JPS6345815Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an improvement of a power generation amount control device for a steam turbine power generation facility that utilizes waste heat from, for example, an incineration facility.

[Technical background of the invention and its problems]

Power is supplied to multiple loads in municipal waste incineration facilities, etc. by connecting a generator G of a steam turbine power generation facility using waste heat from the incinerator and a commercial power source H in parallel, as shown in Figure 1. It was. In such a case, the power consumption (load power) ZP of all loads 1 to n is detected by the load power detector 11, and if it is larger than the generated power GP of the generator G, the power shortage is transferred to the commercial power supply H side. However, if the generated power GP on the generator G side becomes larger than that on the loads 1 to n, the excess power of the generator G will be supplied to the commercial power supply as shown by arrow A in Figure 1. A so-called reverse power transmission phenomenon occurs in which power flows to the power supply H side.

If the contract with the electric power company allows this reverse power transmission, the steam energy generated from waste heat can be fully utilized to generate electricity.
It also simplifies the operation and control of the power generation equipment, but if reverse power transmission is not permitted, the generator G
A limit value must be set for the generated power GP, and the power generation equipment must be controlled so that reverse power transmission does not occur under any circumstances.

Conventionally, in the case of such control, a predetermined limit value L is set for the generated power GP of the generator G as shown in FIG. How to prevent the voltage from exceeding ZP and load 1 from commercial power supply H as shown in Figure 3.
There is a method of controlling the power (received power) HP supplied to ~n to be constant.

However, even with the above control method, if the generated power GP of the generator G is operated at a value close to the load power ZP, a sudden decrease in the load power such as a plant trip (as shown in Figs. 2 and 3) ZQ)
However, the control response is delayed, resulting in temporary reverse power transmission. For example, received power
The fourth example uses the case where HP is limited as a constant.
To explain with reference to the figure, the difference between the load power ZP and the generated power GP becomes the received power HP. Therefore, if there is a control delay, when the load power ZP drastically decreases ZQ, the received power HP will not be controlled to the received power set value HS, and the power will be reversely transmitted P.

Therefore, in a control method that sets a limit value L, the level of this limit value L is lowered, and in a control method that keeps the received power HP from the commercial power source H constant, the set value of the received power HP is increased. Even if there is a sufficient amount of steam that can be generated, the generated power GP must be suppressed. As a result, expensive commercial power must be purchased from the electric power company, and surplus steam energy that is not used for power generation must be used to condense water in a condenser, which is a wasteful operation.

[Purpose of invention]

This invention was made based on the above circumstances,
The purpose is to provide a power generation amount control device that can prevent reverse power transmission when load power suddenly decreases and can minimize received power from a commercial power source.

[Summary of the idea]

The present invention includes a load power detector that detects the power of a load of a facility that receives generated power obtained by rotating a steam turbine using the waste heat of the facility, and a distribution line that compensates for the shortage of the generated power. When the load power decreases, a correction signal is generated to increase the decrease in load power, and when the load power increases, a correction signal is generated in the direction to delay the increase. A correction signal is created, and the feedback control section calculates the proportional value based on the deviation between this correction signal and the set value of the received power.
This is a power generation amount control device that performs an integral calculation and outputs an operation signal to a valve that controls the amount of steam to the steam turbine to control the generated power.

[Example of idea]

Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 5 to 7. FIG. 5 is an overall configuration diagram when the power generation amount control device according to the present invention is applied to a municipal waste incineration facility when the received power is controlled to be constant. In the figure, a generated power detector 10 detects the generated power GP of a generator G that generates power by being given rotational force by a steam turbine T, and a load power detector 11 detects the generated power GP of a generator G that generates power by being given rotational force by a steam turbine T. This is to detect the load power at. The load power signal from the load power detector 11 is configured to be sent to the mixer 12 through the correction calculation section 20.

The correction calculation unit 20 has a unidirectional incomplete differential characteristic, and specifically includes a lead calculation unit 21 and an absolute value calculation unit 22. The advance calculation unit 21 calculates the transfer function T1・S/(1+T2・
S) and the load power signal P1 as shown in FIG. 6b.
is converted into an incompletely differentiated waveform such as signal P2 and output. Here, T1 and T2 indicate the differential gain and delay time, and the load power signal P1
This is a parameter that determines the degree of change and reduction time of the signal P2 with respect to the change in the signal P2. Further, S is a Laplace operator. The absolute value calculation unit 22 converts the signal P2 from the advance calculation unit 21 into a positive value signal P3 as shown in FIG. 6b. mixer 23
is a signal obtained by subtracting the output signal P3 of the auxiliary calculation section 20 from the load power signal P1 directly input to the load power detector 11, and sends the signal as the load power correction signal P4 to the mixer 12. Received power HP from load power correction signal P4 of mixer 23
A signal obtained by subtracting the setting signal of the received power setting device 13 that sets the received power is sent to the feedback control section 14 as the generated power target value signal P5 to be supplied to the load.

