JP2880167B2 - AC excitation generator motor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AC-excited generator motor, and more particularly to an AC-excited generator motor that protects a power converter in an excessively high slip frequency state.

[Conventional technology]

As the AC-excited generator motor, as proposed in JP-B-53-7628 and JP-B-57-60645,
There is a system in which active power and reactive power are controlled by controlling an exciting current of an AC exciter.

This type is most suitable for use as an active power adjusting device or a reactive power adjusting device that operates quickly while preventing turbulence and step-out.

In addition, a variable-speed pumped-storage power generator using a cycloconverter as a frequency converter for AC excitation and a pump-turbine directly connected to an AC-excited synchronous machine, as was announced at the Japan Society of Electrical Engineers Kansai Branch Conference in 1985, It is used for power system frequency adjustment and exhibits excellent effects.

The same system is used for the 1986 IEEJ National Convention.
No. 1026, introduced in the Electric Association of Japan magazine, March 1986, p. 34.

Furthermore, regarding the specific method of coordinating the AC excitation control device and the pump turbine guide blade control device, see Japanese Patent Application No.
Japanese Patent Application No. -210004, Japanese Patent Application No. 60-210005, and Japanese Patent Application No. 61-99844.

In each of the AC excitation generator motors disclosed in the above-mentioned documents, a method is employed in which the phase is controlled by the amplitude of the AC excitation current using the voltage phase of the AC system as a reference signal.

FIG. 3 shows a configuration of a conventionally proposed AC-excited generator motor, in which a main transformer 3 is connected to an AC system 1 and a low-voltage side of the main transformer 3 is connected via a synchronous breaker 4. The armature winding 5a of the AC excitation synchronous machine 5 is connected.

Further, a frequency converter 6 is connected to the low voltage side of the main transformer 3 via the input side circuit breaker 2.

The frequency converter 6 includes an excitation transformer 7 provided with the input side circuit breaker 2 described above connected to the input side and provided for each phase.
And a thyristor power converter 8 connected to the output side of the exciting transformer 7 and connected to the exciting winding 5b of each phase of the AC exciting synchronous machine 5.

The frequency converter 6 converts the power frequency of the AC system 1 stepped down by the exciting transformer 7 into low-frequency AC power by the thyristor power converter 8.

The low-voltage side of the main transformer 3 is connected to an input terminal of a voltage phase calculator 11 via a voltage transformer 10 for detecting a voltage phase θ _v of the AC system 1. The terminal is connected to the input terminal of the slip phase calculator 13.

Furthermore, the resolver apparatus 12 for detecting a rotational phase theta _r expressed in electrical angle of the AC energization synchronous machine 5, AC-excited synchronous machine 5
The output terminal of the resolver device 12 is connected to the input terminal of the slip phase calculator 13 described above.

The voltage transformer 10, the voltage phase calculator 11, the slip phase calculator 13 and the resolver device 12 constitute a phase detector 9.

A current transformer 18 is connected to the low voltage side of the main transformer 3, and the output side of the current transformer 18 is connected to the voltage transformer.
The output side of 10 is connected to the input terminal of measuring instrument 19, and the output terminal of measuring instrument 19 is connected to the input terminals of automatic active power control device 20 and automatic voltage control device 21, respectively.

Further, an external output command signal Po is connected to an input terminal of the automatic active power control device 20, and an external output command signal Vo is connected to an input terminal of the automatic voltage control device 21. The output terminal of the automatic voltage controller 21 is connected to the input terminal of the exciting current controller 14.

Further, the output terminal of the slip phase calculator 13 is also connected to the input terminal of the exciting current control device 14,
The pulse phase shifters 16 are connected to the output terminals for each of the fourteen phases, respectively, and these pulse phase shifters 16 are connected to the thyristor power converters 8 of the respective phases of the frequency converter 6.

