JPS6275030A - Speed and load control device of prime mover for generator - Google Patents

Abstract

PURPOSE:To maintain the generated frequency of a generator stably, by provid ing a basic control circuit with which the generator can be operated at a basic speed adjusting fixed rate pattern and a upper limit side and a lower limit side control circuits with which the generator can be operated at a upper limit and a lower limit speed adjusting fixed rate patterns. CONSTITUTION:The speed and load control device of a gas turbine comprises three circuits. For example, a basic control circuit inputs the speed signal 1 and the 100% speed basis signal 2 of the gas turbine 15 into an additional point 3. A second upper limit side control circuit inputs the speed signal 1 and a 100.4% speed basis signal 24 into an additional point 23. A third lower limit side control circuit inputs the speed signal 1 and a 99.6% speed basis signal 29 into an additional point 28. When the speed signals exceed a fixed range, they are controlled by the upper and lower limit side control circuits. Thereby, the generated frequency can be maintained stably.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a speed/load control device for a generator or prime mover), particularly to a generator prime mover that is connected to a grid and operated without a governor. This invention relates to a suitable speed/load side control device.

[Background of the invention]

Conventional speed/load control devices for this type of generator J-ho machine have a constant speed regulation rate characteristic regardless of changes in load size, so in a relatively finite power grid, the frequency There was a problem in that it was not possible to obtain high-quality frequencies with a range of fluctuations. In addition, with conventional electric governors and speed regulators that adjust the regulation rate III, settings must be changed externally depending on the situation, and in electric governors with multi-stage regulation rate characteristics, there are steps in the regulation rate characteristics. In some cases, the frequency may drop by 1-11 or lower in steps, making it difficult to keep the range of frequency change small in response to rapid load fluctuations.

Incidentally, related devices of this type include, for example, Japanese Patent Publication No. 4fi-18203, Japanese Patent Publication No. 54130/1973,
Examples include Japanese Patent Publication No. 38-70281 and Japanese Patent Publication No. 6082-42.

[Purpose of the invention]

An object of the present invention is to provide a speed/load control device for a generator prime mover that can stably maintain the power generation frequency regardless of the load state.

[Summary of the invention]

The outline of the present invention is to operate according to a basic speed regulation rate pattern in a range where the frequency fluctuation width is small, in order to keep the frequency change lid in response to load fluctuations small in speed/load control with a speed regulation rate. In a range where the fluctuation width becomes large, the frequency change is suppressed by continuously shifting to an adjustment rate pattern smaller than the basic speed adjustment rate. In addition, the present invention adds an element to the element 1- above that switches to constant speed operation by setting the regulation rate to zero when the station is isolated due to an accident in the system, and even if the load within the station changes. It is equipped with multiple speed adjustments for one prime mover and heavy viscosity so that the rated frequency can be maintained.

The effects of the present invention are generally as follows.

When the speed regulation rate, which is the basic speed regulation rate of the prime mover, changes due to load fluctuation, the speed of the gas turbine increases or decreases according to the basic regulation rate, but by setting a limit point on this basic speed regulation rate characteristic pattern, this If the speed continues to increase or decrease beyond the limit point, a shift is made to another speed adjustment rate pattern with this limit point as the origin. The speed adjustment rate pattern having this limit point as the origin has a value smaller than the slope of the basic speed adjustment rate pattern. If the load fluctuation range is large and the speed change does not settle within the range of the basic speed regulation rate pattern and exceeds this limit point, the basic regulation rate characteristic will continuously shift to the smaller speed regulation rate, As a result, the value of the generator frequency characteristic constant increases, and speed fluctuations in response to load changes are suppressed. In addition, if the station is left alone, the power line breaker, which is the cause of the situation, will be disconnected! ), the input of the speed/load setting signal and the regulation rate setting signal of the Komoto speed regulation rate control circuit is 1111 t l, and only the two-man power addition of the prime mover speed signal and the reference speed signal is used to control the regulation type chamber, that is, constant velocity. I try to drive.

