JP4610717B2 - Gas turbine protection equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention detects a gas turbine (GT) intake air cooling system abnormality and protects the gas turbine.Protective deviceRelated.
[0002]
[Prior art]
The gas turbine has a characteristic that the turbine output decreases because the density of the intake air decreases when the atmospheric temperature increases. Therefore, in gas turbine power generation equipment, a system that increases the air density by cooling the intake air of the gas turbine with a coolant such as water as a measure to increase the power generation output during high temperature seasons when the atmospheric temperature is high, especially during peak power demand during the daytime ( Hereinafter, it is considered to compensate for a decrease in power generation output due to an increase in atmospheric temperature by an intake air cooling system).
[0003]
  The intake air is cooled and compressed by an air compressor and sent to a combustor. Fuel is supplied to the combustor through a fuel pressure control valve and a fuel flow rate control valve in order. Fuel burns in the combustorTheThe generated combustion gas rotates the turbine. In a gas turbine power generation facility, a generator is driven by a turbine. The exhaust heat energy is also recovered by supplying the exhaust gas of the turbine to a boiler or the like.
[0004]
The fuel flow rate is controlled by a fuel flow rate control valve. At that time, the fuel pressure control valve on the upstream side of the fuel flow rate control valve is proportional-integral (PI) controlled so that the differential pressure between the inlet and outlet of the fuel flow rate control valve becomes the set differential pressure.
[0005]
Fuel flow control includes load control, governor control, blade path temperature control, and exhaust gas temperature control.
[0006]
In load control, the opening of the fuel flow control valve is controlled by proportional integral (PI) control in accordance with a load such as a generator output.
[0007]
In governor control, the opening degree of the fuel flow control valve is controlled by proportional (P) control so that the rotational speed of the generator or the like is maintained at a predetermined speed.
[0008]
The blade path temperature control and the exhaust gas temperature control are temperature controls for preventing the turbine inlet gas temperature from exceeding a predetermined temperature (eg, 1350 ° C. in a large capacity gas turbine).
[0009]
In blade path temperature control, the exhaust gas temperature immediately after the final stage of the turbine (referred to as blade path temperature) is measured, and fuel is controlled by proportional integral (PI) control so that this becomes the set temperature (hereinafter referred to as blade path temperature set value). Control the flow rate.
[0010]
In exhaust gas temperature control, the exhaust gas temperature (simply called the exhaust gas temperature) in the exhaust duct downstream from the turbine final stage is measured, and proportional integration is performed so that this becomes the set temperature (hereinafter referred to as the exhaust gas temperature set value). (PI) Control the fuel flow rate.
[0011]
The blade path temperature set value is set as a value obtained by adding a bias value (hereinafter referred to as BPT bias) in consideration of the heat drop coming from the temperature measurement position to the exhaust gas temperature set value. The BPT bias is, for example, about several degrees Celsius to several tens of degrees Celsius.
[0012]
The opening of the fuel flow control valve is controlled by the smallest opening command among the opening commands in load control, governor control, blade path temperature control, and exhaust gas temperature control.
[0013]
At the partial load, the variable guide vanes of the air compressor are closed and controlled so that the turbine inlet gas temperature is as high as possible to improve the utilization efficiency of the exhaust heat energy.
[0014]
In this guide vane opening degree control, when the load is equal to or less than a predetermined load (predetermined partial load), the control line changes from the closed side to the full open according to the load, and when the load is equal to or greater than the predetermined load, the control line is always fully open. Is used. The predetermined load on the control line measures the intake air temperature at the inlet of the air compressor (the intake air temperature after cooling during operation of the intake air cooling system), and is shifted to the lower load side as the measured temperature is higher.
[0015]
On the other hand, as a run-back system for protecting the gas turbine, there is a system that gradually reduces the fuel flow rate so that the load gradually drops. Depending on the load drop rate, the normal load run-back (5% of the rated output of the gas turbine / Normal load change rate on the order of a minute rate) and rapid load runback (rapid load change rate on the order of 100% of the gas turbine rated output / minute rate) are known. In any runback, the opening of the fuel flow control valve is controlled by proportional integral (PI) control.
[0016]
[Problems to be solved by the invention]
During operation of the intake air cooling system, the load on the gas turbine is increased due to an increase in power generation output, etc.If an abnormality occurs in the intake air cooling system, the intake air temperature rises and the combustion gas temperature rises rapidly. There is a risk of malfunction and damage.
[0017]
Therefore, it is necessary to detect an abnormality in the intake air cooling system to prevent a sudden rise in the combustion gas temperature.
[0018]
In this case, it is conceivable to trip (stop) the gas turbine or disconnect the generator (load interruption). However, since power generation is not performed with this, it is not a good idea to consider that the main purpose of intake air cooling is a countermeasure for increasing power generation output in the high temperature season.
[0019]
Therefore, the first problem of the present invention is to reliably avoid a gas turbine failure without tripping (stopping) the gas turbine or disconnecting the generator (load shutoff) when the intake air cooling system is abnormal. It is. This can be achieved by reducing the fuel flow rate, and power generation can be continued.
[0020]
  In this case, when the refrigerant is water, the rise in the intake air temperature when the intake air cooling system is abnormal is, for example, about 5 ° C, so that it is a moderate load runback or a rapid load runback.NaThe load drop rate may be used.
[0021]
However, in the case of a refrigerant having a cooling effect higher than that of water, such as a gas liquefied gas, the intake gas temperature rises to several tens of degrees C when the intake air cooling system is abnormal.
[0022]
Therefore, the second problem of the present invention is to instantaneously reduce the fuel flow rate at a higher load drop rate than the rapid load runback so as to prevent an instantaneous sudden increase in the combustion gas temperature.
[0023]
In this case, since there is a control delay due to PI control of the fuel pressure control valve, it is necessary to significantly reduce the fuel flow rate in order to prevent a sudden rise in the combustion gas temperature. However, this is accompanied by a large load reduction, which leads to a significant decrease in power generation output.