In the conventionally proposed AC-excited generator motor, the voltage phase θ _{v of the} AC system 1 output from the voltage phase calculator 11
And the rotational phase θ _r of the AC excitation synchronous machine 5 output from the resolver device 12, the slip phase calculator 13 calculates the slip phase θ _s = θ _v −θ _r , and inputs the slip phase to the excitation current control device 14. You.

In addition, the output signal of the measuring instrument 19 and the external output command signal
From the automatic active power control device 20 to which Po is input, the current command _Iq is input to the excitation current control device 14, and the automatic voltage at which the output signal of the measuring instrument 19 and the external output command signal Vo are input. The current command _Id is supplied from the control device 21 to the excitation current control device.
Entered in 14.

Then, the exciting current control unit 14, and the sliding phase theta _s of the amplitude of the command current of 3-phase alternating current rotating with the phase, is by connexion adjusted to the current command I _q, I _d the two axes perpendicular to each other, AC The firing angle signal 15 of the thyristor power converter 8 is input to the pulse phase shifter 16 so that the current of the excitation winding 5b of the excitation synchronous machine 5 matches the above-described command current. The ignition pulse signal of the thyristor power converter 8
17 is output.

Here, the adjustment by the excitation current control device 14 is described in
The method is carried out according to the methods described in JP-A-7628 and JP-B-57-60645.

That is, by controlling the active power output by adjusting the current component I _q of the slip phase theta _s and the same phase, the slip phase theta _s
By adjusting the current component I _d with the 90 ° phase difference,
Controlling voltage.

In this case, the active power output and the voltage of the AC system 1 are obtained by converting the output signals of the current transformer 18 and the voltage transformer 10 into DC signals by the measuring instrument 19, and the automatic active power controller 20 and the automatic power controller 20, respectively. Input to the power control device 21.

The AC-excited generator motor is operated such that a prime mover such as a water turbine (not shown) is directly connected to the AC-excited synchronous machine 5 and the output of the prime mover is adjusted so that the rotation speed is within an allowable range. Is done.

[Problems to be solved by the invention]

In the above-described conventionally proposed AC-excited generator motor, the thyristor power converter 8 in the case where the rotation frequency decreases or increases and the slip frequency of the AC-excited synchronous machine 5 deviates from a preset operation band. No consideration is given to protection.

Generally, when the AC excitation synchronous machine 5 is suddenly stopped at the time of failure due to a mechanical factor other than the main circuit such as a cooling system, in order to prevent a sudden increase in the rotation speed at the time of the stop operation, guide blades on the turbine side are used. And AC excitation synchronous machine 5
To shut down the circuit breaker 4 for synchronizing input on the armature side of the AC excitation synchronous machine 5 in a substantially no-load operation state, thereby causing an abrupt stop.

However, in the above-described conventionally proposed AC-excited generator motor, when there is a difference in the active power between the turbine input and the output of the AC-excited synchronous machine 5 during a sudden stop, the rotation of the AC-excited synchronous machine 5 is stopped. The speed may change and the slip frequency may become excessive.

If the slip frequency becomes excessive in this manner, there is a possibility that the ignition pulse signal 17 input to the thyristor power conversion device 8 will be lost or the positive and negative groups of the thyristor power conversion device 8 will be short-circuited.

The present invention has been made in view of the current situation of the AC-excited generator motor described above, and its object is to reduce the slip frequency by the sudden stop during the power generation operation or the input cutoff during the pumping operation as described above. It is an object of the present invention to provide an AC-excited generator motor device that can protect the thyristor power converter in the case where is excessive.

[Means for solving the problem]

To achieve the above object, an AC excitation generator motor having a primary winding connected to an AC system, a power converter connected to a secondary winding of the AC excitation generator motor and outputting an excitation current, and a power converter A pulse phase shifter that outputs a firing pulse signal for driving the semiconductor element of the present invention, and an excitation current control device that outputs a firing signal to the pulse phase shifter based on an externally supplied output command signal. In the excitation generator motor, the short-circuit means provided between the secondary winding of the value-pitch AC excitation generator motor and the power converter, and the slip frequency of the AC excitation generator motor deviated from a predetermined slip frequency band. Excessive slip detector and short-circuit means short-circuit the circuit in accordance with the detection signal of the excessive slip detector, and the exciting current control device controls the exciting current from the power converter in accordance with the detection signal of the excessive slip detector. Decreases A stop means for outputting a firing signal to the pulse phase shifter so as to stop the supply of the firing pulse signal to the pulse phase shifter after the exciting current of the power converter becomes zero. Things.