[Embodiments of the invention]

Hereinafter, embodiments of the present invention will be described based on the drawings, but before that explanation, in order to aid in understanding the present invention, we will explain the relationship between the output and frequency of the generators that are paralleled to the grid, that is, the generator frequency. The specific number K will be described in detail.

In general, generators connected to the power grid are operated in governor-free mode to ensure stable operation against load fluctuations, but the total output of the generators connected to the entire grid and the governor-free mode are different from each other. The frequency characteristic constant K of the system is determined in relation to the regulation rate of the generator prime mover.

This frequency characteristic constant is expressed by the following formula.

(i) In the case of one generator, Δl? li”Nδ Here, ΔP double electric machine output change Amount F: Amount of change in frequency PN Rated output of double electric machine FN: Generator rated frequency δ: Lower by the speed regulation rate of the generator prime mover. It is given by Eq.

o-FH δ= -X 100 (%) is called the transmission t11m frequency characteristic Kn of the system and is expressed by the F formula.

ΔF'j−lto"Ntδ1 Here, PN+: Rated output r" of i generator . Further, the larger the value of this characteristic Ko, the smaller the change in frequency with respect to load fluctuation. In the Daisai Nezumi strain, the value of this characteristic K t+ is very large, so some 0
Even if fluctuations occur in 4, the frequency remains stable without much fluctuation, but when the power grid becomes finite due to grid disconnection, etc., the value of this characteristic Ka decreases, and the range of frequency change with respect to fluctuations in zero load becomes smaller. It becomes difficult to stabilize the frequency with dog noises.

The embodiment of the present invention automatically reduces the regulation rate of the prime mover when the power grid becomes limited due to an accident or the like and the range of frequency changes due to load fluctuations becomes large.
This is an attempt to stabilize the frequency by increasing the value of the characteristic Ka described above, and will be explained below with reference to FIGS. 1 to 73.

FIG. 1 is a system diagram showing a speed/load control device for a gas turbine generator according to the present invention. The gas turbine power generation equipment includes a compressor 13, a gas turbine 15, and a generator 16. The generator 16 is connected to a power generation end bus 36 via a step-up transformer 17 and a generator breaker 18, and further connected to a main transformer 37 and a generator breaker 18. It is connected to an infinite string 39 via a power transmission line breaker 38.

The gas turbine speed/load control device is composed of three speed/load control circuits.

One of the speed/load control circuits in the ball is the basic speed/load control circuit, which controls the gas turbine speed (+
Q1 and a 100% speed reference signal 2 corresponding to the rated frequency are input to the addition point 3. In addition, in order to operate at a set rate, the speed/load setting signal 19 and the 4% speed setting car setting Np120
The debt is matched at the addition point 3X□3, and is inputted to the addition point 3 of the above-mentioned speed signal via the interlock contact 34. The interlock contact 34 is turned on when the power transmission line or disconnector is turned on.

The summing signal of summing point 3 is supplied to gas turbine fuel signal bus 6 via opposite sign operational amplifier 4 and low value selection (T, OW) value gate 5.

The second of the three speed/load control circuits is the upper limit speed/load control circuit, which also receives the gas turbine speed signal 1.
The 100.4% speed reference signal 24 corresponding to the 1-limit frequency, the speed/load setting signal 19, and the signal from the 2% speed adjustment rate setter 25 are input to the addition point 23, and this addition W(
The Ft signal is supplied to the gas turbine fuel signal bus 6 via an opposite sign operational amplifier 26 and an OW value gate 27.

The second lj lower speed/load control circuit of the three speed/load control circuits similarly receives the gas turbine speed signal 1 and the 99.6% speed reference signal 29 corresponding to the lower limit frequency. , the speed/load setting signal 19 and the 2% speed adjustment rate setter 30 are manually inputted to the addition point 28, and this addition signal is input to the gas through the opposite sign operational amplifiers 31S, R, and OW value gates 32. The turbine fuel signal bus 6 is supplied thereto.

