JPS58133129A - Controller for combined cycle generation plant - 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 (Technical Field of the Invention) The present invention relates to a combined cycle power plant, in particular a power generator connected to two low voltage clamps of a plurality of 111 generators or a 3-unit pressure generator. The main purpose is to reduce the circulating current between the low voltage windings when the lid is connected, and to improve thermal efficiency compared to when each is used alone by combining them with nine control devices. ,
A combined cycle power generation ground is planned.

This method will be briefly explained below.

FIG. 1 shows an example of a system configuration of a combined cycle power generation plant. In the figure, the air line taken in is pressurized by the air pressure unit 1, the fuel is combusted in the combustor 2, the combustion becomes hot, and after driving the gas turbine 1 with its expansion force, exhaust heat is recovered. Water is heated in the heater 4 to generate steam, which is released as exhaust gas. On the other hand, the steam generated in the exhaust heat recovery tank 4 drives the steam turbine 5, and then turns into water again in the condenser 6. The output of the Smebin 3 and the Shiki turbine 5 is converted into electric energy of 411 JtK, which is supplied to an electric power system (not shown). According to the above method, it is common to configure a small power generator as a unit and a system that combines multiple units, or to treat the entire system as one set of power generation equipment.

Combined cycle %llf consisting of such a configuration
Although the Rant is composed of small-capacity power generation units (y), it is treated as one set of power generation equipment, so the main circuit of the generator is connected to each generator or external voltage transformer (main transformer) as in the past. If a unit system is adopted in which each unit is connected to the power transmission line via Wc and the in-station auxiliary power of each unit is supplied to each in-station transformer, it will be more economical, maintenance, inspection and Since this is disadvantageous in terms of operation, it is recommended to reduce the number of external pressure pumps by configuring the external pressure pump with three windings and connecting multiple generators to the secondary and tertiary sides. method is adopted.

Figure 2 shows the configuration e when the external voltage transformer has a three-winding configuration.
This shows l+. In FIG. 2, a plurality of generators 8 and a predetermined transformation voltage ti 1 ! B % Boost Poor Pressure Device 9-2
It is connected to the A system and B system of two low voltage windings, and is connected to the main bus g
1io, power is sent to the power transmission line and interrupter 11). In addition, in the ninth stage of synchronous connection of each generator 8, the load switch (or interrupter) 13 is the low voltage side winding of the external voltage transformer 9, and the cycle power generation plant is composed of a plurality of generators 8, And the external voltage transformer 9 has a 341-wire structure, and each low voltage
When the generator 1 is connected to the winding, the cross current due to parallel operation between the generators 1 of the Mu system and the B system is minimized by the automatic voltage regulator of each generator 1 and the 9 cross current compensator. However, the load current of each low-voltage winding of the step-up transformer 9 changes due to fluctuations in the number of operating generators 8 and differences in self-electromotive voltage between the low-voltage windings due to fluctuations in output. Current will circulate inside the transformer 9. This is due to the parallel operation of the transformer 46g, and this circulating current has a phase difference of approximately 90 degrees with respect to the I electromotive force, and the 111' flow is delayed by 90 degrees on the side where the induced voltage is higher. The current flows to the lower side of the induced 11jL current by 90 degrees, causing a voltage rise. As a result, the induced voltage difference becomes zero, but the load sharing of each low-voltage winding fluctuates, and the winding with reduced output may have a partner wire, or the winding may be overloaded, disrupting the operation of the entire plant. It will happen.

The principle of generating the above-mentioned circulating current will be described below. Figure 3 shows the market price circuit of Figure 2, and the third
In the figure, the following equation holds true.

Using equation (1), each current is determined as follows.

In this equation (2), when the A system and the B system are operated at their rated values, ■, = vb - ■, so the load current Iae Ib of each low voltage side winding is expressed by the following equation.

Therefore, the following formula holds. (If the power is not set to satisfy the 4th equation, a single circuit current will flow to compensate for this. For example, the output of system A is at the rated level, and the output of system B is 10% If it decreases, there is a fee to reduce the output of system A by 10% in order to satisfy equation (4).

Next, the internal voltage aIs and the electromotive voltage ΔV are determined.

Figure 4 If some tliB yarn generators 11 and 8 are stopped,
Or, it shows an equivalent (b) path diagram when the output t- is decreased, and the following equation holds true in FIG.

Based on this equation (5), the induced voltage difference lv is expressed as the following equation.

In this equation (6), the step-up transformation I! Each reaction p of 9
y SuXh, X@, XbO relationship is general K %X
Since h < Xa mXh < B thread voltage Vbt- will be lowered 1 A
KtllilJl current ΔI without reducing system output.

If it is possible to make it smaller, then it becomes K.

Therefore, in a combined cycle power generation ground, if multiple generators are connected to two low voltages of a three-winding external voltage transformer and the output of each low voltage changes, each low voltage - The load sharing of the windings fluctuates,
It is essential to keep the circulating current to a small level in order to reduce the output and prevent the tightening of the round-wound partner from becoming overloaded.

And these mackerel are combined cycle generators tf and K1ft, and their purpose is to provide each low voltage @ of the main transformer.
? Tightening output? The induced voltage difference (Δ■) is reduced by reducing the output voltage of the corresponding generator group and increasing the voltage between each winding.
1! Can each winding be suppressed and prevented from overloading in a combined cycle power plant? The object of the present invention is to provide an l1iI11 device.

[Praise for invention]

In order to achieve the above hC objective, the present invention provides a combined cycle power generation ground in which a plurality of generators are connected to two low voltage windings of a three-turn configuration step-up transformer (King transformer tF) and operated in parallel. Detect the output of each generator above,
Based on this detected nine outputs, the induced voltage difference between the two low-voltage coils is calculated, and the output voltage of the generator is adjusted to make the induced voltage difference zero. Features.