The feedback control unit 14 controls the steam turbine T so that the target value and the actual generated power match based on the deviation value obtained by subtracting the generated power signal P6 of the generated power detector 10 from the generated power target value signal P5.
It outputs an operation signal P7 to a steam control valve 15 that controls the amount of steam flowing into the pump, and is composed of a mixer 14a and a proportional/integral (P1) calculation section 14b. The mixer 14a sends a deviation signal P8 obtained by subtracting the generated power signal P6 from the generated power target value signal P5 from the mixer 12 to the proportional/integral calculation section 14b.
Proportional and integral calculations are performed on the deviation signal P8 from a to obtain the operation signal P7.

Next, the operation of the apparatus configured as described above will be explained. When the municipal waste incineration facility is operated, the generated power detector 10 detects the generated power GP of the generator G, and the load power detector 11 detects the load power ZP. Therefore, the load power signal P1 from the load power detector 11 is converted into an incompletely differentiated waveform by the advance calculation unit 21 of the correction calculation unit 20, and this waveform passes through the absolute value calculation unit 22, so that it becomes as shown in FIG. 6c. mixer 2 with a waveform
Sent to 3. Therefore, the mixer 23 outputs a signal obtained by subtracting the signal P3 from the absolute value calculation unit 22 from the load power signal P1 (ZP) shown in FIG. 7, that is, when the load power ZP decreases as shown in FIG. When the load power ZP decreases, and conversely, when the load power ZP increases,
A load power correction signal P4 compensated for slowing down the increase speed is sent to the mixer 12. This load power correction signal P4 is subtracted by the set value HS of the received power HP in the mixer 12, and the resulting signal is sent to the feedback control section 14 as the generated power target value signal P5. In this feedback control section 14, the deviation between the generated power target value signal P5 and the generated power signal P6 is determined by the mixer 14a, and the deviation signal P8 is sent to the proportional/integral calculation section 14b. The proportional/integral calculation section 14b performs proportional/integral calculations on the deviation signal P8 so that the deviation signal P8 is zero, that is, the generated power target value signal P5 and the generated power signal P6 match, and the operation signal P7 is output to the steam control valve 15. Thereby, the steam control valve 15 is operated, and if the generated power GP is smaller than the generated power target value, the amount of steam to the steam turbine T is increased, and conversely, if the generated power GP is larger, the amount of steam is decreased. As a result, the generated power GP of the generator G is controlled to be smaller than the load power ZP, that is, the received power HP is controlled to be constant.

In this way, in this device, the load power signal P
1 is made into an incomplete differential waveform by the advance calculation unit 21 of the correction calculation unit 20, and is sent to the mixer 23 through the absolute value calculation unit 22, and from the mixer 23, the load power signal is sent in the direction of further decreasing when the load power signal decreases. In addition, when the load power increases, it is output as a load power correction signal P4 corrected to delay the increase, and the deviation between this correction signal P4 and the received power set value signal is output as the generated power target value signal P5 of the feedback control unit 14.
Therefore, when the load power ZP suddenly decreases,
This compensates for control delays, and as shown in FIG. 7, both the magnitude and time of reverse power transmission can be reduced. On the other hand, when the load power ZP increases, the load power correction signal P4 from the mixer 23 has a delay characteristic, resulting in a large change on the power receiving side, but this change on the power receiving side is a fail-safe side for municipal waste incineration equipment. It does not cause any trouble to the driver. Here, if a leading characteristic is used even when increasing, a change on the reverse power transmission side will also occur in the response, making it impossible to reduce the received power set value HS.

In addition, as mentioned above, when the load power ZP suddenly decreases, the magnitude of the reverse power transmission can be suppressed to a very small amount, so the received power set value HS can be reduced to a small value, and this allows the use of surplus steam energy. Efficiency can be improved and equipment can be operated more economically than conventional systems.

