying an appropriate excitation current by the transformer 18. The voltage is stepped down, and the exciting current is supplied to the field winding 1 a of the generator 1 by the diode rectifier 17.
The AC power line 15, the transformer 18, the diode rectifier 17, the disconnector 12, and the control device 16 serving as a startup DC converter are the second excitation devices in the present invention.

  According to this embodiment, since the power loss is mainly generated in the transformer 18 and the diode rectifier 17, the resistor 11 and the resistor 13 shown in FIGS. 1 and 3 are used. Compared with this, there is an effect that heat generation is reduced and the device size and power loss are reduced.

Embodiment 5 FIG.
FIG. 6 is a configuration diagram showing the configuration of the generator excitation device according to Embodiment 5 of the present invention. In FIG. 6, as described above, the resistance value of the field winding 1a of the generator 1 does not necessarily match the designed value, and may change due to rewinding work or the like. In addition, the value of the excitation current required at startup may not be as designed.

This embodiment is for coping with the above problems, and by using the transformer 19 with a tap changer, it becomes possible to adjust the transformer ratio of the transformer during the adjustment test. Instead of the transformer 19 with a tap changer, an electromagnetic induction device capable of changing the transformation ratio, such as a transformer with a load switching tap changer or an induction voltage regulator, can be used.
The AC power line 15, the transformer 19 with a tap changer as the output voltage variable transformer, the diode rectifier 17, the disconnector 12, and the control device 16 as the start-up DC converter are the second excitation device in the present invention. It is.

Embodiment 6 FIG.
FIG. 7 is a block diagram showing the configuration of the generator excitation device according to Embodiment 6 of the present invention. In FIG. 7, as described above, the value of the excitation current required at the time of startup varies depending on the resistance value of the field winding 1a, and the resistance of the field winding varies depending on the temperature.

This embodiment is for coping with the above-described problems. A temperature measuring element 31 for measuring the winding temperature of the field winding 1a is provided, and a load is applied by the transformer control device 52 based on the detected temperature. The excitation current is adjusted by switching the transformation ratio of the transformer 51 with the hour tap changer.
In addition, the AC power line 15, the transformer 51 with a load tap changer as an output voltage variable transformer, the diode rectifier 17, the disconnector 12, the control device 16, and the transformer control device 52 as a DC converter for start-up. It is the 2nd exciting device in this invention.

  According to this embodiment, since the optimum excitation current can be supplied, the capacity of the AC power supply that supplies the excitation power at the time of startup can be made appropriate.

Embodiment 7 FIG.
FIG. 8 is a configuration diagram showing the configuration of the generator excitation device according to Embodiment 7 of the present invention. In Embodiments 5 and 6 (FIGS. 6 and 7), the excitation current supplied to the field winding 1a is adjusted by controlling the transformer 19 with a tap changer and the transformer 51 with a load tap changer. However, in FIG. 8, a thyristor rectifier 61 and a thyristor controller 62 are used.
The AC power line 15, the transformer 18, the DC converter for start-up, and the thyristor rectifier 61 and thyristor control device 62 as the start-up excitation current control device, the disconnector 12, and the control device 16 are the second excitation in the present invention. Device.

  According to this embodiment, the current supplied to the field winding 1a can be controlled by the thyristor controller 62 and the thyristor rectifier 61. Since the adjustment speed of the thyristor control device 62 and the thyristor rectifier 61 is sufficiently high compared with the current adjustment using the transformer with tap 19 or the transformer 51 with load tap changer, the controllability is more excellent. Current suppression is possible.

Embodiment 8 FIG.
FIG. 9 is a block diagram showing the configuration of the generator excitation device according to Embodiment 8 of the present invention. In the seventh embodiment, the thyristor rectifier is used. However, since the thyristor rectifier is used only to supply the excitation current at the time of start-up, the value of the excitation current to be passed is as small as about 1/10 in the steady operation. The IGBT rectifier 63 is provided, and the current supplied to the field winding 1a is adjusted by the IGBT control device 64. An IGBT (Insulated Gate Bipolar Transistor: Insulated Gate Bipolar Transistor) can be used in the same manner as a normal transistor, and does not require a complicated gate circuit as compared with a thyristor, and the control circuit is simplified correspondingly.
The AC power line 15, the transformer 18, the DC converter for start-up, and the IGBT rectifier 63 and IGBT control device 64 as the start-up excitation current control device, the disconnector 12, and the control device 16 are the second excitation in the present invention. Device.