The amount of fuel in the gas turbine is controlled so that the fuel flow rate is proportional to the potential of this fuel control signal gas 6. This fuel control signal 6 is finally supplied to a fuel control calculator 7, and the fuel flow rate is controlled by opening/closing a fuel flow bypass valve 9 in accordance with a signal 8 from this calculator 7. It's being adjusted. When the fuel flow bypass valve 9 is throttled down, the amount of bypass fuel (return fuel) sucked by the main fuel pump 11 is reduced, and the amount of fuel supplied to the gas turbine side is increased, so that the generator output is increased.

The following is the configuration of the gas turbine speed/load side control device according to the present invention.

Next, the operation of the embodiment of the present invention will be described.

It is assumed that the settings of each adjustment rate circuit in this embodiment are as follows in the 50 IIi system. .

(A) Reference speed/load control circuit reference speed signal = 100γ, (5(')II〆) adjustment rate:
4% (B), h eye side speed/load control circuit reference speed signal (
1, limit setting): l110.4% (5 (1, 2HX) Adjustment rate: 2% (C) Lower limit side speed/load control circuit reference speed signal (lower limit setting): 99.6% (49,8
11X) Regulation rate: 2% When the standard regulation rate is 4%, at the gas turbine rated speed (rated frequency), when the speed/load setting signal 19 is 100%, the generator output is 0%, and when the setting rate is 104%. The generator output should be 100%. In addition, 1.Limited adjustment rate 2% assumes that 100.4% of the rated speed is the apparent reference speed.

Furthermore, the lower limit adjustment rate of 2% is 99.6% of the rated speed as the reference speed of 1-. These adjustment rate characteristic curves are shown in FIG. In Figure 2, the Y-axis is the gas turbine speed (frequency), the X-axis is the generator output, and the
The diagonal line intersecting the axis indicates the speed regulation rate curve. To explain the operation of this embodiment, it is assumed that the generator is operated in parallel with the grid at 100% output, and that the output of the generator and the load are balanced. The frequency at this time is the rated 5oIt, and the characteristic curve L in FIG. 2 indicates operation at the PN point.

Under such operating conditions, the gas turbine speed and
Among the three speed/load control circuits of the load control device, the addition point 23 of the speed load control on the 22 side causes a deviation of (1-limit speed setting signal)> (gas turbine speed signal), and The output of the sign operational amplifier 26 is saturated at a positive potential. In addition, the addition point 28 of the lower limit side speed/load control causes a deviation of (lower limit speed setting signal) <(gas turbine speed signal), and the output of the opposite sign operational amplifier 31 in the final stage is saturated at a positive potential. ing. Therefore, these 1; limit and lower limit speed control circuits are L (') W value gate 27
32 is removed from the control system, and the speed and load control of the gas turbine is performed by the remaining basic speed and load control circuit. When the load on the grid decreases, the frequency of the grid increases by 1, i.e., the speed of the gas turbine increases by 1)
is 1. Seal. As a result, a positive deviation occurs in the input sum of the addition point 3 of the basic speed/load control circuit, and the output signal of the opposite-sign operational amplifier 4 becomes negative, and the potential of the fuel control signal bus 6 passes through the T and OW value gate 5. f becomes low, and the amount of fuel in the gas turbine is reduced.

Here, in order to provide a standard explanation, the following power network is assumed.

- It is assumed that the generator group connected to the grid has the same speed regulation rate as in the present invention.

-The generator frequency characteristic constant of the entire system is -500%.

・The system frequency is 501■z.

In such a power grid, if the load of the entire system is reduced by 50%, the frequency of the entire system is calculated from both equations as follows: Increases speed by 0.2%. This causes a positive deviation in the input sum of the addition point 3 of the basic speed/control circuit, and the output signal of the opposite-sign operational amplifier 4 becomes negative. quantity is reduced. Here, even if the load decreases, the speed
There is no change in this input signal level unless the load setting signal 19 is set to node i#1. Therefore, the decrease in fuel amount is determined by the sum of the speed/load setting signal 19 and the speed adjustment rate setting device 20;
and continues until there is no deviation in the sum of the gas turbine speed signal 1 and the 100% speed reference setter 2.