[Action]

ADVANTAGE OF THE INVENTION According to the AC excitation generator motor apparatus of this invention, when stopping operation | movement of a pulse phase shifter and stopping operation | movement of a power exchanger, it is provided between the secondary winding of an AC excitation generator motor and a power converter. By operating the short circuit means, the power converter can be protected from a high voltage generated in the exciting winding.

〔Example〕

Hereinafter, an embodiment of the present invention will be described in detail with reference to FIG. 1 and FIG.

FIG. 1 is a block diagram showing the configuration of the embodiment of the present invention, and FIG. 2 is a waveform diagram showing the operation of the embodiment of the present invention.

As shown in FIG. 1, the embodiment of the present invention is different from the conventionally proposed AC-excited generator motor described with reference to FIG. 3 in that the output terminal of the voltage phase calculator 11 is connected to the system frequency detector. The output terminal of the resolver device 12 is connected to the input terminal of the rotational frequency detector 23, and the output terminals of the system frequency detector 22 and the rotational frequency detector 23 are connected to the subtractor 30. Is connected to the input terminal of

The output terminal of the subtractor 30 is connected to the input terminal of the excessive slip detector 24, and a stop signal 24c issued from the output terminal of the excessive slip detector 24 is input to the timer circuit 26, and the gate signal from the timer circuit 26 The shift signal 27 is input to the exciting current control device 14, and the gate block signal 28 from the timer circuit 26 is input to the pulse phase shifter 16.

Also, the OFF signal 24a output from the excessive slip detector 24
Is input to the synchronous closing circuit breaker 4 and the input side circuit breaker 2,
Similarly, the ON signal output from the excessive slip detector 24 is supplied to a thyristor switch connected between a connection point between the thyristor power converter 8 of each phase and the excitation winding 5b and a neutral point of the excitation winding. 25 are entered respectively.

In the embodiment of the present invention having such a configuration, the current transformer 18, the voltage transformer 10, and the measuring instrument 19 constitute a power detector, and the timer circuit 26 constitutes a stopping means.

The operation of the embodiment of the present invention having the above-described configuration will be described below.

Frequency f _o of the AC system 1 is detected by the system frequency detector 22, the rotational frequency theta _r of AC-excited synchronous machine 5 is detected by the rotational frequency detector 23, by the subtractor 30 connexion slip frequency signal f _s = f _o -f _r is computed and input to the slip excessive detector 24.

In the slip excessive detector 24, it has detected the condition of the slip frequency signal f _s, for example, by the sudden stop of the AC excitation generator-motor apparatus connexion, the slip frequency signal f _s is the second diagram (a)
As shown in FIG. 2, when it is detected that the operating band is set between the set values f _smax and f _smin across zero, the detection signal is excessively slipped as shown in FIG. Output from 24.

As shown in FIGS. 2 (c), 2 (d) and 2 (e), this detection signal is inputted as an OFF signal 24a to the circuit breaker 4 for synchronizing and the input side circuit breaker 2, and an ON signal 2a is outputted to the thyristor switch 25.
4b and input to the timer circuit 26 as a stop signal 24c.

The OFF operation of the synchronizing circuit breaker 4 and the input circuit breaker 2 is started by the OFF signal 24a, the thyristor switch 25 is turned on by the ON signal 24b, and the armature winding 5a and the exciting winding are turned on. 5b is short-circuited.

In response to the stop signal 24c, a gate shift signal 27 is input from the timer circuit 26 to the exciting current control device 14 as shown in FIG. 2 (f), and the exciting current control device 14 Signal 15 so as to forcibly narrow down to zero.
Is input to the pulse phase shifter 16.

Therefore, the exciting current of each phase, as shown in FIG. 2 (g) are narrowed down to zero, long enough time t after ₁ against time sufficient to narrow the exciting current to zero, from the timer circuit 26 second
A gate block signal 28 is output as shown in FIG.

The gate block signal 28 is input to the pulse phase shifter 16, and the pulse phase shifter 16 stops outputting the firing pulse signal 17 as shown in FIG. 2 (i).

The reason why the gate shift operation is performed before the gate block operation is that there is a possibility that the excitation current may not be reduced to zero only by the gate block operation depending on the phase of the excitation current.

In this manner, according to the embodiment of the present invention, the thyristor power converter 8 can be safely stopped and protected in the event of excessive slippage that causes a failure in the thyristor power converter 8.

When the thyristor power converter 8 is stopped, the exciting winding 5b, which is its output winding, is short-circuited by the thyristor switch 25, so that the exciting winding 5b is opened when the synchronous circuit breaker 4 is opened.
Thyristor power conversion device 8 can be prevented from being generated at high voltage.

〔The invention's effect〕

As described above, in the AC excitation generator motor of the present invention, when the operation of the pulse phase shifter is stopped to stop the operation of the power converter, the secondary winding of the AC excitation generator motor and the power converter are connected. By operating the short-circuit means provided therebetween, the effect that the power converter can be protected from the high voltage generated in the exciting winding can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, and FIG.
FIG. 3 is a waveform diagram showing the operation of the embodiment of the present invention, and FIG. 3 is a block diagram showing the configuration of a conventionally proposed AC-excited generator motor. 1: AC system, 2: Input side circuit breaker, 3: Main transformer, 4:
Synchronous circuit breaker, 5: AC excitation synchronous machine, 5a: armature winding, 5b: excitation winding, 8: thyristor power converter, 10:
Voltage transformer, 11… Voltage phase calculator, 12… Resolver device,
13: slip phase calculator, 14: exciting current controller, 16: pulse phase shifter, 18: current transformer, 20: automatic active power controller, 21: automatic voltage controller, 22: system frequency detector, 23
... Rotation frequency detector, 24 ... Excessive slip detector, 26 ... Timer circuit.

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Junichi Shiozaki 3-1-1, Sachimachi, Hitachi, Ibaraki Pref. Hitachi, Ltd. Hitachi Plant (72) Ikuo Miyashita 3-1-1, Sachimachi, Hitachi, Ibaraki 1 Hitachi, Ltd. Hitachi Plant (72) Inventor Hiroto Nakagawa 3-3-22 Nakanoshima, Kita-ku, Osaka City, Osaka Prefecture Kansai Electric Power Co., Inc. (56) References JP-A-55-125100 (JP, A JP-A-62-171499 (JP, A) JP-A-62-255585 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H02P 9/00-9/48

Claims (1)

(57) [Claims] An AC excitation generator motor having a primary winding connected to an AC system, a power converter connected to a secondary winding of the AC excitation generator motor and outputting an excitation current, An alternating current comprising a pulse phase shifter that outputs a firing pulse signal for driving a semiconductor element, and an excitation current control device that outputs a firing signal to the pulse phase shifter based on an output command signal supplied from the outside. In the excitation generator motor, the short-circuit means provided between the secondary winding of the AC excitation generator motor and the power converter, and the slip frequency of the AC excitation generator motor deviates from a predetermined slip frequency band. An excessive slip detector for detecting that, the short-circuit means short-circuits a circuit according to a detection signal of the excessive slip detector, and the exciting current control device controls the electric power according to a detection signal of the excessive slip detector. conversion A firing signal to the pulse phase shifter is output so that the exciting current from the power converter decreases, and after the exciting current of the power converter becomes zero, the supply of the firing pulse signal of the pulse phase shifter is performed. An AC-excited generator motor, comprising stopping means for stopping.