  According to this embodiment, since the IGBT rectifier 63 and the IGBT control device 64 are used, the excitation current can be adjusted with a simpler control circuit than the thyristor rectifier, and the device can be configured at a lower cost.

Embodiment 9 FIG.
FIG. 10 is a configuration diagram showing the configuration of the generator excitation device according to Embodiment 9 of the present invention. In the fifth and sixth embodiments, the tap transformer 19 for stepping down the AC power supply Vac and the transformer 51 with load tap changer are provided to step down the voltage and adjust the voltage. In this embodiment, As shown in FIG. 10, the thyristor rectifier 65 having a high withstand voltage is controlled by the thyristor control device 66, so that the tapped transformer 19 and the on-load tap changer-equipped transformer 51 are not required.
The AC power line 15, the thyristor rectifier 65 and the thyristor controller 65, the disconnector 12, and the controller 16 as the startup DC converter and the startup excitation current controller are the second excitation devices in the present invention.

  According to this embodiment, the tapped transformer 18 and the on-load tap changer-equipped transformer 19 can be omitted, and the apparatus can be configured at lower cost.

Embodiment 10 FIG.
FIG. 11 is a configuration diagram showing the configuration of the generator excitation device according to Embodiment 10 of the present invention. In the ninth embodiment (FIG. 10), the thyristor rectifier 65 having a high breakdown voltage is provided to adjust the voltage. In this embodiment, as shown in FIG. 11, the IGBT rectifier 71 having a high breakdown voltage is IGBT-controlled. By controlling with the apparatus 72, the transformer 18 with a tap and the transformer 19 with a load tap changer are abbreviate | omitted.
Note that the AC power line 15, the startup DC converter, and the IGBT rectifier 71 and IGBT control device 72, the disconnector 12, and the control device 16 as the startup excitation current control device are the second excitation device in the present invention.

  According to this embodiment, since the IGBT that can simplify the control circuit from the thyristor rectifier is used, the apparatus can be configured at a lower cost.

Embodiment 11 FIG.
FIG. 12 is a block diagram showing the configuration of the generator excitation device according to Embodiment 11 of the present invention. In the above first to tenth embodiments, the instrument transformer 41 and the control device 16 detect that the output voltage VG of the generator 1 becomes the predetermined value V1. At this time, the current flowing through the disconnector 12 is set to almost zero. In this embodiment, instead of detecting that the output voltage VG of the generator 1 becomes a predetermined value V1, a DCCT (DC current transformer) 75 is provided between the disconnector 12 and the field breaker 6. The controller 76 detects that the current flowing through the DCCT 75 becomes almost zero, starts the gate control of the thyristor rectifier 5 and starts supplying the exciting current from the exciting transformer 2 side, and disconnects the disconnector 12. Open.

  According to this embodiment, it is detected that the current flowing through the disconnector 12 becomes almost zero and the source of excitation current is switched from the DC power supply line 9 side to the excitation transformer 2 (generator 1) side. Therefore, switching can be performed at a more accurate timing. In the second to eleventh embodiments, instead of the control device 16, the same DCCT 75 and control device 76 detect the timing at which the excitation current flowing from the DC power supply line 15 side to the excitation winding 1a becomes almost zero. Also good.

Embodiment 12 FIG.
FIG. 13 is a configuration diagram showing the configuration of the generator excitation device according to Embodiment 12 of the present invention. In the above first to eleventh embodiments, the thyristor rectifier 5 cannot be disconnected from the main circuit of the generator 1 because there is no circuit breaker on the AC side that is the generator 1 side of the thyristor rectifier 5. Although this is not a problem, in this embodiment, the AC side field breaker 22 is connected to the AC side of the thyristor rectifier 5 in order to disconnect the thyristor rectifier 5 from the main circuit of the generator 1 in the first embodiment of FIG. Is provided.

  According to this embodiment, as described above, since the thyristor rectifier 5 can be disconnected from the main circuit of the generator 1 when the AC side field breaker 22 is opened, the maintainability is excellent. In the second to eleventh embodiments, a similar AC side field breaker may be provided.

  In each of the above embodiments, the field breaker 6 is used, but a field disconnector can be used instead.

