JPH0559902A - Load limiter following device, control method therefor and power generating system - Google Patents

Abstract

PURPOSE:To provide a load limiter following device, a control method therefor and a power generating system capable of securing a rated load even if a turbine extraction steam amount is changed. CONSTITUTION:A turbine extraction steam flow rate detector 21 detects a flow rate of steam extracted from a turbine to the exterior, to input a detection signal into a correction value function generator 18, which inputs a load limiter upper limit correction signal into a calculator 17 on the basis of the detection signal output from the turbine extraction steam flow rate detector 21. The calculator 17 takes therein a correction signal output from the correction value function generator 18 and a set signal output from a load limiter position upper limit setter 14, to set an upper limit of a load limiter on the basis of the signals so as to input the result into a low selector 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load limiter tracking device, a control method therefor, and a power generation system suitable for maintaining the rated load of a turbine when the amount of extracted gas from the turbine changes from gas burning to heavy oil burning.

[0002]

2. Description of the Related Art Generally, in a thermal power or nuclear power generation system, as shown in FIG. 5, a turbine 2 having a generator 1 and a boiler 4 are connected, and a regulator valve 3 is arranged between them.

The regulator valve 3 controls the flow rate of main steam flowing from the boiler 4 into the turbine 2, and is connected to the load limiter 5 and the governor 8 via a cam mechanism and a hydraulic mechanism.

The load limiter 5 is driven by a load limiter motor 6, and the position at that time is detected by a load limiter position detector 7. The governor 8 is the governor motor 9
The governor position detector 10 detects the position at that time.

The above-described power generation system is provided with a load limiter tracking device 11 for automatically tracking the position of the load limiter 5 by allowing the opening degree of the regulator valve 3 driven by the governor 8 to have an arbitrary fixed width. .. Then, the load limiter tracking device 1
1, a load limiter tracking width setting device 12 and an adder 1
3, a load limiter position upper limit setter 14, a row selector 15, and a comparison detection amplifier 16 are built in. Here, the adder 13 adds the signal of an arbitrary fixed width from the load limiter following width setting device 12 to the detection signal from the governor position detector 10 to set the position of the load limiter 5.

The row selector 15 takes in signals from the adder 13 and the load limiter position upper limit setting unit 14,
The lower one of these is selected and output to the comparison and detection amplifier 16.

The comparison detection amplifier 16 includes a row selector 15
The load limiter motor 6 is driven so that the deviation is amplified by comparing the load limiter position setting signal from the load limiter position detector 7 with the detection signal from the load limiter position detector 7 and the load limiter position has a constant width with respect to the governor position. Output a signal. The above is disclosed in, for example, JP-A-60-3406.

[0008]

By the way, the output Pg of the turbine generator is expressed as follows: Pg = k · w · Δi where k: constant w: main steam flow rate (excluding turbine extraction flow rate) Δi: heat drop enthalpy And the heat drop enthalpy Δi depends on the condenser vacuum.

When the amount of extracted air from the turbine increases or decreases, it is necessary to change the main steam flow rate w'passing the regulator valve in order to keep the output Pg of the generator constant. Particularly in a mixed combustion plant, when gas burning is switched to heavy oil burning, the amount of extracted air increases due to heat retention of the fuel line, etc. Therefore, the governor motor must control the opening / closing valve to increase the main steam flow rate w ′. In this case, since the load limiter tracking device controls the load limiter to follow the governor motor position (adjustment valve opening) with a certain width, the upper limit limiter is applied and the certain width cannot be secured.

That is, when the turbine extraction amount increases,
The governor motor position tries to rise above the load limiter motor position, but the opening / closing of the regulator valve that was driven by the governor motor is limited by the load limiter motor such that the steam flow rate is equivalent to the rated load with a small turbine extraction amount. Since the valve opening is reached, the rated load cannot be secured due to insufficient main steam flow rate.

That is, the load limiter follow-up device uses the detection signals from the load limiter position detector and the governor position detector, and the load limiter follow-up width setting device and the load limiter position upper limit setting signal in the device to extract the turbine bleed air. When the turbine extraction amount changes, the main steam flow rate w and the control valve opening degree V are changed as shown in FIGS. 6 and 7 because the setting calculation is performed by converting the load when the rated load is the smallest.
C changes respectively.

When the turbine extraction amount increases by + ΔVC at a constant load, the main steam flow rate w needs to be + Δw to keep the load constant, and the governor must open the regulator valve opening CV + ΔCV. But,
When the load limiter upper limit setting LLM LIM is at the position shown in the figure, the adjustment valve opening CV changes to A-C-D without changing from A-C-B due to the load limiter upper limit, and ΔC
There is a shortage of V ₀ . Therefore, there is a problem that the main steam flow rate w also lacks Δw ₀ and the rated load cannot be secured.