In other words, the output decreases along the 4% speed regulation rate curve shown in Figure 2, and the gas turbine speed increases to 100.2% (
50°I Hz), the mechanical power applied to the generator and the generator output equalize by 3V, and the sum of the inputs of the basic speed/load control circuit's W points: 3 becomes 1 zero. Gono NIZ
Since the generator output at the equilibrium point is 4% regulation rate, FNδ F)011XX0.04, that is, the system frequency is 0. IH〆I[ reduces the generator output to 95% and stabilizes the relationship between output and frequency.

When the load increases, the control is reversed.

In this way, the range of frequency fluctuation due to load fluctuation is determined by the generator frequency characteristic constant.

Next, due to an accident in the grid, the grid was separated due to power restrictions, etc., and the generator frequency characteristic constant K changed from 500% to 200%.
%. In such a downsized power grid, if the grid load is reduced by 60%, the overall system frequency will decrease by 0.3 IIX in frequency, 0.3 IIX in frequency and 0 in gas turbine speed.
．． 6 % F- Attempt to increase. This increases the gas turbine speed signal 1 and reduces the amount of fuel in the gas turbine as before. The speed of the gas turbine tries to rise to 100.6% (50,3Hz) along the basic regulation rate characteristic curve of 4%, but in the rising process the speed increases to 100.4%.
If this value is exceeded, speed/load control is applied to the upper limit side, and the potential of the output signal of the opposite sign operational amplifier 26 on the upper limit side becomes lower than the output signal of the opposite sign operational amplifier 4 of the basic speed/load control circuit. , ■, OW value gate 27 changes from basic adjustment rate control (4%) to upper limit adjustment rate control (2%
). As mentioned above, this speed/load control circuit with an upper limit of 2% regulation rate is 100.4% (5(')) of the turbine speed.
, 2Hz) as the apparent reference speed.

2) -f 210%, that is, 90% of the rating, is the apparent -L rated output. As a result, the generator frequency characteristic constant with an upper limit regulation rate of 2% becomes the following formula.

Pn'Fn' , the generator output of Appearance-F is as follows.

- Find the rated generator output P0 of the entire system using the generator frequency characteristic constant of the entire system with a 4% regulation rate.

P, =K -F, δ = 200% 50 Iz 4% = 40000[%] ・Therefore, the apparent generator output PIl' is
' = 0.9Pn =: 0,9 Due to the shift to a % regulation rate, the generator frequency characteristic constant increases from 200% to 359% when the regulation rate is 4%.

As explained at the beginning of the embodiment of the present invention, it was explained that the larger the value of K, the smaller the width of the frequency change, but the frequency Δf that finally settles due to the 60% reduction in the grid load as a result of this transition is as follows. become that way.

Δf=ΔF+ΔF′ where, ΔF: the frequency that changes on the 4% adjustment rate line (
Upper limit reference speed setting), Δ■): System load fluctuation, ΔF'I+': 2%, generator frequency characteristic constant in the regulation system system, K': 2' is the generator frequency in the regulation rate system According to the characteristic constant, α: apparent generator output conversion coefficient, 8f becomes K', and if the value is t4λ, then ko359 = 0.2 + 0.0 Fi =0.25 (11z) As a result, If the change in system frequency due to a 60% reduction in system load remains at 4%, it would be possible to suppress the change to 0.3Hz (11); 11. can be applied to the l-rise of
.

In the case of this iφ, if the grid load increases by 60%, the frequency will decrease by 0.3 TIz, but the frequency will decrease by 0.25.
can be kept to a minimum. The load fluctuation in this system is temporary, and if the load state returns to the state before the fluctuation as a process, for example, if the load that was reduced by 60% is added again to 60%, the frequency will decrease and the gas turbine generator will 2% at the beginning
The fuel control of the cast turbine is performed in the order of the regulation rate line and then the 4% regulation rate line, and the output and frequency are stabilized at the same point as before the fluctuation.

