阅读说明：本技术 一种发电机拖动阶段保护方法 (Protection method for dragging stage of generator ) 是由 郁小兵 邓洪刚 毕天盛 杨文彬 于 2021-08-30 设计创作，主要内容包括：本发明提供一种发电机拖动阶段保护方法,该方法是在隔离闸刀后加装熔断器。本发明通过加装熔断器对启动装置输出端及其出线电缆的故障点进行切断,安装便捷；利用较小的投资成本即可防止可能出现的拖动阶段变频启动装置及其出线电缆故障导致的严重后果；具有良好的市场前景,适于推广使用。(The invention provides a protection method for a generator in a dragging stage. The invention cuts off the fault point of the output end of the starting device and the outgoing cable thereof by additionally arranging the fuse, and the installation is convenient; the serious consequences caused by the frequency conversion starting device at the dragging stage and the fault of the outgoing cable of the frequency conversion starting device can be prevented by using lower investment cost; has good market prospect and is suitable for popularization and application.)

1. A protection method for a generator dragging stage is characterized by comprising the following steps: the method is to install a fuse after the isolating knife switch.

2. The generator dragging phase protection method according to claim 1, characterized in that: the specific method comprises the following steps: a group of fuses is added to each phase of an inlet of an SFC isolation switch blade of the generator outlet circuit breaker system GCB, and a fuse box is additionally arranged below the SFC isolation switch blade of the generator outlet circuit breaker system GCB.

3. The generator dragging phase protection method according to claim 2, characterized in that: the number of fuses is at least 3.

4. A protection method for a generator dragging stage is used for protecting a variable frequency starting device and an outgoing cable thereof.

Technical Field

The invention belongs to the technical field of variable frequency starting of a gas turbine power plant, and particularly relates to a starting device for protecting a generator in a dragging stage and a method for protecting an outgoing cable of the starting device.

Background

The generator in a gas turbine or a pumped storage power station needs to be dragged by using a frequency converter starting device as a synchronous motor, when the output end of the starting device and a cable of the starting device have short-circuit faults in the dragging stage, the generator can continuously provide short-circuit current for a fault point due to the existence of an excitation power supply and residual magnetism of the generator, the short-circuit current is larger due to the fact that the rotating speed of the generator is far lower than the rated rotating speed and the impedance value of a stator coil of the generator is lower, and equipment is extremely easy to damage when the short-circuit current is broken because a device for cutting off the short-circuit current is not arranged in a loop in the conventional configuration.

Therefore, it is an urgent need for those skilled in the art to solve the above problems by developing a mechanism or method capable of protecting the generator traction phase.

Disclosure of Invention

In order to solve the problems, the invention discloses a protection method for a dragging stage of a generator.

In order to achieve the purpose, the invention provides the following technical scheme:

a protection method for a generator in a dragging stage is characterized in that a fuse is additionally arranged behind an isolation knife switch.

Further, the specific method comprises the following steps: a group of fuses is added to each phase of an inlet of an SFC isolation switch blade of the generator outlet circuit breaker system GCB, and a fuse box is additionally arranged below the SFC isolation switch blade of the generator outlet circuit breaker system GCB.

Further, the number of fuses is at least 3.

A protection method for a generator in a dragging stage is used for protecting a variable frequency starting device and an outlet cable thereof.

Compared with the prior art, the invention has the following beneficial effects:

1. the output end of the starting device and a fault point of an outgoing cable of the starting device are cut off by additionally arranging the fuse, so that the starting device is convenient and fast to install;

2. the serious consequences caused by the frequency conversion starting device at the dragging stage and the fault of the outgoing cable of the frequency conversion starting device can be prevented by using lower investment cost;

3. has good market prospect and is suitable for popularization and application.

Drawings

Fig. 1, installation schematic of the invention.

List of reference numerals: 1. and a fuse.

Detailed Description

The technical solutions provided by the present invention will be described in detail below with reference to specific examples, and it should be understood that the following specific embodiments are only illustrative of the present invention and are not intended to limit the scope of the present invention.

The embodiment is a protection method for a generator in a dragging stage, and the method is characterized in that a fuse is additionally arranged behind an isolation knife switch.

Fig. 1 shows a connection diagram of a variable frequency starting device of a generator of a current gas turbine power plant and an outgoing cable thereof, a maximum current of a fuse applied to a medium-voltage loop is 400A, a maximum current of a generator in a dragging stage exceeds 1000A, the embodiment is provided with more than 3 fuses 1, and the more than 3 fuses 1 are connected in parallel for use, so as to prevent the phenomenon that the fuses one by one are blown out during operation due to unbalanced shunting of the fuses 1.

During specific installation, a group of fuses 1 is added at each phase of an inlet of an SFC isolation switch blade of a generator outlet circuit breaker system GCB, and a fuse box is additionally arranged below the SFC isolation switch blade of the generator outlet circuit breaker system GCB; and for safety consideration when the fuse is replaced, the auxiliary contact of the fuse needs to simultaneously lock the isolation knife switch in the GCB and the switch-on of the isolation high voltage side switch.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the technical solutions, and those skilled in the art should understand that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions, and all the modifications and equivalent substitutions should be covered by the claims of the present invention.