Note that the present invention is not limited to the above embodiment. In the embodiment described above, the correction calculation section 20 has the configuration of the advance calculation section 21 and the absolute value calculation section 22, but it may have the following configuration. First, the correction calculation unit 30 shown in FIG. 8 has separate calculation units 31 and 3 when the load power decreases and when the load power increases.
2 to obtain a load power correction signal.
The lead-lag calculation unit 31 for decreasing change has a transfer function (1
+T1・S)/(1+T2・S), and outputs a load power correction signal that advances the direction of decrease when the load power decreases.・S)/(1
+T4·S), and outputs a load power correction signal in the direction of delaying the increase in load power when it increases. The load power correction signal 33 from these calculation units 31 and 32 is sent to the calculation unit 31 when the change polarity determination unit 34 switches the switch S.
Therefore, when there is an increase, the calculation unit 32 outputs the output. It goes without saying that even with this configuration, reverse power transmission can be prevented when the load power suddenly decreases, but in this case, the characteristics of the calculation units 31 and 32 are set separately for when the load power decreases and when it increases. There are advantages that can be achieved.

Next, a correction calculation unit 40 shown in FIG. 9 is provided with a high limiter 41 in place of the absolute value calculation unit 22 in the above embodiment, and by setting the high limiter 41 to zero, the characteristics at the time of increase are corrected. It is assumed that the load power signal is not In this correction calculation unit 40, the delay at the time of increase is large;
It is effective in cases where it becomes a problem.

Furthermore, even if the correction calculation unit 50 is provided for feedback control of directly received power, this device can prevent reverse power transmission due to a sudden decrease in load power.
FIG. 10 is a configuration diagram when a correction calculation section 50 is provided in the received power feedback control system. The generated power signal from the received power detector 60 is sent to the correction calculation section 50. This correction calculation section 50 is
It is composed of a lead calculation section 51, an absolute value calculation section 52, and a mixer 53, which have a transfer function of T1・S)/(1+T2・S), and have the same directionality as in the above embodiment for the generated power signal. The corrected signal is output to the feedback control section 61. The feedback control section 61 uses a mixer 62 to determine the deviation between the correction signal and the generated power setting signal from the received power setting device 63, and based on this deviation signal, a proportional/integral calculation section 64 performs a proportional/integral calculation. An operation signal that makes the deviation signal zero is output to the steam control valve 65. In this way, even if the correction calculation section 50 is provided in the feedback system for received power, reverse power transmission due to a sudden decrease in load power can be prevented.

Further, the advance calculation unit 21 in the above embodiment,
The absolute value calculation section 22, the received power setting device 13, and the proportional/integral calculation section 14b may be configured by using software equipment such as a computer and performing calculations based on a program. Furthermore, the current may be detected instead of the load power, generated power, and received power, and control may be performed based on this detection signal.

[Effect of idea]

According to the present invention, the signals from the load power detector and the received power detector are corrected as correction signals in the correction calculation section, and based on the correction signals, the feedback control section performs proportional and integral calculations to generate the operation signal. Therefore, it is possible to provide a power generation amount control device that can prevent reverse power transmission when load power suddenly decreases and can minimize received power from a commercial power source.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram showing the power supply to the load in the waste incineration facility, Figures 2 and 3 are diagrams for explaining power control of the power generation equipment in Figure 1,
FIG. 4 is a diagram for explaining the reverse power transmission phenomenon in FIG. 1, FIG. 5 is a configuration diagram showing an embodiment of the power generation amount control device according to the present invention, and FIG. FIG. 7 is a diagram for explaining the operation of the present device, and FIGS. 8 to 10 are diagrams showing modifications of the present device. 10... Generated power detector, 11... Load power detector, 12... Mixer, 13... Received power setting device, 14... Feedback control section, 14a...
Mixer, 14b...Proportional/integral calculation section, 15...
Steam control valve, 20... Correction calculation section, 21... Advance calculation section, 22... Absolute value calculation section, T... Steam turbine, G... Generator.

Claims (1)

[Scope of claim for utility model registration] Power generation equipment that controls and supplies the power generated within the facility so that the sum of the received power and the power generated within the facility from waste heat equals the target value to the load within the facility. wherein the feedback controller is connected between a load power detector that detects power of the load or a received power detector that detects the received power, and receives a signal from the load power detector or the received power detector. a correction calculation unit that corrects the decrease in load power in a direction of increasing it when it decreases, and corrects it in the direction of delaying the increase when the load power increases; and this correction calculation unit makes correction based on a signal from the load power detector. When a signal is output, when the generated power target value which is the deviation between this correction signal and the received power set value is received, the generated power is proportionally calculated based on the deviation signal between this generated power target value and the generated power detected by the generated power detector. - When an integral calculation is performed and the correction calculation unit outputs a correction signal based on the signal from the received power detector, a proportional/integral calculation is performed based on a deviation signal between this correction signal and the received power setting value. A power generation amount control device, comprising: a feedback control section that controls the generated power.