Next, when a generator is disconnected from the grid due to an accident in the grid, the station becomes isolated with its own in-house power as the load, but in general, when a generator suddenly becomes isolated, the load suddenly decreases. Since the speed of the gas turbine is suddenly shut down, the output of the gas turbine is abruptly reduced by the breaker disconnection signal to prevent an overspeed trip.

In this example, the gas turbine speed/load setting signal 19 is forcibly set to 100.3% by the breaker disconnection signal.

In the embodiment of the present invention, when the disconnection signal of the circuit breaker 38 connected to the grid is manually input, the circuit shown in FIG. The configuration is such that the addition signal 33 with the constant rate setting signal 20 is excluded by the interlock contact 34. Sunao) Chi, 1st
As shown in Figure 3 (Δ), the speed/load control circuit during in-house independent operation only requires two manual additions of the gas turbine speed signal 1 and 1 (10% reference signal 2), and changes from the regulation rate operation mode to constant speed operation. mode, and the other upper limit and upper limit speed/control circuits are excluded from control by r, 0w value gates 5.

The generator frequency characteristic constant when one unit is operated in such a constant speed operation mode (adjustment rate 0%) is as follows.

50) T×0 K is infinite, which means that the frequency does not change at all in response to load fluctuations.

FIG. 3 (B') shows a speed/load characteristic curve for constant speed operation control. 10% load when switching to one company in the school
, is assumed to be in equilibrium with the generator output at point P. When the station load: 35 decreases to 5%, the generator output is 10% for the load of 5%, so the gas turbine speed signal 1 increases only for the excess output.

As a result, a positive deviation occurs from the 10 ('1%) speed reference setting signal 2, and the output of the opposite-sign operational amplifier 4 becomes negative r, and the potential of the fuel control signal bus 6 decreases through the OW value gate 5. The fuel flow line is reduced.This continues until the point where the deviation between the two inputs is zero, ie the generator output is equal to the load at 5% (F)2. When the station load increases, the opposite is true, and the rated frequency is always obtained even if the station power fluctuates. The basic, upper limit, and lower limit adjustment rates of the present invention are all adjustable and can be set to arbitrary values. The operating characteristics of this example are shown in FIG.

FIG. 5 shows a circuit in which an upper or lower limiter is provided in the speed/load control device described above.

The difference from the circuit in FIG. 1 is that the limiter is, for example, 51. ．． 5Hz or 441rTx reference signal 401T
or r, the speed and load control signal I9, and the addition point 4111 or I, and the amplifier 42H or 1 that amplifies the deviation.
．． , r, ow value game 1-4314 or ■ are newly provided, and the upper limit side circuit and lower limit side circuit are omitted.

The operating characteristics of this circuit are shown in FIG. 8, which will be described later.

FIG. 6 shows that in the example of FIG. 1, the interval constant rate is 3%,
The speed/load characteristics are shown when the lower limit adjustment rate is set to 1%.

Figure 7 shows the example of Figure 1 with 1-interval constant rate of 2%
, shows the speed/load characteristics when the lower limit adjustment rate is set to 0%.

FIG. 8 shows the speed/load characteristics when the lower limit is set to a predetermined adjustment rate in the embodiment shown in FIG. 5.

According to an embodiment of the present invention, the fence 23 connected to the infinite NH line
) In the range where frequency fluctuations are small relative to load fluctuations, it is possible to operate at the conventional regulation rate of 4%; In this case, the adjustment rate can be switched without external operation, so even if frequent frequency fluctuations occur, the frequency can be suppressed to a stable frequency. Furthermore, even if the plant is operated alone, the rated frequency can be maintained without requiring any human operations. Furthermore, since the basic regulation rate, upper limit regulation rate, and lower limit regulation rate are each individually adjustable in relation to the generator frequency characteristic K of the power system, it is possible to flexibly respond to frequency stabilization of the entire system.

〔Effect of the invention〕

[1] As described above, according to the present invention, even in the event of a sudden accident that leads to a total outage accident mode due to a system accident, etc., the regulation rate of the generator prime mover can prevent the frequency from decreasing at the stage of the system frequency decreasing. The direction will be automatically switched.