[0024]
  Therefore, the third problem of the present invention is to minimize the load reduction when the fuel flow rate is reduced.sois there.
[0025]
Further, in the case of a partial load, if the fuel flow rate is reduced when the intake air cooling system is abnormal, the combustion gas temperature may temporarily rise.
[0026]
This is because the intake air temperature at the inlet of the air compressor rises at the same time as the load decreases due to a decrease in the fuel flow rate, but there is a response delay in the temperature sensor that measures this intake air temperature, until the measured value reaches the true intake air temperature. This is because the guide vanes are operated closer to the opening than when the intake air cooling system is abnormal due to the control of the closing and the combustion gas temperature rises.
[0027]
Accordingly, a fourth problem of the present invention is to prevent an increase in combustion gas temperature at a partial load accompanying a decrease in load due to a decrease in fuel flow rate.
[0028]
[Means for Solving the Problems]
  The configuration of the present invention for solving the above problems is as follows.
  An abnormality detection means for detecting an abnormality in the intake air cooling system of the gas turbine;
  Instantly change the gas turbine fuel flow rate when an abnormality is detected in the intake air cooling systemPreset fuel flow setEquipped with a means for instantaneously lowering the fuel flow rateAnd
The fuel flow rate instantaneous lowering means is
A governor set value instantaneous switching means for instantaneously switching a governor set value for controlling the rotational speed of the gas turbine from a current value to a preset governor set value lower than the present value;
A fuel pressure control valve opening advance setting means for setting the opening of the fuel pressure control valve in advance of the opening settling after the fuel amount is reduced when an abnormality is detected in the intake air cooling system;
Including a guide vane opening degree control means for maintaining the air vane opening degree of the air compressor at the opening degree at the time of abnormality detection or controlling it to the open side when the abnormality is detected in the intake air cooling system;
The abnormality detecting means is used when the pump to be operated for sending the refrigerant for intake air cooling stops, or when the deviation between the command value of the refrigerant flow rate and the actual refrigerant flow exceeds a preset deviation range, or actually Detects that the intake air cooling system is abnormal when the refrigerant flow rate of the refrigerant falls below the preset refrigerant flow rate value.
  It is characterized by that.
  In this case, the set fuel flow value is a load calculated as a function of the atmospheric temperature and is a value based on a load in which the turbine inlet temperature does not exceed a preset set temperature,
The governor set value is a value calculated as a function of the atmospheric temperature,
The abnormality detecting means detects that the gas turbine intake cooling system is abnormal when there are a plurality of pumps to be operated to send the intake cooling refrigerant and when two of the pumps stop simultaneously. .
[0037]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0038]
FIG. 1 shows an outline of the gas turbine power generation facility. In FIG. 1, 1 is a gas turbine intake chamber, 2 is an intake filter, 3 is an intake duct, 4 is an air compressor, 5 is a combustor, 6 is a fuel pressure control valve, 7 is a fuel flow control valve, and 8 is a turbine. , 9 is a generator, 10 is a refrigerant supply pipe, 11 is a pump, 12 is a refrigerant pipe, and 13 is a nozzle. The air compressor 4, the turbine 8, and the generator 9 are connected to each other.
[0039]
The air is taken into the intake chamber 1 through the intake air filter 2 at the inlet, compressed by the air compressor 4, and then sent to the combustion chamber 5 to burn the fuel. Fuel is supplied to the combustor 5 through a fuel pressure control valve 6 and a fuel flow rate control valve 7 in order. Combustion gas generated in the combustor 5 rotates the turbine 8, and the turbine 8 drives the generator 9.
[0040]
A coolant such as water is supplied to the pump 11 through the coolant supply pipe 10, pressurized by the pump 11, and sent to the intake chamber 1 through the coolant pipe 12. In the intake chamber 1, the refrigerant is sprayed from the nozzle 13 provided in the refrigerant pipe 12 to cool the intake air.
[0041]
The refrigerant flow rate (spray flow rate) is adjusted by a pump control device (not shown) according to a refrigerant flow rate command value given from a gas turbine control device (not shown).
[0042]
In FIG. 1, 14 is a gas turbine protection device, to which a pump stop sensor 15, a refrigerant flow rate sensor 16, an atmospheric temperature sensor 17, a differential pressure sensor 18, and an intake air temperature sensor 19 are connected.
[0043]
The gas turbine protection device 14 is connected to a fuel pressure control valve 6, a fuel flow rate control valve 7, and an actuator 20 that drives the variable guide vanes of the air compressor 4 to open and close.
[0044]
The pump stop sensor 15 is a sensor that detects the stop of the pump 11, the refrigerant flow rate sensor 16 is a sensor that detects an actual refrigerant flow rate (actual flow rate) flowing into or out of the pump 11, and the atmospheric temperature sensor 17 is an intake chamber. 1 is a sensor that detects the temperature of the air taken into the air compressor 1, and the intake air temperature sensor 19 is a sensor that detects the temperature of the air taken into the air compressor 4 (air that has been cooled during operation of the intake air cooling system). The pressure sensor 19 is a sensor that detects a differential pressure at the inlet / outlet of the fuel flow control valve 7.
[0045]
The gas turbine protection device 14 includes an intake air cooling system abnormality detection unit 21, an instantaneous fuel flow rate reduction unit 22, a fuel pressure control valve opening advance setting unit 23, and a guide vane opening control unit 24.
[0046]
FIG. 2 shows a configuration example of the intake air cooling system abnormality detection means 21. In this example, the output of the pump stop sensor 15, the output of the refrigerant flow rate sensor 16, and the command value of the refrigerant flow rate are used, and when the pump 11 is stopped or the deviation between the command value of the refrigerant flow rate and the actual flow rate is predetermined. When the range is exceeded, or when the actual flow rate of the refrigerant falls below a predetermined determination reference value, it is determined that the intake cooling system of the gas turbine is abnormal.
[0047]
As the pump stop sensor 15, a sensor that detects the stop of the pump 11 based on a decrease in the discharge pressure of the pump 11, a decrease in rotational speed, or a pump power supply off can be used.
[0048]
As the refrigerant flow sensor 16, a sensor that detects the actual refrigerant flow rate per unit time based on the flow rate in the refrigerant supply pipe 10, the discharge flow rate of the pump 11, the flow rate of the refrigerant pipe 12, or the like can be used.
[0049]
In the case of detecting an abnormality in the intake air cooling system based on the deviation between the command value of the refrigerant flow rate and the actual flow rate, in this example, the abnormality occurs when [refrigerant actual flow rate <refrigerant flow rate command value−any predetermined value] is satisfied. It is decided that there is. However, it may be determined that there is an abnormality even when [refrigerant actual flow rate> refrigerant flow rate command value + arbitrary predetermined value].
[0050]
As shown in FIG. 3, in the intake air cooling system including a plurality of pumps 11, the refrigerant is supplied to each pump 11 through a common refrigerant supply pipe 10 and is pressurized by each pump 11 and connected to each pump 11. The refrigerant is sent to the intake chamber 1 through the refrigerant pipe 12. In the intake chamber 1, the refrigerant is sprayed from the nozzles 13 provided in each refrigerant pipe 12. In this case, adjustment of the refrigerant flow rate may be performed by controlling the number of operating pumps 11 in accordance with the refrigerant flow rate command value.
[0051]
When the intake air cooling system includes a plurality of pumps 11 as described above, it is determined that the intake air cooling system is abnormal when two or more of the pumps 11 to be operated stop simultaneously. May be. Thereby, the abnormality of the intake air cooling system can be reliably detected.
[0052]
When there are a plurality of pumps 11, the refrigerant flow rate sensor 16 is based on the flow rate in the common refrigerant supply pipe 10, the total discharge flow rate of all the pumps 11, the total flow rate of all the refrigerant pipes 12, or the like. It can be used to detect the actual refrigerant flow rate per hour.
[0053]
When the intake air cooling system abnormality detection means 21 determines that the intake air cooling system is abnormal, the intake back cooling system abnormality signal runback request 21a (signal state is “1”), the fuel flow instantaneous drop means 22, the fuel pressure adjustment This is given to the valve opening degree advance setting means 23 and the guide vane opening degree control means 24.
[0054]
FIG. 4 shows an example in which the governor control circuit is used as an example of the instantaneous fuel flow rate lowering means 22 and the governor set value is switched instantaneously. In FIG. 4, 25 is an AND circuit, 26 is a set reset circuit (a flop flop circuit, hereinafter referred to as an SR circuit), 27 is a single shot timer (hereinafter referred to as an SS circuit), 28 is a subtractor, 29 is a lower limit monitor, and 30 is a knot circuit. , 31 is a subtractor, 32 is a lower limit monitor, 33 is an AND circuit, 34 is a time timer, 35 is an OR circuit, 36 is a knot circuit, 37 is an adder, 38 is an analog signal generator for adjustment, 39 is an analog signal switch , 40 is a dummy analog signal generator, 41 is an analog memory, 42 is an adder, 43 is a subtractor, and 44 is a governor gain device (proportional controller).
[0055]
The AND circuit 25, the SR circuit (set reset circuit) 26, the subtractor 28, the lower limit monitor 29, and the knot circuit 30 generate a runback command 26a (signal state is “1”) when the intake air cooling system is abnormal.
[0056]
The subtractor 28 inputs an actual load signal 45 representing a generator output (corresponding to a turbine shaft output) that is an actual load and a runback permission load signal 46 representing a predetermined runback permission load, and the difference ( (Actual load-runback permission load) is obtained and output to the lower limit monitor 29. The lower limit monitor 29 gives the output to the knot circuit 30 as [0] when [actual load-runback permission load] is 0 or more and as "1" when it is less than 0.
[0057]
The AND circuit 25 inputs the runback request 21a when the intake air cooling system is abnormal and the output of the knot circuit 30, and when both are "1", the SR circuit 26 is set. When the SR circuit 26 is set, it outputs a runback command 26a.
[0058]
Accordingly, the runback command 26a is output when the intake air cooling system is abnormal and the actual load is greater than or equal to the runback allowable load. As will be described later, the runback command 26a is reset when the output of the OR circuit 35 becomes "1".
[0059]
When the runback command 26a is output, the governor control is “ON” and the load control is “OFF”.
[0060]
The governor set value is instantaneously switched by the runback command 26a and maintained for a predetermined period.
[0061]
This is achieved by the SS circuit (single shot timer) 27, the adder 37, the adjustment analog signal generator 38, the analog signal switch 39, the dummy analog signal generator 40, and the analog memory 41.
[0062]
That is, when the runback command 26a is output, the SS circuit 27 is triggered, and the pulse signal 27a that becomes “1” for 0.2 seconds, for example, is output to the analog signal switch 39 and the analog memory 41.
[0063]
The adder 37 is an adjustment signal indicating an analog signal (hereinafter referred to as a “runback target signal”) 47 representing a runback target value (variable value in this example) in the governor setting and a negative adjustment value generated by the analog signal generator 38. An analog signal 38a is input, and a signal (hereinafter referred to as an adjusted runback target signal) 37a representing the sum (runback target value + adjustment value (negative value)) is output to the analog signal switch 39. Further, the analog signal generator 40 generates a dummy analog signal 40 a representing a value 0 and outputs it to the analog signal switch 39.
[0064]
The analog signal switch 39 is used for the dummy for which the value is 0 when the runback command 26a is not issued and the pulse signal 27a is "0" among the adjusted runback target signal 37a and the dummy analog signal 40a. When the signal 40a is output and the runback command 26a is issued, the output signal is instantaneously switched to the adjusted runback target signal 37a (its value is [runback target value + adjusted value]), and the pulse signal 27a is set to “1”. This is output while The output of the analog signal switch 39 is given to the analog memory 41.
[0065]
The time required for switching the output of the analog signal switch 39 is extremely short, and is less than milliseconds.
[0066]
Here, the adjustment analog signal 38a is used to finely adjust the runback target value, and is adjusted and fixed to an appropriate negative value when tuning a system such as a gas turbine power generation facility.
[0067]
The dummy analog signal 40a is provided simply because the analog signal switch 39 has a characteristic that it requires two inputs.
[0068]
Among the input signals from the load control follow-up signal 48 and the analog signal switching unit 39, the analog memory 41 is in the load control follow-up signal while the runback command 26a is not issued and the pulse signal 27a is "0". 48, when the runback command 26a is output, the output signal is instantaneously switched to the input signal from the analog signal switch 39 (specifically, only the adjusted runback target signal 37a), and the pulse signal 27a is "1". This is output while “ The output signal of the analog memory 41 represents the governor set value SPSET.
[0069]
The time required for switching the output of the analog memory 41 is also extremely short, being less than milliseconds.
[0070]
The load control follow-up signal 48 is a signal that is given to cause the governor control to automatically follow the load control during load control, and is, for example, about 105% of the load control signal.
[0071]
As described above, when the runback command 26a is issued, the output of the analog memory 41 is instantaneously switched from the load control follow-up signal 48 to the adjusted runback target signal 37a. Therefore, the governor set value SPSET is [runback target value + adjustment value]. For example, is held for 0.2 seconds.
[0072]
The fuel flow rate is controlled by the adder 42, the subtractor 43, and the governor gain device (proportional controller) 44 so that the rotational speed of the turbine becomes the rated speed.
[0073]
The adder 42 adds the rated speed bias signal 49 and the initial load bias signal 50 to the governor set value SPSET, and outputs the addition result to the subtractor 43.
[0074]
The subtracter 43 subtracts the rotational speed signal 51 representing the rotational speed of the turbine from the output signal of the adder 42 and outputs the result to a governor gain unit (proportional controller) 44.
[0075]
The governor gain unit 44 multiplies the input signal by a coefficient K and outputs the result as a governor control signal GVCSO.
[0076]
Therefore, in the governor control, the fuel flow rate adjusting valve 7 is normally opened and closed by proportional control so as to automatically follow the load control to maintain the turbine rotational speed at the rated speed, but the intake air cooling system is abnormal, and When the actual load is equal to or greater than the runback allowable load, the governor set value is instantaneously switched to [runback target value + adjustment value], and the fuel amount adjustment valve 7 is throttled by proportional control, for example, for 0.2 seconds, Reduce the load.
[0077]
In this case, in the governor control, the fuel flow rate control valve 7 is proportionally controlled, and the output switching time of the analog signal switch 39 and the analog memory 41 are both extremely short, so that the fuel flow rate decreases instantaneously.
[0078]
For example, the fuel flow rate can be sufficiently reduced at an ultrafast load change rate of 50% / 50 milliseconds (= 60000% / min rate) of the rated output of the gas turbine.
[0079]
As described above, when the gas turbine intake cooling system is abnormal, the fuel flow rate can be instantaneously reduced. Therefore, it is possible to prevent a gas turbine failure by suppressing a sudden rise in the combustion gas temperature and to continue power generation. it can.
[0080]
As shown in FIG. 5, the governor control signal GVCSO is input to the low selector 52.
[0081]
The low selector 52 selects the signal having the smallest value among the governor control signal GVCSO, the load control signal LDCSO, the blade path temperature control signal BPCSO, and the exhaust gas temperature control signal EXCSO, and uses this as the fuel flow control valve. 7 as an opening degree control signal CSO.
[0082]
FIG. 6 shows an example of a circuit for generating a runback target value in the governor setting. The circuit in this example includes a subtractor 53, a function generator 54, a subtractor 55, and a row selector 56.
[0083]
The subtractor 53 receives the signal 57 representing the actual driving output and the first predetermined value signal 58 representing the first predetermined value, obtains the difference (actual driving output-first predetermined value), Output to selector 56.
[0084]
The function generator 54 receives the atmospheric temperature signal 17a representing the atmospheric temperature detected by the atmospheric temperature sensor 17, and sets the maximum allowable load according to the atmospheric temperature within a range where the gas turbine inlet temperature does not exceed the predetermined rated temperature. The signal 54 a is calculated and output to the subtractor 55.
[0085]
The subtractor 48 inputs the maximum allowable load signal 54a corresponding to the atmospheric temperature and the second predetermined value signal 59 representing the second predetermined value, and the difference (maximum allowable load corresponding to the atmospheric temperature minus the second predetermined value). Value) and output to the row selector 56.
[0086]
The low selector 56 selects, from two input signals, a smaller value among [actual operation output—first predetermined value] and [maximum allowable load according to atmospheric temperature—second predetermined value]. Is the runback target value of the governor setting.
[0087]
For example, in a 300 MW class gas turbine power generation facility, the first predetermined value is 25 MW, and the second predetermined value is such that [maximum allowable load according to atmospheric temperature−second predetermined value] is around 210 MW. Value.
[0088]
Therefore, in this example, when the actual operation output is relatively large, for example, 210 MW or more, [the maximum allowable load according to the atmospheric temperature−second predetermined value] is set as the governor-set runback target value. When the operation output is relatively small, for example, less than 210 MW, [actual operation output-first predetermined value] is set as the runback target value in the governor setting.
[0089]
Next, an example of resetting the runback command 26a will be described. The resetting of the runback command 26a is achieved by the subtractor 31, the lower limit monitor 32, the AND circuit 33, the time limit timer 34, the OR circuit 35 and the knot circuit 36 in FIG.
[0090]
In FIG. 4, the subtractor 31 inputs the governor set value SPSET output from the analog memory 41 and the runback target value in the governor setting, obtains the difference (governor set value SPSET−runback target value), and sets the lower limit. Output to the monitor 32. The lower limit monitor 32 gives the output to the AND circuit 33 as “0” when [the governor set value SPSET−runback target value] is 0 or more, and as “1” when it is less than 0.
[0091]
In addition to the output of the lower limit monitor 32, the AND circuit 33 is supplied with a signal indicating that the actual flow rate of the refrigerant is not more than a specified value and the output of the lower limit monitor 29 (see the set of the runback command 26a described above). The
[0092]
The specified value here is a value for confirming that the actual flow rate of the refrigerant has sufficiently decreased after detecting the abnormality of the intake air cooling system.
[0093]
As described above, the lower limit monitor 29 sets the output to “0” when [actual load−runback permission load] is 0 or more, and to “1” when it is less than 0.
[0094]
In this case, the actual load becomes less than the runback permission load immediately after the runback command 26a (for example, in 0.2 seconds), and the governor set value SPSET also becomes equal to or greater than the runback target value immediately after the runback command 26a. Since the actual flow rate of the refrigerant becomes less than the specified value after a while after the runback command 26a, the output of the AND circuit 33 becomes "1" after a while.
[0095]
The output of the AND circuit 33 is output to the OR circuit 35 through a time timer 34 of 30 seconds, for example. The time timer 34 is used to allow time before the run-back command 26a is reset. For example, 30 seconds after the output of the AND circuit 33 becomes “1”, the output of the time timer 34 becomes “1”. become.
[0096]
The OR circuit 35 is given a signal that is "1" when the gas turbine is not in parallel with the generator, in other words, when the gas turbine is disconnected from the generator.EtIt is. This signal is obtained by passing through a knot circuit 36 a generator parallel signal 60 that is "1" when the generator is parallel to the gas turbine.
[0097]
The “1” output of the OR circuit 35 resets the SR circuit 26.
[0098]
As described above, the runback command 26a is output when the intake air cooling system is abnormal and the actual load is greater than or equal to the runback allowable load on the condition that the generator is arranged in parallel with the gas turbine. .
[0099]
Further, when the generator is disconnected from the gas turbine after the runback command 26a is output, or when the actual load is less than the runback permission load and the governor set value SPSET is the runback target value (adjustment). The runback command 26a is reset when the runback target value minus the adjustment value (negative value) is greater than or equal to and the actual refrigerant flow rate is less than or equal to the specified value.
[0100]
FIG. 7 shows a configuration example of the fuel pressure control valve opening advance setting means 23.
[0101]
In FIG. 7, 6 is a fuel pressure control valve, 7 is a fuel flow rate control valve, 18 is a differential pressure sensor, 61 is a subtractor, 62 is a proportional integral (PI) controller, and 63 is a single shot timer (hereinafter referred to as SS circuit). 64 are analog signal switchers, and 65 is a function generator. Reference numerals 66 to 68 denote analog signal generators, which respectively generate a fully closed analog opening signal, a decompression analog opening signal at the time of stopping, and an ignition analog opening signal. Reference numerals 69 to 70 denote analog signal switchers.
[0102]
The valve opening degree of the fuel flow rate adjusting valve 7 is controlled by a control signal CSO output from the low selector 52 shown in FIG.
[0103]
At that time, basically, the differential pressure between the inlet and outlet of the fuel flow control valve 7 is measured by the differential pressure sensor 18, and the fuel provided on the upstream side so that the measured value of the differential pressure matches the differential pressure set value. The PI controller 62 performs PI control on the opening degree of the pressure control valve 6. That is, the differential pressure measurement signal 18a and the differential pressure setting signal 71 are input to the subtractor 61, and the PI controller 62 controls the fuel pressure control valve so that the difference (differential pressure measurement value−differential pressure setting value) becomes zero. An opening degree command is given to 6 to perform opening degree control.
[0104]
Therefore, as indicated by broken lines in FIGS. 8A, 8B, and 8C, even if the governor set value is instantaneously switched to a low value and the fuel flow rate adjusting valve 7 is instantaneously throttled, the fuel pressure adjusting valve Since 6 is opened with a delay due to the PI control, the differential pressure of the fuel flow rate adjusting valve 7 decreases with a delay, so that the fuel flow rate decreases with a delay and the load decreases.
[0105]
When there is a control delay in opening and closing the fuel pressure control valve 6 as described above, in order to prevent a sudden rise in the combustion gas temperature, it is necessary to switch the governor set value to a significantly low value instantaneously to greatly reduce the fuel flow rate. is there. However, this is accompanied by a large load reduction 72, which leads to a significant decrease in power generation output.
[0106]
In this example, such a problem is solved by the PI controller 62, the SS circuit 63, the analog signal switch 64, and the function generator 65.
[0107]
The PI controller 62 used in this example includes an external signal input terminal 62a for inputting an analog opening signal from the outside, and an instantaneous switching of the opening command to a value corresponding to the analog opening signal from the outside. A control terminal 62b is provided. When the control terminal 62b is "1", the PI controller 62 does not perform the original PI operation, but instantaneously switches the opening degree command to a value corresponding to the analog opening signal from the outside.
[0108]
The SS circuit (single shot timer) 63 is triggered when the runback command 26a output from the SR circuit 26 of FIG. 4 becomes “1”, and is a pulse signal that becomes “1” only for a predetermined period of, for example, 3 seconds or less. 63a is generated and applied to the control terminal 62b of the PI controller 62 and the analog signal switch 64.
[0109]
The analog signal switch 64 switches between the output of the function generator 65 and the output of the analog signal switch 69 in accordance with the pulse signal 63a from the SS circuit 63, and applies it to the external signal input terminal 62a of the PI controller 62. Specifically, the output of the function generator 65 is given to the external signal input terminal 62a while the pulse signal 63a is “1”, and the output of the analog signal switch 69 is supplied to the external signal input terminal while it is “0”. Give to 62a.
