JPS63240328A - Controller for parallel making of generator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention suppresses the motoring phenomenon that occurs when a turbine generator is connected to a power grid, for example in a Hitsuno power plant. This invention relates to a system parallel control device for generators.

(Prior art) Generally, when a generator is connected to a grid, it is known that a so-called motoring phenomenon occurs in which the generator receives power from the grid and rotates due to frequency fluctuations in the grid. .

A means for preventing the occurrence of a motoring phenomenon in a conventional power generator system parallel connection [15] will be explained with reference to the turbine control system shown in FIG. Main steam is guided to a steam turbine T through a control valve Cv and driven, and a turbine generator T is directly connected to the steam turbine T.
In a thermal power plant that generates electricity by driving the generator TG, the generator TG can be switched on by closing the circuit breaker 52G.
It is structured in such a way that it is arranged in a systematic manner.

The steam turbine T and the turbine generator TG are operated by a control valve C.
It is controlled by adjusting the opening degree of V, and an electric governor is used in this control system.

The opening command Scv of the control valve Cv is the speed deviation signal S1
This is a combination of the speed control signal S2 obtained through the speed adjustment rate So and the load setting signal 83 from the load setting device.

The load setting signal S3 and the initial load setting signal S4 are input to the adder 1 through the switching contacts tal and tb+, and the output side of the adder 1 is connected to the dividers 2a and 2b and the integrator through the switching contacts ta2 and tb2. 3, the output of this integrator 3 is fed back to the adder 1, and
It is input to the adder 4 and added to the speed control signal S2.
V opening command S. .

make.

(Problems to be solved by the invention) In the conventional control system configured in this way, the generator
"In order to prevent the motoring phenomenon that occurs when parallel entry into the G system, an AND condition between the automatic control system AO's parallel command AO+ and the initial load setting arrival command AO2 is used to prevent motoring from parallel entry to the initial load. The load setting signal S3 of the early relays 1 to 1 is supplied to provide sufficient torque to the steam turbine T.

However, this control system is effective when the system is extremely stable, such as in Japan, but when the frequency rises above the rated value in systems with large frequency fluctuations, such as in overseas plants, the speed control signal S2 The lower signal of the load setting signal @S3 exceeds the higher signal of the control valve CV, and the opening command S of the control valve CV is
. , is narrowed down to below the no-load opening, causing a motoring phenomenon.

The purpose of the present invention is to avoid frequency fluctuations of a certain magnitude; N! To provide a system parallel control device for a generator that reliably suppresses the occurrence of a motoring phenomenon without being affected by it.

[Structure of the Invention] (Means and Effects for Solving the Problems) The system parallel control device for a generator according to the present invention is an automatic control system for a steam turbine and a turbine generator. The present invention is characterized in that a dead zone is provided for the speed deviation signal between immediately after parallel entry and when the initial load is reached.

In the present invention, when a generator is connected to a system, the relay is operated immediately after the parallel connection to make the speed deviation signal zero, so that motoring prevention control can be reliably performed even in systems with large frequency fluctuations. . When the initial load setting position is reached, normal speed governing control begins.

(Example) The present invention will be explained below with reference to the embodiment shown in FIG.

In FIG. 1, the same reference numerals as in FIG. 2 indicate the same parts, so the explanation thereof will be omitted.

In the generator grid entry control device according to the present invention, a function is maintained in the system of the speed deviation signal S1 to provide a dead zone between immediately after the generator TG enters the grid and until the initial load setting is reached. It is characterized by:

That is, in FIG. 1, a relay R is provided in the system of the speed deviation signal S1, and parallel input commands AO1,
Initial load setting reached AO2 and speed deviation 1±0.3%l
Operates under the AND condition of AO3 and opens its contact t,
If the speed deviation signal S1 becomes larger than the dead band of deviation 1±0.3%1, it is detected by comparator A and relay R is activated.
The control system is configured so that the relay Ry is restored when the comparator B detects that the load setting signal S3 roughly reaches the initial load setting signal S4.

Next, the operation of the system parallel control device for generators according to the present invention will be explained. In Fig. 1, the speed of the steam turbine T is synchronized with the system frequency by a parallel command by turning on the circuit breaker 52G, and if the system is stable at the rated speed, the turbine rotation speed is also stable at the rated speed. At this time, the speed deviation is zero and the speed control signal S2 is also almost zero.

However, if the system frequency rises above the rated value, the speed control signal S2 outputs a lower signal. Then, the output of the turbine T is reduced, and the power generation IITG is rotated by receiving the power from the system.

This causes a so-called "shittering" phenomenon, which adversely affects the power generation INTG.

Therefore, in the present invention, the relay Ry is operated by the command AOI of the automatic control system ΔAO, and its contact point t
By opening the circuit, the speed deviation signal S1 is forced to zero. At this time, the speed deviation signal S1 has a value sufficiently smaller than the deviation 1±0.3%1 since the speed of the turbine T has been equalized.

- The force load setting signal S3 increases at a fast rate 1~ from the no-load setting to the initial load setting after parallel input.

While this relay RV is operating, the speed pot difference signal S1
When the error becomes larger than the dead zone of 1±0.3%1, comparator A detects this and returns relay RV to close contact t. Then, when the speed is regulated by the speed deviation signal S1 and enters the dead zone of deviation 1±0.3%1, the relay RV is activated again.
operates to open contact t.

When the rough load setting signal S3 reaches the initial load setting signal S4, it is detected by comparator B and relay RV
By returning the contact t and closing the contact t, the motoring prevention control is completed and normal speed regulating control begins.

Note that domestic power systems are extremely stable, so there is no need to particularly adopt motoring prevention control as in the present invention. However, in systems with large frequency fluctuations such as those in overseas plants, speed control signal S2 may be The lowering side signal is the load setting signal S
3, the control valve C of the steam system of the turbine T
The motoring phenomenon occurs when the V opening command SCV is narrowed down to a value below the limit. Therefore, in systems with large frequency fluctuations such as those in overseas plants, this is useful in preventing the phenomenon of stagnation when the generator TG is connected to the system.

[Effects of the Invention] As described above, in the present invention, when a generator is connected to a grid, the speed deviation signal is forced to zero from immediately after the generator is connected until the load setting signal reaches the initial load position. By doing so, a dead zone is provided for the speed deviation signal even with the magnitude of the system frequency fluctuation 4 [Plan 1~], and it is possible to carry out reliable and highly reliable monotalling prevention control.

[Brief explanation of drawings]

FIG. 1 is a control system diagram showing a power generation (multi-system parallel control device) according to the present invention, and FIG. 2 is a control system diagram showing a conventional power generator system parallel control device. T...Steam Turbine TG... Turbine generator CV... Control valve 1.4... Heater 2a, 2b... Pressure divider 3... Integrator △, B... Comparator AO, AAO... Synchronous control system Ry...Relay S2...Speed control signal (8733) Agent Patent attorney Yoshiaki Inomata (Idiot)
1 person)

Claims (1)

[Claims] (1) In the automatic control system for steam turbines and turbine generators, when the turbine generator is connected to the system, a dead zone is provided for the speed deviation signal from immediately after the turbine generator is connected to the system until the initial load is reached. A power generator system parallel control device characterized by: