JPS58159699A - Exciter for electric machine - Google Patents

Abstract

PURPOSE:To eliminate an exciting current transformer exclusively for excitation by supplying the exciting current of a generator from a storage battery when the current of the generator is abruptly increased or when the generator voltage is abnormally decreased. CONSTITUTION:An automatic voltage regulator 5 normally controls the conductor for an exciting thyristor 6 is response to the detected voltage value from an instrument transformer 4. When a shorticircuit trouble occurs in the output circuit of a generator 1 so that the detected voltage at an instrument transformer 4 decreases abnormally or the detected current value of the instrument current transformer 9 abruptly increases, an abnormal detector 10 sets a power transistor 12 in conducted state, and exciting current is supplied from a storage battery 11 to the exiting coil 2. In this manner, the current necessary to recover the voltage of the generator or the operation of the protecting relay is supplied.

Description

[Detailed description of the invention] The present invention relates to an excitation device for an electric machine.

A conventional excitation device for this purpose is shown in FIG. In the figure, / is the generator, /a is the armature winding of the generator a/, /b is the excitation winding of the generator /, and the IC is! 1R machine, /d
is the alternating current generator, ko is the excitation winding of the alternator/d, 3 is the excitation transformer, da is the instrument transformer, S is the automatic voltage regulator,
6 is a thyristor, 7 is an excitation current transformer, and 7 is a rectifier.

Next, the operation will be explained. The voltage generated by the alternator/d according to the DC current applied to the excitation winding rectifier is determined by the rectifier/d.
It is rectified by C and given to the excitation winding @ t b, so that the generator / is its electric machine pre-winding! ! Generates an output voltage on the #1 string l.

On the other hand, the output voltage of the generator is controlled by conducting conduction control of the secondary voltage of the excitation transformer 3 using the si-risk 6.
However, conduction control of the thyristor 6 is performed by applying a line! This is done by transforming the output voltage of the above generator/from the instrument transformer 4j and comparing it with the regulation A1 using the automatic voltage regulator 5.

In addition, by rectifying the current of the excitation current transformer 7 with a rectifier g and applying it to the excitation winding, excitation proportional to the load current of the generator is obtained. In the event that the output circuit of the generator is short-circuited, the fault current required to operate the protective relay (not shown) must be supplied from the generator.
The fault current is supplied by applying the secondary current value in the excitation current transformer to the excitation winding 2 via the rectifier g.

In this way, output voltage control is performed by both voltage control in the instrument and excitation transformers V and 3, and current control in the excitation current transformer. It is designed as a primary current value and a secondary current value that are proportional to the current.

Since the conventional excitation device is configured as described above, the excitation current transformer 7 must be newly designed and manufactured for each generator so that the primary current value and secondary current value are proportional to the load current. In addition, the switchboard that houses the excitation device is newly designed each time.

The drawback was that it had to be manufactured.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and when the generator current suddenly increases abnormally or when the generator voltage abnormally decreases, the excitation current of the generator can be changed to It is an object of the present invention to provide an excitation device for an electric machine that eliminates the need for a dedicated excitation current transformer by supplying power from a storage battery through conduction control of a transistor.

Hereinafter, one embodiment of the present invention will be described based on FIG. 2. In No. 21￥1, the excitation current transformer 7 and rectifier g shown in FIG. An abnormality detection device 10 that inputs both side output values of the current detection value from, and an excitation winding of the storage battery // in the event of an abnormality. A power transistor saw whose conduction is controlled by the abnormality detection device 10 so as to make the uK connection is provided. The other configurations are the same as those in FIG. 1, so explanations will be omitted.

In the above configuration, as in the conventional case, the electrical conduction of the thyristor 6 is controlled by the instrument transformer and the automatic voltage regulator S to apply the secondary voltage of the excitation transformer 3 to the excitation winding-1, thereby generating a generator. The output voltage of / is controlled, but it is not controlled by the excitation current transformer.

For example, if a short circuit occurs in the output circuit of the generator, and the voltage detected at the voltage transformer drops abnormally or the current detected at the measuring current transformer suddenly suddenly increases, an abnormality will be detected. The device io detects an abnormality in at least one of them, outputs a signal that makes the power transistors /, 2 conductive, and supplies excitation current from the storage battery / to the excitation winding -, thereby starting the generator /. This means that the current necessary for voltage recovery or protection relay operation can be supplied.

In the above embodiments, the generator l is a single-phase alternating current generator with brushless excitation, but it may be a three-phase alternator with other excitation methods, or it may be a synchronous motor.

As described above, according to the present invention, there is no need for an excitation current generator designed and manufactured exclusively for excitation for each generator.
Since the configuration is configured such that excitation is supplied from the storage battery only in the event of an abnormality, there is no need to newly design and manufacture a switchboard for housing the excitation device, and there is an effect that a compact and inexpensive device can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a conventional excitation device, and FIG. 2 is a block diagram showing an excitation device according to an embodiment of the present invention. In the figure, / is the generator, U is the excitation winding,
3 is an excitation transformer, DA is an instrument transformer, 5 is an automatic voltage regulator, 6 is a thyristor, D is a measurement current transformer, 10 is an abnormality detection device, // is a storage battery, /- is a power transistor. be. Banknote 2 drawing 4

Claims (1)

[Scope of Claims] (1) Conducting conduction control of the thyristor using the output of an instrument transformer that detects the voltage of the electric machine. Applying the output of the excitation transformer from K to the excitation winding of the electric machine, In an excitation device for an electric machine that controls the voltage of the electric machine, both a voltage detection value from the potential transformer and a current detection value from a current transformer that detects a load current of the electric machine are controlled. an abnormality detection device that inputs a detected value; a power source that supplies a direct current to the excitation winding of the electric machine during an abnormality;
a switching element connected between the power supply and the excitation winding and responsive to a signal from the abnormality detection device, and the signal from the abnormality detection device is normally connected between the power supply and the excitation winding. The switching element is controlled to disconnect the switching element, and when the detected voltage value from the potential transformer abnormally decreases or the detected current value from the current transformer abnormally increases rapidly, the excitation from the power source is controlled. An excitation device for an electric machine, characterized in that the switching element is controlled so as to supply a direct current to the winding. (g) The excitation device for an electric machine according to claim 1, wherein the power source is a storage battery. (3) The electric machine-like excitation device according to claim 1 or 1, wherein the switching element is a power transistor.