[0110]
The function generator 65 inputs the valve opening degree control signal CSO for the fuel flow rate adjustment valve 7 output from the low selector 52 shown in FIG. 5, and is settled with respect to the control signal CSO based on a predetermined function. An analog settling opening degree signal 65 a indicating the opening degree of the fuel pressure control valve 6 is output to the analog signal switching unit 64.
[0111]
This function is determined in advance by experiments or the like.
[0112]
When the intake air cooling system is abnormal, the valve opening degree control signal CSO of the fuel flow control valve 7 becomes an opening degree (GVCSO) corresponding to the runback target value set in the governor, so that the analog settling generated by the function generator 65 is performed. The opening signal 65a represents the opening of the fuel pressure control valve 6 corresponding to the fuel flow control valve opening.
[0113]
  Therefore, as shown by the solid lines in FIGS. 8A, 8B, and 8C, the runback command 26a becomes "1".WhatWhen the governor set value is instantaneously switched to a low value and the fuel flow control valve 7 is instantaneously throttled, the fuel pressure control valve 6 is not PI-controlled. It will switch instantly to the opening that will be. That is, while the pulse signal 63a is “1”, the opening degree of the fuel pressure control valve 6 is set in advance of the opening degree that is settled after the fuel flow rate is lowered, and then PI control is performed. Eventually, the differential pressure of the fuel flow rate adjusting valve 7 remains constant, the fuel flow rate decreases instantaneously, and the load also decreases instantaneously. Therefore, a rapid increase in the combustion gas temperature can be reliably prevented with a small load reduction 73, and a decrease in the power generation output is reduced.
[0114]
An appropriate switching control signal (not shown) is provided to the analog switches 69 and 70, so that the fully closed analog opening signal 66 is displayed when fully closed, the depressurizing analog opening signal 67 is displayed when stopped, and the ignition opening signal 67 is used when ignited. The analog opening signal 68 is selected and applied to the external signal input terminal 62a of the PI controller 62.
[0115]
In these cases, since the runback command 26a is “0”, the PI controller 62 performs the PI operation based on the external signal.
[0116]
Next, FIG. 9 shows a configuration example of the guide vane opening degree control means 24.
[0117]
In FIG. 9, 20 is an actuator for driving a variable guide vane of an air compressor, 74 is an opening controller, 75 is a function generator, 76 is an adder, 77 is a function generator, and 78 is an analog signal switch.
[0118]
The opening controller 74 uses a guide vane opening control line as shown in FIG. 10 and corresponds to the actual load and the intake air temperature at the inlet of the air compressor (the intake air temperature after cooling during operation of the intake air cooling system). The actuator 20 is controlled so that the guide vane opening is set.
[0119]
Its basic purpose is to close and control the variable guide vanes of the air compressor at part load, thereby increasing the turbine inlet gas temperature and improving the utilization efficiency of exhaust heat energy.
[0120]
As described above, the guide vane opening control line changes from fully closed to fully open according to the load when the load is a predetermined load (predetermined partial load) or less, and is always fully open when the load is equal to or greater than the predetermined load. The predetermined load is shifted to the lower load side as the intake air temperature at the air compressor inlet is higher.
[0121]
Specifically, the function generator 75 receives an intake air temperature signal 19a representing the intake air temperature after cooling of the air compressor inlet measured by the intake air temperature sensor 19, and based on a predetermined function, a load shift amount (cooled) is generated. The predetermined load shift amount corresponding to the intake air temperature) is obtained and output to the adder 76. This function is predetermined by experiment or the like.
[0122]
The adder 76 receives the actual operation output signal 57 representing the actual load and the load shift signal 75a representing the load shift amount from the function generator 75, and the sum (actual load + load shift corresponding to the intake air temperature). A signal representing the quantity) is output to the function generator 77.
[0123]
The function generator 77 uses, as a guide vane opening degree control line, a guide vane opening degree signal 77a representing a guide vane opening degree corresponding to [actual load + load shift amount corresponding to intake air temperature] given from the adder 76. It is determined based on a corresponding predetermined function.
[0124]
However, if the guide vane opening degree signal 77a is directly supplied to the opening degree controller 74, as described above, the combustion gas temperature may temporarily rise due to the load reduction accompanying the fuel amount reduction when the intake air cooling system is abnormal. is there.
[0125]
That is, as shown in FIG. 10, when the guide vane is controlled to a certain opening degree 79 on the control line, if the load decreases due to the fuel flow rate decrease, the intake air temperature at the air compressor inlet increases at the same time. Since there is a response delay in the intake air temperature sensor 19 that measures the intake air temperature, the guide vane is closed until the measured value reaches the true intake air temperature, and the opening 79 of the intake air cooling system abnormal time is controlled by the user's control. Is also operated to the opening 80 on the closed side, and the combustion gas temperature rises.
[0126]
In this example, such a problem is solved by using the analog signal switch 78 to maintain the guide vane opening at the value at the time of detecting the abnormality when the intake air cooling system is abnormal.
[0127]
Specifically, a guide vane opening signal 77a [actual load + load shift amount corresponding to intake air temperature] output from the function generator 77 is input to one of the analog signal switch 78, and the analog signal switch The output signal 78 is returned to the other input of the analog signal switch 78, and the analog signal switch 78 is controlled by a runback command 26a output from the SR circuit 26.
[0128]
Then, the opening controller 74 controls the actuator 20 based on the guide vane opening signal 78 a from the analog signal switch 78.
[0129]
As a result, the analog signal switch 78 gives the guide vane opening signal 77a of the function generator 77 to the opening controller 74 as it is while the runback command 26a is "0", but the runback command 26a is "1". ", The signal at that time is continuously given to the opening degree controller 74.
[0130]
Therefore, in the case of partial load, even if the fuel flow rate is reduced due to an abnormality in the gas turbine intake air cooling system and the load is reduced, the guide vane opening is detected as shown in FIG. 10 regardless of the response delay of the intake air temperature sensor 19. The opening degree 79 at the time is maintained, and an increase in the combustion gas temperature is prevented. FIG. 11 shows the effect of preventing the turbine inlet temperature rise.