The object of the present invention is made in view of the above circumstances, and a load limiter tracking device, a control method therefor, and a power generation system capable of ensuring a rated load even if the turbine extraction amount changes. The purpose is to provide.

[0014]

A load limiter tracking device according to a first aspect of the present invention is a governor position detector for detecting a position of a governor for adjusting an opening degree of a control valve for adjusting a main steam flow rate to be supplied to a turbine. Is connected to the load limiter tracking device that automatically controls the load limiter position by a load limiter position setting signal that is obtained by adding a signal of an arbitrary fixed width to the detection signal from the governor position detector. It is characterized by having a correction means for correcting the upper limit of the setting signal based on the amount of change in the turbine extraction amount.

A load limiter tracking device according to claim 2 is
The correction means is characterized in that the upper limit of the load limiter position setting signal is corrected in proportion to the amount of change in the turbine extraction amount.

A load limiter tracking device according to claim 3 is
The correction means is an extraction flow rate detection means for detecting the flow rate of steam extracted from the turbine to the outside, and a correction function generating a correction signal for correcting the upper limit of the load limiter position setting signal based on the detection output of the extraction flow rate detection means. Means and an arithmetic means for taking in the setting signal output from the setting means for setting the upper limit position of the load limiter and the correction signal output from the correction function generating means, and adding both.

The load limiter tracking device according to claim 4 is
The correction function generating means is characterized by generating a correction signal for correcting the upper limit of the load limiter position setting signal based on the detection output of the extraction flow rate detection means in proportion to the amount of change in the turbine extraction amount.

According to a fifth aspect of the power generation system, the load limiter tracking device according to the first aspect is connected to a regulator valve provided between the boiler and the turbine for adjusting the main steam flow rate to be supplied to the turbine. The load limiter tracking device controls the opening / closing of the valve.

According to a sixth aspect of the control method of the load limiter follow-up device of the present invention, the position detection signal of the governor for adjusting the opening degree of the regulator valve for adjusting the flow rate of the main steam supplied to the turbine is set to a signal of an arbitrary constant width. In addition to generating a load limiter position setting signal that performs addition to set the position of the load limiter, the load limiter position setting signal automatically controls the position of the load limiter. It is characterized in that the upper limit value of the load limiter position setting signal is corrected when the amount changes.

According to a seventh aspect of the present invention, there is provided a method for controlling a load limiter tracking device, wherein when the turbine extraction amount changes, the upper limit value of the load limiter position setting signal for setting the position of the load limiter is changed to the turbine extraction amount. It is characterized in that it is corrected in proportion to the amount.

[0021]

In the load limiter follow-up device or the power generation system having the above structure, the upper limit of the load limiter position setting signal is raised when the operation of the boiler is changed from gas burning to heavy oil burning. As a result, the main steam flow rate that matches the rated load can be maintained.

The same effect can be obtained in the control method of the load limiter tracking device having the above configuration.

[0023]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of an embodiment of a power generation system to which the load limiter tracking device according to the present invention is applied. As shown in the figure, the characteristic part of the present invention is that the load limiter tracking device 11 includes a calculator 17 and a correction value function generator 18.
Is provided and the correction value function generator 18 is connected to the turbine extraction air flow rate detector 21, and other configurations are similar to those of the conventional example shown in FIG.

In the above structure, the turbine extraction flow rate detector 21 detects the flow rate of steam extracted from the turbine to the outside, and outputs the detection signal to the correction value function generator 18.

The correction value function generator 18 outputs a load limiter upper limit correction signal to the calculator 17 based on the detection signal from the turbine extraction flow rate detector 21.

Further, the computing unit 17 takes in the correction signal from the correction value function generator 18 and the setting signal from the load limiter position upper limit setting unit 14, and sets the load limiter upper limit based on these signals, The result is output to the row selector 15. In this embodiment, the arithmetic unit 1
7, the correction value function generator 18 and the turbine extraction air flow rate detector 21 constitute a correction means.

According to the load limiter follow-up device having the above-mentioned configuration, the load limiter upper limit can be set according to the change in the turbine extraction air flow rate. The principle will be described below.

