JPH07245998A - Starter of generation facility provided with brushless exciter - Google Patents

Abstract

PURPOSE:To make excitation available both at the beginning of start-up and at the low-speed operation by switching a power source from a static-type frequency converter to a permanent magnet generator by switching a breaker when the number of rotations reaches a specified one. CONSTITUTION:At the low-speed operation, a breaker (SW) 14a is closed and SW's 14b, 14c are opened. The speed of a motor 1 is detected by a speed detector 7. Where the rated number of rotations is N and the detected number of rotations is 'n', a gate pulse circuit 8 gives such a signal to a frequency converter 9 heat the the static- type frequency converter for exciter 9 may generate a.c. current of a constant amplitude for a field winding of an exciter stator which is a polyphase distributed winding to generate a rotating magnetic field flux which rotates in the direction reversal to the rotating direction of a rotor at the frequency of (N-n)/60. On the other hand, when the power of a permanent magnet generator 4 reaches such a value as to allow current corresponding to a no-load field current to flow in the field winding of the motor, an SW6 and the SW14a are opened and the SW's 14b, 14c are closed. By this method, a current source for the stator field winding is switched from the frequency converter 9 to the permanent magnet generator 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a starting device for a gas turbine power generation facility or a combined cycle power generation facility which is started by using a static frequency converter.

[0002]

2. Description of the Related Art In recent years, as the demand for electric power has increased, the capacity of gas turbines and combined cycles consisting of gas turbines and steam turbines in power generation equipment has increased, and the starting methods of these gas turbines have been compared with conventional torque converters. Instead of a combination of cranking motors, a method of starting a synchronous generator as a synchronous motor using a static frequency converter such as a thyristor starter is in the spotlight. The starting method of the power generation equipment using the static frequency converter will be described below with reference to FIG. Although FIG. 6 relates to the gas turbine power generation facility, the same applies to the combined power generation facility. The gas turbine 2 cannot rotate by itself until it reaches a certain rotation speed. Therefore, it is necessary to externally rotate the gas turbine 2 until it reaches a rotation speed at which the gas turbine 2 can rotate by itself. One of the methods is to rotate the synchronous generator motor 1 as a synchronous motor by using a static frequency converter.
In this method, in order to use the synchronous generator motor 1 as a synchronous motor, the armature of the synchronous generator motor 1 must be supplied with a current having a frequency synchronized with the rotation of the synchronous generator motor 1. Therefore, the alternating current from the grid is converted into a current having a frequency synchronized with the rotation speed of the synchronous generator motor 1 by using the static frequency converter 5, and is supplied to the synchronous generator motor 1. In addition, the field current is also transmitted via the automatic voltage adjusting device 11.
Supplied from the grid. When the gas turbine 2 reaches a rotational speed at which it can rotate by itself, the disconnector 6 is opened and the static frequency converter 5 is disconnected from the synchronous generator-motor 1.

On the other hand, there is an increasing demand for brushless exciters because there is no arcing problem in the brush portion and the ease of maintenance. Furthermore, since it is not necessary to prepare a current source to excite the field of the exciter, a brushless exciter equipped with a generator having a permanent magnet rotor coaxial with the rotor of the generator / exciter should be noted. I am collecting. Using FIG. 5 below,
A brushless exciter including a permanent magnet generator will be described. As the synchronous generator motor 1 rotates, the permanent magnet rotor 19 of the permanent magnet generator 4 rotates at the same time.
Therefore, an electromotive force is generated in the armature winding 20a of the permanent magnet generator 4. The brushless exciter 3 is a kind of rotating armature type generator. Due to the electromotive force generated in the armature winding 20a, a DC current is supplied to the field winding 17c via the automatic voltage regulator 11 and is excited. As a result, a three-phase AC electromotive force is generated in the armature winding 17a of the brushless exciter 3. The three-phase alternating current generated by this electromotive force is converted into direct current by the rectifier 16, and the field winding 15b of the synchronous generator motor 1 is converted.
And is excited. A technique for starting a power generation facility using a static frequency converter is disclosed in Japanese Patent Laid-Open No. 4-54227, and a technique for a brushless exciter equipped with a permanent magnet generator is disclosed in Japanese Patent Laid-Open No.
There are examples in 4-355700.

[0004]

When a brushless exciter equipped with the permanent magnet generator shown in FIG. 5 is used as a starting device for a power generation facility using a static frequency converter, a sufficient electromotive force is generated at low speed rotation at the initial start. The permanent magnet generator armature winding 2
0a cannot be generated. Therefore, since the current supplied to the field winding 17c of the brushless exciter becomes small and the rotation speed is low, the armature winding 17a
In this case, a sufficient electromotive force is not generated, and as a result, a sufficient field current does not flow in the field winding 15b of the synchronous generator motor 1, and a torque for starting cannot be obtained.

Further, even if the field current supplied to the field winding 17c is obtained from the system, it is still impossible to generate sufficient electromotive force in the armature winding 17a at low speed rotation with the direct current. Have difficulty.

[0006]

A static frequency converter for a brushless exciter is provided separately from that for starting a generator, and a disconnector is provided on the output side of the static frequency converter for an exciter and an automatic voltage regulator. .

The stator field winding of the brushless exciter is a multi-phase distributed winding, and an alternating current having a constant amplitude is generated so as to generate a rotating magnetic field in a direction opposite to the rotation of the rotor at low speed rotation. At this time, if the rotation speed of the rotor is detected by a speed detector and the rotation speed is n (rpm), the rated rotation speed is N (rpm) and the frequency is (N-n) / 60 (Hz). To send an electric current. By doing so, the relative rotation speed of the rotating magnetic field seen from the rotor can be always maintained at N, and the brushless exciter can operate sufficiently.