[0131]
As another example, instead of returning the output signal 78a of the analog signal switch 78, a guide vane is provided when the intake air cooling system is abnormal, such as by providing a full open signal 81 indicating the full open of the guide vane to the other input of the analog signal switch 78. The opening may be controlled to be larger than the opening 79 at the time of abnormality detection.
[0132]
In the above-described embodiments, the analog signal switching unit is used and function generation and various controls are all performed by analog signal processing. However, various signal switching units, signal generators, and function generators are used. In addition, all or some of the signal processors such as various controllers may be digital devices.
[0133]
In the above-described embodiment, the fuel flow rate is instantaneously reduced due to an abnormality in the intake air cooling system of the gas turbine. As an application, the fuel pressure control valve 6 is controlled by PI control for various purposes. The present invention can be applied when it is desired to decrease or increase the fuel flow rate instantaneously without being affected by the delay.
[0134]
For example, in FIG. 4, the SS circuit 27 is supplied with a change command for reducing or increasing the fuel according to the purpose instead of the runback command 26a, and the analog memory 41 is supplied with the fuel supply signal instead of the adjusted runback target signal 37a. A governor setting target signal that matches the decrease or increase is given, and in FIG. 7, a fuel change command that suits the purpose is given to the SS circuit 63 instead of the runback command 26a.
[0135]
At this time, the analog settling opening signal 65a generated by the function generator 65 represents the opening on the open side that is set after switching the governor set value when the fuel is reduced, and the closed side that is set after switching the governor set value when the fuel is increased. Represents the degree of opening.
[0136]
Therefore, when it is desired to reduce or increase the fuel flow rate for various purposes, the governor set value is instantaneously switched from the current value to a predetermined set value lower or higher, and at that time, the fuel pressure control valve 6 Since the opening is set prior to the opening that is settled after switching the governor set value, the governor set value is set to a set value corresponding to the desired fuel flow rate, whereby the fuel pressure control valve 6 is controlled by PI control. The fuel flow rate decreases or increases instantly without being affected by the delay.
[0137]
【The invention's effect】
  BookThe gas turbine protection device of the invention includes an abnormality detection means for detecting an abnormality in the intake air cooling system of the gas turbine, and instantaneously sets the fuel flow rate of the gas turbine when the abnormality of the intake air cooling system is detected.Preset fuel flow setBecause the fuel flow instantaneous reduction means is reduced to a value, even if an abnormality occurs in the gas turbine intake cooling system using a refrigerant such as water and the intake air temperature rises rapidly, the combustion gas temperature is prevented from rising and the gas A turbine failure can be reliably avoided, and the operation of the gas turbine can be continued. Therefore, in the case of a gas turbine power generation facility, failure of the gas turbine can be avoided while continuing power generation.
[0138]
  BookThe gas turbine protection device of the invention isThe set fuel flow ratevalueBut, A load calculated as a function of atmospheric temperature, and the turbine inlet temperature isPre-set settingsSince the value is based on a load that does not exceed the temperature, failure of the gas turbine can be reliably avoided even if the atmospheric temperature fluctuates.
[0139]
  BookThe gas turbine protection device of the invention isAboveMeans for instantaneously reducing fuel flowButThe governor set value for controlling the rotational speed of the gas turbine is lower than the current value.Pre-set governorIt includes a governor set value instantaneous switching means that switches to the set value instantaneously, so that an abnormality occurs in the gas turbine intake air cooling system using a refrigerant that has a cooling effect higher than that of water, and an effective rapid increase in combustion gas temperature is effectively achieved. Can be prevented.
[0140]
  BookThe gas turbine protection device of the invention isGovernorSet valueButSince the value is calculated as a function of the atmospheric temperature, it is possible to reliably avoid a gas turbine failure even if the atmospheric temperature fluctuates.
[0141]
  BookThe gas turbine protection device of the invention isAboveMeans for instantaneous fuel reductionButThe fuel pressure control valve opening advance setting means for setting the opening of the fuel pressure control valve in advance of the opening settling after the fuel amount is reduced when an abnormality is detected in the intake air cooling system. It is possible to prevent the combustion gas temperature from increasing due to the control delay caused by the PI control. As a result, it is not necessary to significantly reduce the fuel flow rate in order to prevent the combustion gas temperature from rising, and therefore it is possible to suppress a decrease in load when the fuel is reduced.
[0142]
  BookThe gas turbine protection device of the invention isAboveMeans for instantaneously reducing fuel flowButIn addition, when an abnormality is detected in the intake air cooling system, it includes guide vane opening control means that maintains the guide vane opening of the air compressor at the opening when the abnormality is detected or controls it to the open side, so that intake air cooling during partial load operation In the event of an abnormality in the system, even if there is a response delay in the intake air temperature sensor that measures the intake air temperature at the air compressor inlet, it is possible to prevent the combustion gas temperature from increasing due to a decrease in the load when the fuel flow rate decreases. it can. Thereby, it is not necessary to greatly reduce the fuel amount, and the load reduction when the fuel flow rate is reduced can be suppressed to a small extent.
[0143]
  BookThe gas turbine protection device of the invention isAboveThe abnormality detection means detects when the pump to be operated for sending the refrigerant for intake air cooling stops, or when the deviation between the command value of the refrigerant flow rate and the actual refrigerant flow rate isPreset deviationWhen the range is exceeded or the actual refrigerant flow isPreset refrigerant flow set in advanceWhen the value is lower than the value, it is detected that the intake air cooling system is abnormal, so that the abnormality of the intake air cooling system can be reliably detected.
[0144]
  BookThe gas turbine protection device of the invention detects that the intake air cooling system is abnormal when there are a plurality of pumps to be operated to send the intake air cooling refrigerant, and two pumps stop at the same time. Can be reliably detected.
