JPS6038522B2 - Turbine control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a turbine control device, and particularly to a turbine control device that takes its reliability into consideration.

Generally, a turbine control device is composed of a speed control section 2 and a valve opening control section 3, as shown in a first block 1, and controls the flow rate of steam flowing into the turbine 4 based on an input speed command signal a. By adjusting, the speed of the turbine 4 is controlled according to the command value. That is,
The input speed command signal a is compared with the speed signal b fed back from the speed detector 5 of the turbine 4 by the comparator 21 of the speed control section 2, and the deviation signal is subjected to compensatory calculation by the compensator 22, and then the valve is converted into a degree command signal c.

This valve opening command signal c is combined with an actual speed signal d fed back from a valve opening detector 7 provided in a valve 6 that controls the flow rate of steam flowing into the turbine 4 by a comparator 31 of a valve opening controller. be compared. The deviation signal is converted into a relationship adjustment signal d via a compensator 32. This opening adjustment signal d adjusts the valve 6 via the valve reversal unit 8, and the amount of steam flowing into the turbine 4 is adjusted. As a result, the turbine 4 is accelerated or decelerated depending on the amount of incoming steam and the actual load, and finally steady operation is performed with both of them being balanced. By the way, since a generator (not shown) is connected to the turbine 4 and outputs the generated power to the power grid, the control of the turbine 4 may not be normal due to a failure of the turbine control device 1 itself or a failure of the speed detector 5. If this is not done properly, it will have a negative impact on the power system, such as frequency fluctuations, and in the worst case, it will also disrupt system operation.

For this reason, the follower is provided with a plurality of valves 6, a valve opening degree detector 7, and a valve reversal part 8 in the steam path that supplies the steam flow rate to the turbine 4, and two speed detectors 5 are provided, and the turbine The control device was constructed as shown in Figure 2 in order to improve the reliability of the turbine control device.

That is, the actual speed signals q and Q fed back individually from the two speed detectors 5 are compared with the speed command signal a in the corresponding two systems of speed control sections 2, and a deviation compensation calculation is performed. are converted into valve opening command signals c, , c2.

These valve opening command signals c, , c2 are sent to the low value selection circuit 9
Accordingly, the signal c having an algebraically low value is selected and outputted to the plurality of valve function control units 3. This valve function command signal c is an actual opening degree signal d. which is fed back individually by each valve opening degree control section 3. , Q, d3..., deviation compensation calculation is performed, and the respective valve opening adjustment signals, , e2, e
2... are converted and output to the corresponding valve drive units 8, and the turbine 4 is controlled. According to the above conventional configuration, since there are two systems of the speed detector 5 and the speed control section 2, an abnormality occurs in one of these two systems; As a result, even if one of the valve opening command signals c, c2 becomes abnormally high, a normal signal is selected by the low value selection circuit 9 and is sent to each valve opening control unit as the valve opening command signal c. 3 is output.

Therefore, in the event of a failure in the speed detector 5 or the speed control unit 2 in which either the valve opening command signal or c2 becomes abnormally high, normal operation continues, and the turbine control device An improvement in reliability can be seen. However, in the conventional turbine control device described above, when a failure occurs in which one of the valve opening commands c, c2 falls to an abnormally low value, the low value selection circuit 9 selects the signal of the failure system. is,
As a result, the valve 6 is controlled in the closing direction, and the turbine is stopped, even though the other system is outputting a normal valve function command signal.

'2) When the function of one of the two systems is stopped in order to inspect the speed detector 5 or the speed control unit 2, the valve function command signal c. , c2 becomes abnormally low, leading to a shutdown of the operation. {3') Since the low value selection circuit 9 does not have redundancy, if this circuit were to fail, there would be problems such as control of all valves 6 becoming impossible. The present invention provides a highly reliable turbine that allows normal operation of the turbine even if either a high or low abnormal signal occurs due to a single failure in the turbine speed detector or control device internal system, except for the above-mentioned problems. The purpose is to provide a control device.

In order to achieve this object, the present invention provides three speed detectors and three speed control units for the turbine, and sends an intermediate value of each actual speed signal output from each speed detector to each speed control unit. The present invention is characterized in that an intermediate value of the signals input and further output from each speed control section is input to the valve speed control section as a valve speed command signal.

The present invention will be explained below with reference to FIG.

FIG. 3 is a schematic diagram of a turbine control device according to an embodiment of the present invention, in which the same reference numerals as in FIGS. 1 and 2 indicate the same or corresponding parts, and the conventional configuration The difference is that three speed detectors 5 and three speed control sections 2 are provided, and intermediate value selection circuits 10 and 11 are provided in front of each speed control section 2 and valve control degree control section 3, respectively. The actual speed signals q, b2, b3 output from the three speed detectors 5 are input to the intermediate value selection circuit 101, while the valve opening signals output from the three speed controllers 2 are inputted to the intermediate value selection circuit 101. ，
, c2, and c3 are input to each intermediate value selection circuit 11, thereby increasing the reliability of the turbine control device.
The intermediate value selection circuits 10 and 11 are configured to select and output a signal having an algebraic intermediate value from among the three input signals.

The turbine control device of this embodiment is configured as described above,
Actual speed signals output from three speed detectors 5, Q,
b3 is input to each intermediate value selection circuit 101, respectively.

Then, each intermediate value selection circuit 10 outputs a signal indicating the algebraic intermediate value, that is, bm=mean(q, Q,
b3) ...0] is output.