When the number of revolutions has reached such that the permanent magnet generator and the brushless exciter can work sufficiently, the disconnector is switched to switch the power source from the static frequency converter to the permanent magnet generator.

[0009]

With the above structure, it is possible to start the power generation equipment by the static frequency converter using the brushless exciter equipped with the permanent magnet generator.

[0010]

【Example】

(Embodiment 1) Hereinafter, a first embodiment of the present invention will be described.

FIG. 1 shows the overall construction of this embodiment. FIG. 2 shows the relationship between the windings of the synchronous generator motor, the brushless exciter machine, and the permanent magnet generator in more detail.

At the initial low speed rotation when sufficient electromotive force cannot be obtained in the armature winding 17a of the brushless exciter 3,
The disconnector 14a is closed and the disconnectors 14b and 14c are opened. When the rotation speed of the synchronous generator motor 1 is detected by the speed detector 7 and the rated rotation speed N and the detected rotation speed are n,
With a frequency of (N−n) / 60 (Hz), a rotating magnetic flux in the direction opposite to the rotating direction of the rotor 18 has a constant amplitude so that it can be formed by the exciter machine stator field winding 17b which is a multiphase distributed winding. The gate pulse circuit 8 provides a signal to the frequency converter 9 so that the exciter static frequency converter 9 produces an alternating current. By doing so, the rotor 18
The relative rotation of the magnetic flux seen from above always means that the magnetic flux is rotating at the rated speed N.

On the other hand, the terminal voltage of the permanent magnet generator 4 is detected by the voltmeter 13, and the voltage of the permanent magnet generator 4 corresponds to the no-load field current in the field winding 15b of the synchronous generator motor 1. When the value which can pass the current is reached, the disconnector controller 12 opens the disconnector 6 and then disconnects the disconnector 14a.
Is opened and the disconnectors 14b and 14c are closed to switch the supply source of the current to the stator field winding 17b from the disconnector 9 to the permanent magnet generator 4. Then, the disconnector 6 is closed again. At this time, the stator field winding 17b has any two phases.

The parameter used for switching the disconnecting switch by the disconnecting switch control device 12 may be the rotation speed or the time as described in claims 2 and 3. This also applies to Examples 2 and 3 below.

(Second Embodiment) In the second embodiment, the connection between the stator field winding 17b and the automatic voltage regulator 11 and the disconnectors 14b and 14c are changed from those of the first embodiment as shown in FIG. When switching the current supply source to the stator field winding 17b from the disconnector 9 to the permanent magnet generator 4, the disconnector 14a is opened and the disconnectors 14d to 14f are closed. With such a configuration, excitation can be performed by all the phases of the stator field winding 17b, so that the thermal balance is improved.

(Embodiment 3) In the third embodiment, as shown in FIG. 4, the armature winding 20b of the permanent magnet generator is a winding having a polyphase distributed winding structure, and the automatic voltage regulator 11 is removed. The output from the voltmeter 21 is input to the disconnector 9 via the disconnector 14f.

When rotating at a low speed, the disconnector 14g is closed to
Open h and handle as in Example 1. The rotation speed causes the brushless exciter 3 and the permanent magnet generator 4 to operate sufficiently,
When the value reaches a value at which a current equivalent to a no-load field current can flow in the field winding 15b, the disconnector 14g is opened and 14h is closed.
Then, the terminal voltage of the synchronous generator motor 1 is detected by the voltmeter 21, the signal is input to the gate pulse circuit 8, and the disconnecting switch 9 is used instead of the automatic voltage regulator 11 by the control by the gate pulse signal of the gate pulse circuit 8. Used as an automatic voltage regulator.

[0018]

The output of the brushless exciter equipped with the permanent magnet generator has the same output characteristics as in the rated rotation, the restriction of the control of the rectification circuit is eliminated, and the excitation is possible even in the initial stage of start and in the low speed rotation.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of the present invention.

FIG. 2 is a circuit diagram showing the winding relationships of the synchronous generator motor, brushless exciter machine, and permanent magnet generator in more detail.

FIG. 3 is an explanatory diagram showing changes from the first embodiment of the second embodiment.

FIG. 4 is an explanatory diagram showing a modification of the third embodiment from the first embodiment.

FIG. 5 is an explanatory diagram showing a configuration of a brushless exciter including a conventional permanent magnet generator.

FIG. 6 is a circuit diagram showing a starting system of a power generation facility using a conventional static frequency converter.

[Explanation of symbols]

10 ... Electric power system busbar, 15a ... Synchronous generator motor stator (armature) winding, 22a-d ... Transformer, 23a-d ...
Circuit breaker.

Claims (3)

[Claims] 1. A single-shaft combined cycle comprising a gas turbine or a gas turbine and a steam turbine, a synchronous generator motor, a static frequency converter for starting the synchronous generator motor, a stator and a rotor winding having a multiphase distribution. A gas turbine power generation facility or a combined cycle power generation facility including a brushless exciter having a winding structure, a permanent magnet generator coaxially connected to the rotor of the synchronous generator motor and the rotor of the exciter, and an automatic voltage regulator A static frequency converter for an exciter that applies a current to a stator winding of the brushless exciter so that a rotating magnetic field whose direction is opposite to the rotation of the rotor is generated; and an output side of the automatic voltage regulator. A switch for detecting the voltage of the disconnector, the disconnector on the output side of the static frequency converter, and the voltage of the permanent magnet generator to switch the disconnector. A starting device for a power generation facility, which has a control device. 2. The starting device for power generation equipment according to claim 1, further comprising a control device for detecting a rotation speed of the rotor and switching the disconnector. 3. The starting device for power generation equipment according to claim 2, further comprising a timer and a control device for switching the disconnector at a time set by the timer.