[Brief description of the drawings]
FIG. 1 is a diagram showing an outline of a gas turbine power generation facility according to an embodiment of the present invention.
FIG. 2 is a diagram showing a configuration example of intake air cooling system abnormality detection means.
FIG. 3 is a diagram showing an example in which a plurality of pumps for sending refrigerant are used.
FIG. 4 is a diagram showing a configuration example of a fuel flow rate instantaneous reduction means.
FIG. 5 is a view showing a row selector for selecting a control signal.
FIG. 6 is a diagram showing an example of a circuit for generating a runback target value in governor setting.
FIG. 7 is a diagram showing a configuration example of fuel pressure control valve opening advance setting means.
FIG. 8 is a diagram showing the operation of the fuel pressure control valve opening advance setting means.
FIG. 9 is a diagram illustrating a configuration example of a guide vane opening degree control unit.
FIG. 10 is a diagram illustrating an example of a guide vane opening control line.
FIG. 11 is a diagram showing the effect of preventing the turbine inlet temperature rise by maintaining the guide vane opening.
[Explanation of symbols]
1 Intake chamber
2 Intake filter
3 Intake duct
4 Air compressor
5 Combustors
6 Fuel pressure control valve
7 Fuel flow control valve
8 Turbine
9 Generator
10 Refrigerant supply pipe
11 Pump
12 Refrigerant piping
13 nozzles
14 Gas turbine protection device
15 Pump stop sensor
16 Refrigerant flow sensor
17 Atmospheric temperature sensor
17a Atmospheric temperature signal
18 Differential pressure sensor
18a Differential pressure measurement signal
19 Intake air temperature sensor
19a Intake air temperature signal
20 Guide vane drive actuator
21 Intake air cooling system abnormality detection means
21a Runback request in case of abnormal intake air cooling system
22 Means for instantaneously reducing fuel flow
23 Fuel pressure control valve opening advance setting means
24 Guide vane opening control means
25 AND circuit
26 Set reset circuit (SR circuit)
26a Runback command
27 Single shot timer (SS circuit)
27a Pulse signal (SS circuit 27 output pulse)
28 Subtractor
29 Lower limit monitor
30 knot circuit
31 Subtractor
32 Lower limit monitor
33 AND circuit
34 timed timer
35 OR circuit
36 knot circuit
37 Adder
37a Adjustment runback target signal
38 Analog signal generator for adjustment
38a Analog signal for adjustment
39 Analog signal selector
40 Analog signal generator for dummy
40a Analog signal for dummy
41 Analog memory
42 Adder
43 Subtractor
44 Governor gain device (proportional controller)
45 Actual load signal
46 Runback permission load signal
47 Runback target signal
48 Load control tracking signal
49 Rated speed bias signal
50 Initial load bias signal
51 Rotational speed signal
52 Low selector
53 Subtractor
54 Function generator
54a Maximum allowable load signal according to atmospheric temperature
55 Subtractor
56 Low selector
57 Actual operation output signal
58 First predetermined value signal
59 Second predetermined value signal
60 Generator parallel signal
61 Subtractor
62 Proportional integral (PI) controller
62a External signal input terminal
62b Control terminal
63 Single shot timer (SS circuit)
63a Pulse signal (SS circuit 63 output pulse)
64 Analog signal selector
65 Function generator
65a Analog settling position signal
66 Fully closed analog opening signal generator
67 Analog opening signal generator for pressure release
68 Analog opening signal generator for ignition
69 Analog signal selector
70 Analog signal selector
71 Differential pressure setting signal
72 Large load reduction
73 Small load reduction
74 Opening controller
75 Function generator
75a Load shift signal
76 Adder
77 Function generator
77a Guide vane opening signal
78 Analog signal selector
78a Guide vane opening signal
79 Guide vane opening at the time of intake air cooling system abnormality
80 Closed guide vane opening
81 Guide vane fully open signal
SPSET governor set value
CSO Fuel flow control valve opening control signal
GVCSO governor control signal
LDCSO load control signal
BPCSO Blade path temperature control signal
EXCSO exhaust gas temperature control signal

Claims (4)

An abnormality detection means for detecting an abnormality in the intake air cooling system of the gas turbine;
A fuel flow instantaneous reduction means for instantaneously reducing the fuel flow rate of the gas turbine to a preset fuel flow rate value when an abnormality is detected in the intake air cooling system ;
The fuel flow rate instantaneous lowering means is
A governor set value instantaneous switching means for instantaneously switching a governor set value for controlling the rotational speed of the gas turbine from a current value to a preset governor set value lower than the present value;
A fuel pressure control valve opening advance setting means for setting the opening of the fuel pressure control valve in advance of the opening settling after the fuel amount is reduced when an abnormality is detected in the intake air cooling system;
Including a guide vane opening degree control means for maintaining the air vane opening degree of the air compressor at the opening degree at the time of abnormality detection or controlling it to the open side when the abnormality is detected in the intake air cooling system;
The abnormality detecting means is used when the pump to be operated for sending the refrigerant for intake air cooling stops, or when the deviation between the command value of the refrigerant flow rate and the actual refrigerant flow exceeds a preset deviation range, or actually A gas turbine protection device that detects that the intake air cooling system is abnormal when the refrigerant flow rate of the refrigerant is lower than a preset refrigerant flow rate value . The gas turbine protection device according to claim 1,
The gas turbine protection device according to claim 1, wherein the set fuel flow rate value is a load calculated as a function of the atmospheric temperature and based on a load in which the turbine inlet temperature does not exceed a preset set temperature. The gas turbine protection device according to claim 1,
The gas turbine protection device, wherein the governor set value is a value calculated as a function of atmospheric temperature. In the gas turbine protection device according to any one of claims 1 to 3 ,
The abnormality detecting means detects that the gas turbine intake cooling system is abnormal when there are a plurality of pumps to be operated to send the intake cooling refrigerant and when two of the pumps stop simultaneously. Gas turbine protection device.

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