Since the generator frequency characteristic constant K of the remaining limited power grid works to increase it, it is possible to prevent the spread of accidents due to a drop in the grid frequency, and also to prevent the frequency from suddenly increasing due to grid load disconnection etc. Since the adjustment rate is automatically switched in the same way, it is possible to compensate for transient frequency changes and suppress the increase to a level lower than that of the conventional method. Furthermore, according to the present invention, even if one generator is disconnected from the grid and becomes independent operation within the station, the rated frequency can always be obtained by switching to constant speed operation without being affected by load fluctuations. .

[Brief explanation of drawings]

Fig. 1 is a system diagram showing an embodiment of the speed/load control device for a gas turbine generator according to the present invention, Fig. 2 is a diagram showing the speed/load characteristic curve of the gas turbine generator, and Fig. 3 (A )
and (n) is a line diagram showing the circuit state and speed/load characteristic curve of the speed/load control device based on constant velocity operation control of the gas turbine generator, and Fig. 4 is a line showing the speed/load characteristic curve of Fig. 1. Fig. 5 is a system diagram showing another embodiment of the present invention, and Figs. 6 and 7 show the speed and load of the gas turbine generator when changing the speed regulation rate setting in the embodiment of Fig. 1. A diagram showing the characteristic curve, FIG. 8 is a diagram shown to explain the operation of FIG. 5. 1... Gas turbine speed signal, 2... 100% speed reference signal, 3... Reference side addition point, 4... Reference side opposite sign operational amplifier, 5... Reference side ■, OW value gate,
6...Fuel control signal bus, 7...Fuel control calculator,
8... Fuel supply signal, 9... Fuel flow bypass valve,
12... Fuel distributor, 13... Compressor, ]4.
... Combustor, 15... Gas turbine, 16... Generator, 17... Step-up transformer, 18... Generator breaker, 19... Speed/load setting signal, 20... Five Main adjustment rate setting signal, 23... Upper limit side addition point, 24... Upper limit side 100.4% speed reference signal, 25... Upper limit side adjustment rate setting signal, 26... 1; Eye side sign calculation Amplifier, 27...
・Upper limit side T, OW value gate, 28... Lower limit side addition point, 29... Lower limit side 99.6% speed reference signal, 30
...Lower limit side adjustment rate setting signal, 31...Lower limit side opposite sign operational amplifier, 32...Lower limit side T, OW value gate, 33 addition point, 34...Interlock contact, 3
5... Station load, 36... Generating end bus, 37... Main transformer, 38... Transmitting end breaker, 39... Infinite system.

Claims (1)

[Claims] 1. In a speed/load control device that has a speed regulating function in the prime mover for a generator and controls the speed regulating function, a basic speed used when the motor is operated in parallel with an infinite power system. It includes a basic control circuit that can operate with a regulation rate pattern, and an upper and lower limit side control circuit that provides a speed regulation rate pattern with smaller upper and lower limits outside the range of the basic speed pattern and can operate with that pattern. A prime mover for a generator, characterized in that the speed regulating function is controlled by a basic control circuit when the speed signal is within a certain range, and by an upper and lower limit control circuit when the speed signal exceeds a certain range. Speed/load control device. 2. The speed/load control device for a generator prime mover according to claim 1, wherein the upper and lower limit control circuit is provided with a limiter that allows operation at a constant speed above a constant speed signal. 3. The motor for a generator has a speed regulating function, and the speed/load control device that controls the speed regulating function is operated with the basic speed regulation rate pattern used when the generator is installed in parallel in an infinite power system. A basic control circuit that can set the speed regulation rate of the prime mover to zero, an upper and lower limit control circuit that can set upper and lower limit speed regulation rate patterns smaller than the above basic speed pattern outside the range of the basic speed pattern, and operate with that pattern. When the speed signal of the prime mover is within a certain range, the basic control circuit disconnects the generator from the grid, and when the speed signal exceeds the certain range, the upper and lower limit control circuit disconnects the generator from the grid. 1. A speed/load control device for a motor for a generator, characterized in that when the speed control function is controlled by the above-mentioned means.