It is a block diagram which shows the structure of the excitation apparatus of the generator which is Embodiment 1 of this invention. It is explanatory drawing for demonstrating operation | movement of the control apparatus of FIG. It is a block diagram which shows the structure of the excitation apparatus of the generator which is Embodiment 2 of this invention. It is a block diagram which shows the structure of the excitation apparatus of the generator which is Embodiment 3 of this invention. It is a block diagram which shows the structure of the excitation apparatus of the generator which is Embodiment 4 of this invention. It is a block diagram which shows the structure of the excitation apparatus of the generator which is Embodiment 5 of this invention. It is a block diagram which shows the structure of the excitation apparatus of the generator which is Embodiment 6 of this invention. It is a block diagram which shows the structure of the excitation apparatus of the generator which is Embodiment 7 of this invention. It is a block diagram which shows the structure of the generator excitation apparatus which is Embodiment 8 of this invention. It is a block diagram which shows the structure of the exciting device of the generator which is Embodiment 9 of this invention. It is a block diagram which shows the structure of the excitation apparatus of the generator which is Embodiment 10 of this invention. It is a block diagram which shows the structure of the generator excitation apparatus which is Embodiment 11 of this invention. It is a block diagram which shows the structure of the generator excitation apparatus which is Embodiment 12 of this invention.

Explanation of symbols

1 generator, 1a field winding, 2 excitation transformer, 5 thyristor rectifier,
6 Field breaker, 9 DC power line, 10 Diode, 11 Resistor, 12 Disconnector,
13 variable resistor, 15 AC power line, 16 control device, 22 AC side field breaker,
33 variable resistor, 36 resistance control device, 17 diode rectifier, 18 transformer,
19 Transformer with tap, 41 Transformer for instrument, 51 Transformer with tap changer at load,
52 transformer control device, 61 thyristor rectifier, 62 thyristor control device,
63 IGBT rectifier, 64 IGBT controller, 65 thyristor rectifier,
66 thyristor control device, 71 IGBT rectifier, 72 IGBT control device,
75 DCCT, 76 controller.

Claims (10)

Having first and second excitation devices for supplying excitation current to the field winding of the generator,
The first excitation device has a DC converter and field opening / closing means,
The DC converter converts an AC output of the generator into a generator-side DC output, and the generator-side DC output is supplied to the field winding via the field switching means. And
The second excitation device includes a startup excitation current output device, a switch, and a switch control device.
The start-up excitation current output device outputs a start-up excitation current, and is connected to the DC conversion device side of the field opening / closing means via the switch to connect the field opening / closing means. Connected to the field winding via
The switch control device closes the switch when the generator is started, supplies the start-up excitation current from the start-up excitation current output device to the field winding, and from the first exciter. When the generator side DC output is ready to be supplied to the field winding, the generator output voltage is detected to become a predetermined voltage, or the generator output voltage rises to It detects that the starting excitation current supplied to the field winding from the exciting current output device becomes almost zero, opens the switch, and generates the generator side DC output from the first exciting device. A generator excitation device to be supplied to the field winding. 2. The start-up excitation current output device includes a resistor, and supplies the start-up excitation current to the field winding through the resistor. The generator excitation device described. 3. The generator excitation apparatus according to claim 2, wherein the resistor is a variable resistor capable of changing a resistance value. The generator according to claim 3, wherein the startup excitation current output device includes a resistance control device that controls a resistance value of the variable resistor in accordance with a temperature of the field winding. Exciting device. 2. The generator excitation according to claim 1, wherein the startup excitation current output device includes a startup DC converter that converts alternating current into direct current and outputs the startup excitation current. apparatus. The start-up excitation current output device has a transformer, and transforms the alternating current into an alternating current of a predetermined voltage by the transformer and supplies the alternating current to the start-up DC conversion device. The generator excitation device according to claim 5. The generator excitation device according to claim 6, wherein the transformer is an output voltage variable transformer capable of changing a transformation ratio. 8. The startup excitation current output device includes a transformer control device that controls an output voltage of the output voltage variable transformer in accordance with a temperature of the field winding. Generator excitation device. The startup excitation current output device has a startup excitation current control device that controls the startup excitation current output by the startup DC converter according to the temperature of the field winding. The generator excitation apparatus according to claim 5, wherein The start-up DC converter uses a thyristor or an insulated gate bipolar transistor as a rectifying element, and the start-up excitation current control device controls the thyristor or the insulated gate bipolar transistor. The generator excitation device according to claim 10.

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