FIG. 5, which will be explained with reference to FIG. 5, shows an example of the system configuration of a nine combined cycle power generation ground equipped with a control device according to the present invention, and in the same figure, the same parts as in FIG. .

In the figure, the generator 1 on the moving platform and m generators 8 are:
The step-up transformer 9 has a three-winding configuration and is connected via the low-voltage winding clamp and the BK load switch (or interrupter) 13, and is connected from the high-voltage side winding of the external voltage transformer 90 to the bulk bus 10 and the transmission line. Connect the wire and send out the power from the interrupter 11JIC◎t.
An automatic voltage regulator 14 that automatically controls the output voltage of each generator 8 and a galvanometric compensator 15 that suppresses galvanic current between each generator 1 are provided.Furthermore, each low voltage side of the external voltage transformer IIS is provided. The winding M and BK drive a detector 16 for detecting the output current and voltage of each generator 8, and a voltage setter #OR for comparing the two and automatic voltage adjustment DI- of each generator 8, It is constructed by providing a calculation @11 for calculating an output signal for voltage control.

Next, the operation of the control device of the present invention configured as described above will be explained. Now, between the respective total output currents Ia and Ib of the generator 8 connected to the low voltage coils @A and B of the step-up transformer 9, and the actances Xa and xb of the lower voltage side coils and B, ■If the relationship is chosen so that νI b= Xb/X@, the low voltage positive lines A and B
When each load current is equal to the current and Ib, as described above, the low voltage chain winding 111! The voltages v1 and vb of A and B become equal, and no current flows.

On the other hand, due to fluctuations in the number of operating generators 8 and fluctuations in their output, the negative #note accents of low voltage @ winding and B are I, /Ib
If the relationship ＝XbAC, can no longer be maintained, low pressure @Q
k1ml! When the voltages (■ and Vb) of B and B are equal, a difference in fermentation pressure occurs between windings -^ and 8, and a circulating current flows. And B's burden share is "a/■b=Xv'
According to this configuration, each low voltage side winding of the step-up transformer 9 and the number of operating units of the power generator +@g connected to B and the output thereof can be changed. Output of wire and B, clamp, load current 1. and Ib are detected by the detector 1σ, and based on this, the arithmetic unit 11 calculates the rated current I□ of each low voltage side winding M and B, the difference current between Ibn and O, and ΔI
Calculate b, and from this calculate the difference in the collar electromotive force V in equation (7) above.
(=X, ・Δ■, Xb・)Ib), and set this induced voltage difference ΔV to zero, that is, the detector ICK
The automatic voltage regulator 14 of the register 8 detects a value KS#S corresponding to the difference between the output voltage of the Marumi electric machine 8 and the above-mentioned induced voltage difference.
By setting and driving the voltage setting device 110B, step-up transformation! It is possible to freely change the number of operating generators 8 of each of the 19 low-pressure chain windings aIA and BKii and change their outputs.

In this way, multiple generators with step-up transformers with 8 or 3 windings can be used.
In a combined cycle power generation plant where two low-voltage sides of 1F (raw transformer) 9 - A and BK are connected and operated in parallel, the output of each of the above generators is detected by 91 gK, and the output output from S is Based on each of the above low voltage side winding rams,
The electromotive force difference Δ■ between B is calculated by the calculator 11, and the output voltage of the generator 8 is controlled by the automatic voltage-gk device 14 so as to make the cough induced voltage difference Δ■ zero. control f41
◎Therefore, a plurality of generators 8 in the combined cycle power generation ground are connected to the two low-voltage windings of the step-up transformer 9 with the three-winding configuration and the BK
When connected and operated, it is possible to change the number of operating generators 8 and to reduce the induced voltage difference to zero due to the change.4!1 for each volume. By suppressing the circulating current between A and 8, overloading of each winding A and B can be reliably prevented, and the number of operating generators 8 and the output can be easily changed.

[Effect of Akimei]

As explained above, according to the present invention, the reduction in the output of each low-voltage side connection of the main transformer 6 is offset by the voltage difference (ΔV
) Control of an extremely reliable combined cycle power generation plant that can suppress the ring current of each winding by increasing the output voltage of the corresponding generator group by one step, thereby reliably preventing overloading of each winding for 6 hours. Equipment can be provided.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an example of the system configuration of a combined cycle power generation plant, Fig. 2 is a single line diagram showing the main circuit of the generator, and Fig. 3g and Fig. 4 are diagrams showing the power circuit according to the impedance of Fig. 2. , FIG. 5 is a configuration diagram showing an embodiment of a control device according to the present invention. DESCRIPTION OF SYMBOLS 1... Air compressor, 2... Combustor, 3... Bus turbine, 4... Gain, 5... Steam mapin, 6...
... Condenser, 1... Pump, 8... Generator, 9...
・Step-up transformer, 10... Collective main bus, 11... Power transmission-use interrupter, 12... Station transformer, 13... Load switch (t-hashi interrupt, J4...・Automatic voltage regulator,
15...Cross current compensator, 16...Detector, 17...
・Performance Xa.

Claims (1)

[Claims] The number of generators is divided into two groups, and the generators in each group are connected to the two low voltage windings of the external voltage transformer (main transformer) of the 3% edge structure and operated in parallel. At the combined cycle power generation ground, the output of 11 generators was detected,
Based on the detected output, the induced voltage difference f between each of the low-voltage dense windings is calculated, and the output voltage of the power generation image on the cutter is controlled so as to make the induced voltage difference zero. A control device for a combined cycle power generation gland that uses % images.