As described above, the actual speed signal bm is compared with the speed command signal a in the speed control section 2, and the deviation compensation calculation is performed, and the three speed control sections 2 output the valve opening command signal c, , c2, c3 are output. Similarly, these valve function command signals c, c2, c3 are also input to each intermediate value selection circuit 11 provided before the plurality of valve opening degree control sections 3, and each intermediate value direct selection circuit From 11, cm=mea
A valve function degree signal cm of n(c,,c2,c3)...'21 is output.

Furthermore, this valve opening degree signal cm and the actual valve relationship signal d,, are also
3..., each valve opening degree control section 3 outputs each valve opening degree adjustment signal el'e2'e3.... These valve function adjustment signals e,, e2, e3... adjust the opening degree of the valve 6 provided in parallel to the turbine steam inflow path. Even if a single failure occurs, the rotational speed of the turbine is always controlled according to the command value.

That is, the actual speed signal q now output from each speed detector 5
, Q, b3 have the following values.

b,=Q+8, …[3
}Q=Q ...{4}Q
=Q-B2...{51 (however, 8, , 82 are both positive values close to 0) Then, according to the above formula '1-, the intermediate value selection circuit 10 outputs the actual speed signal bm=Q=Q is output.

At this time, the actual speed signals become abnormal, and b2>Q+6.
If it changes to , then bm=b,=Q+8, and instead of the actual speed signal Q, it is selected and output. On the other hand, if the actual speed signal b{knee changes to wide Q-82, bm=wide=Q
+82, and the beautiful speed signal is selected and output.
Therefore, regardless of whether the actual speed signal is abnormally high or abnormally low, the beautiful speed signal bm output from the intermediate value selection circuit 10 remains at most 8 (8=B, or 82), and the speed It can be seen that the spread of detector failure is prevented.

Of course, the same applies not only to abnormalities in the beautiful speed signal Q but also to abnormalities in the actual speed signal b or b3. Similarly, each speed control section 2 outputs a valve function command signal c. , c2, c3 are selected and output by the intermediate value selection circuit 11, resulting in valve opening command signals C,, C
Even if one of the signals C2 and C3 becomes abnormally high or abnormally low, a normal valve opening command signal cm is input to each valve opening control section 3.

In this way, an abnormality in one of the actual speed signals q, Q, b3 due to a single failure in the speed detector 5 is compensated for by the other actual speed signal, and the single fault in the speed controller 2 An abnormality in one of the valve opening command signals c, c2, c3 caused by a single failure is compensated for by the other valve opening command signal. In addition, a single failure in the speed control section will not affect the downstream valve control section, allowing operators to continue operating.In addition, in this embodiment, there are three Even if the speed detector 5 or one of the speed controllers 2 is disconnected from the control loop for inspection, there will be no problem in the operation of the turbine for the reasons mentioned above.Furthermore, in this embodiment, the intermediate value selection circuit 1
0 attached to each speed control section 2, even if one of them breaks down, the operation will not be affected as described above.

In addition, the three actual speed signals b, , Q, b in the above embodiment
By monitoring the valve opening command signals c, , c2, and c3, it is possible to diagnose a failure in the speed detector 5 and the speed control unit 2, thereby increasing the reliability of the turbine control device. can.

Furthermore, even if the valve 6 cannot be adjusted due to a failure in the intermediate value selection circuit 11 or the valve opening control unit 3, it is possible to continue operating the turbine in an emergency by compensating with the load command from the upper loop. . Furthermore, in the above embodiment, the intermediate value selection circuits 10 and 11 are provided attached to each speed B control section 3 to increase redundancy and improve reliability. , 1 can be reduced if the reliability of the circuit itself is very high compared to other circuits.

As described above, according to the present invention, three speed detectors and three speed control units are provided, and the intermediate value signal of the three signals output from the previous stage is supplied to the next stage. An extremely reliable turbine control system that allows normal operation even when high or low abnormal signals are caused by a single failure in the speed detector or speed control unit, allows online maintenance and inspection, and minimizes the effects of failures. It will be done.

[Brief explanation of drawings]

Figure 1 is a block diagram of a general turbine control device.
FIG. 2 is a block diagram of a main part of a conventional turbine control device, and FIG. 3 is a block diagram of a turbine control device showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Turbine control device, 2... Speed control part, 3...
...Valve function control section, 4...Turbine, 5...Speed detector, 6...Valve, 7...Valve opening degree detector, 8...Valve drive unit, 9... Low value selection circuit, 10, 11... Intermediate value selection circuit, 21, 31... Comparator, 22, 23...
・Compensator. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1 A speed detector that detects the rotational speed of the turbine and outputs an actual speed signal; and a speed detector that inputs the speed command signal and the actual speed signal to output a valve opening command signal for adjusting the turbine steam flow rate; and a valve opening control section that receives the valve opening command signal and the actual valve opening signal as input, outputs a valve opening adjustment signal, and controls the valve opening. In the turbine control device, three speed detectors and three speed control units are provided, and
An intermediate value selection circuit is provided before the speed control section and the valve opening control section, and a signal of an intermediate value of the three actual speed signals output from the three speed detectors is supplied to the speed control section. At the same time, the turbine control device is characterized in that a signal having an intermediate value of the three valve opening command signals outputted from the three speed control sections is supplied to the valve opening control section.