FIG. 2 is a characteristic diagram of the load limiter upper limit setting correction characteristic with respect to the turbine extraction flow rate. When the turbine extraction amount is the minimum (NVC), the correction value is fixed to 0 and set.
When the turbine extraction flow rate changes by + ΔVC, the correction value is +
ΔMW, and by increasing the load limiter upper limit setting by the amount of + ΔMW, the main steam flow rate w and the control valve opening CV with respect to the turbine extraction flow rate are shown in FIGS. 3 and 4, respectively.
It changes as shown in. That is, when the turbine extraction flow rate changes from NVC to + ΔVC, the control valve opening CV corresponding to the rated load changes to AB, so the main steam flow rate w
Will flow by increasing by + Δw. In other words, even if the turbine extraction flow rate changes, it is possible to ensure the follow-up width up to the rated load of the generator.

[0030]

As described above, according to the present invention, the upper limit of the load limiter position setting signal is corrected on the basis of the change amount of the turbine extraction flow rate, so that the boiler is switched from gas-fired to heavy oil. Even if the operation is changed to fire, etc., it is possible to secure the main steam flow rate commensurate with the rated load of the turbine generator.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a power generation system to which a load limiter tracking device according to the present invention is applied.

FIG. 2 is a characteristic diagram showing a load limiter upper limit setting correction characteristic with respect to a turbine extraction flow rate of the load limiter tracking device shown in FIG.

FIG. 3 is a characteristic diagram showing a relationship between a main steam flow rate and a turbine extraction flow rate of the load limiter tracking device shown in FIG.

FIG. 4 is a characteristic diagram showing a relationship between a turbine valve extraction flow rate and a control valve opening degree of the load limiter tracking device shown in FIG. 1.

FIG. 5 is a configuration diagram showing a power generation system in which a conventional load limiter tracking device is installed.

FIG. 6 is a characteristic diagram showing the relationship between the main steam flow rate and the turbine extraction flow rate in the conventional load limiter tracking device.

FIG. 7 is a characteristic diagram showing a relationship between a turbine valve extraction flow rate and a control valve opening degree in a conventional load limiter tracking device.

[Explanation of symbols]

 1 Generator 2 Turbine 3 Control Valve 4 Boiler 5 Load Limiter 6 Load Limiter Motor 7 Load Limiter Position Detector 8 Governor 9 Governor Motor 10 Governor Position Detector 11 Load Limiter Tracking Device 12 Load Limiter Tracking Width Setter 13 Adder 14 Load Limiter position upper limit setting device 15 Low selector 16 Comparison detection amplifier 17 Computing device 18 Correction function generator 21 Turbine extraction flow detector

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kanta Suzuki 5-2-1 Omika-cho, Hitachi City, Ibaraki Prefecture Hitachi Ltd. Omika Plant

Claims (7)

[Claims] 1. A governor position detector that detects the position of a governor that adjusts the opening degree of a regulator valve that adjusts the flow rate of main steam supplied to a turbine is connected, and a detection signal from the governor position detector is set to an arbitrary constant value. In the load limiter tracking device that automatically controls the position of the load limiter by the load limiter position setting signal added with the width signal, the upper limit of the load limiter position setting signal is based on the change amount of the turbine extraction amount. A load limiter tracking device having a correction means for correcting. 2. The load limiter tracking device according to claim 1, wherein the correction unit corrects an upper limit of the load limiter position setting signal in proportion to a change amount of a turbine extraction amount. 3. The correction means corrects the upper limit of the load limiter position setting signal based on the extraction flow rate detection means for detecting the flow rate of steam extracted from the turbine to the outside and the detection output of the extraction flow rate detection means. A correction function generating means for generating a correction signal and a calculation means for taking in a setting signal output from a setting means for setting an upper limit position of the load limiter and a correction signal output from the correction function generating means and adding both The load limiter tracking device according to claim 1, further comprising: 4. The correction function generating means generates a correction signal for correcting the upper limit of the load limiter position setting signal in proportion to the change amount of the turbine extraction amount based on the detection output of the extraction flow rate detecting means. The load limiter tracking device according to claim 3. 5. The load limiter tracking device according to claim 1, wherein the load limiter tracking device is connected to a regulator valve provided between a boiler and a turbine for adjusting a main steam flow rate to be supplied to the turbine. A power generation system characterized by controlling the opening / closing of a control valve. 6. A load limiter position setting for setting a position of the load limiter by adding a signal of an arbitrary fixed width to a position detection signal of a governor for adjusting an opening degree of a regulator valve for adjusting a main steam flow rate supplied to a turbine. Generate a signal,
In a control method of a load limiter tracking device that automatically controls the position of the load limiter by the load limiter position setting signal, when the turbine extraction amount changes, the upper limit value of the load limiter position setting signal is corrected. A method for controlling a load limiter tracking device, comprising: 7. The load according to claim 6, wherein when the turbine extraction amount changes, the upper limit value of the load limiter position setting signal is corrected in proportion to the change amount of the turbine extraction amount. Limiter tracking device control method.