JPH0424798Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an output control device for a turbine generator, and in particular, the rotation of the turbine generator is controlled when the load of the turbine generator is interrupted or an electrical accident occurs in the power plant. The present invention relates to an output control device for a turbine generator that suppresses rise.

[Technical background of the invention and its problems]

In recent years, the capacity of single turbine generators in steam power plants has been increasing. However, the moment of inertia of the turbine generator does not increase as much as the capacity increases, making it difficult to suppress the increase in rotation of the turbine generator to within a specified value when the load is off. For this reason, recent large-capacity thermal power machines are generally equipped with a load sensing device as an auxiliary means to the mechanical-hydraulic control device. The load sensing device operates before the mechanical-hydraulic control device detects the increase in rotation speed of the turbine generator due to load interruption of the turbine generator, and operates the steam control valve and intercept valve of the turbine. This is to control the output of the turbine generator by rapidly closing the turbine generator and suppressing the increase in rotational speed of the turbine generator to within a specified value.

FIG. 1 shows a block diagram of a signal processing system in a conventional load sensing device.

FIG. 1 is a block diagram of a signal processing system that forms a valve closing signal for rapidly closing an intercept valve 1 and a steam control valve 2 that control the amount of steam flowing into the turbine. Generator output Pe, generator current I, and reheat steam pressure Ph of the turbine generator (not shown) detected by each detector (not shown)
Each detected value is input to each judger 3, 4, 5,
It is compared with each setting value K. When the detector 3 determines that the detected value Pe of the generator output is smaller than the set value _K1 , a determination signal is output to the first AND circuit 6. Further, when the detected value I of the generator current is determined by the determiner ₄ to be smaller than the set value K3, a determination signal is outputted to the second AND circuit 7. Furthermore, the detected value Ph of the reheating steam pressure is determined by the judgment unit 5.
When it is determined that the value is larger than the set value, the determination signal is passed through the hold circuit 8 to the first and second
The signals are input to both 2AND circuits 6 and 7, respectively.
The first AND circuit 6 is the setter 3 and the hold circuit 8
When the judgment signals outputted from the two are input together, a valve closing signal 9 is outputted to the intercept valve 1, and the intercept valve 1 is rapidly closed. On the other hand, when the judgment signals output from the setting device 4 and the hold circuit 8 are both input, the second AND circuit 7 outputs the valve closing signal 9 to the steam regulating valve 2, and quickly closes the steam regulating valve 2. It's starting to close. The hold circuit 8 holds the output of the determination signal from the determiner 5, which receives the detected reheat steam pressure value Ph, for a required period of time, for example, about 1 to 2 seconds.

Then, the load on the turbine generator was interrupted, and
When the turbine generator is separated from the grid, the detected values of the generator output Pe and generator current I of the turbine generator become zero. Therefore, at this time, if the detected value of the reheat steam pressure Ph is larger than the set value _K2 of the determiner 5, the determination signals from the respective determiners 3, 4, and 5 are sent to the first and second AND circuits 6, 7, this first,
A valve closing signal 9 is output from the second AND circuits 6 and 7, respectively. As a result, the intercept valve 1 and the steam control valve 2 are quickly fully closed, and the turbine output is rapidly reduced. As a result, an increase in the rotational speed of the turbine generator is suppressed, and the output of the turbine generator is controlled.

However, such conventional load sensing devices have the following problems. One such problem is that when a failure occurs in the power transmission system, the generator output Pe of the turbine generator decreases, and the generator current I increases, the intercept valve 1 is completely closed. In other words, in this case, the
The determination signals from the determiner 3 and the hold circuit 8 are input to the 1AND circuit 6, and the first AND circuit 6
A valve closing signal is output to intercept valve 1,
Intercept valve 1 is fully closed. However, in the event that some kind of failure occurs in the power transmission system, protection devices installed on the power transmission line will eliminate most of the obstacles caused by the failure and restore stable operation.
The increase in the rotational speed of the turbine generator is small compared to when the load is cut off, and there is no need to intentionally close the intercept valve 1. Rather, once the intercept valve 1 is fully closed, the fully closed state continues for at least 1 to 2 seconds, and the rotational speed of the turbine generator decreases, and then the intercept valve 1 is fully opened and the original state is restored. It will take about 10 seconds. Therefore, while the turbine generator remains connected to the grid, the number of rotations is significantly reduced, which poses a problem in that the influence on the grid is large.

In addition, if an electrical accident occurs in a power plant that causes the rotation speed of the turbine generator to increase,
There was a problem in that the output of the valve closing signal 9 to the steam control valve 2 was delayed, and during that time the increase in rotational speed of the turbine generator could not be suppressed, causing the load to increase more than when it was off. That is, when an electrical accident occurs within a power plant, it is detected by an in-house protection relay (not shown), and a lockout relay is activated to trip the generator or disconnector. It takes approximately 0.1 to 1 second from the occurrence of this accident to the tripping of the generator or disconnector, and during this time the fault current associated with the above-mentioned in-house electrical accident flows through the turbine generator. For this reason, the detected value I of the generator current becomes larger than the set value of the determiner 4, and the determiner 4 does not output a determination signal. As a result, the valve closing signal is not output from the second AND circuit 7, and the steam control valve 2 does not close, so the increase in the number of revolutions of the generator after the generator or disconnector trips is rather a result of the load or disconnection. It gets bigger.

[Purpose of the invention] This invention was created in view of the above-mentioned circumstances.
It does not operate when there is a system failure in the power transmission system, etc., and when the load on the turbine generator is cut off or an electrical accident within the power plant (limited to electrical accidents that increase the rotation speed of the turbine generator), the intercept valve and the above adjustment are used. An object of the present invention is to provide an output control device for a turbine generator that can rapidly close a valve and suppress an increase in the rotational speed of the turbine generator to within a specified value.

[Summary of the idea]

In order to achieve the above object, a turbine generator output control device according to the present invention is configured as follows.

Each detection detects, respectively, the in-plant fault electricity amount of a power plant equipped with a turbine generator driven by a turbine, the pressure of reheated steam supplied to the turbine, and the generator current and generator output of the turbine generator. and each determination device that compares and determines each detected value detected by each of these detectors with each set value, and determines whether the detected value of the generator current is less than or equal to the set value,
and a first AND circuit that outputs a valve closing signal when the detected value of the reheat steam pressure is determined by each of the determining devices to be equal to or higher than the set value, and a first AND circuit that outputs a valve closing signal when the detected value of the generator output is equal to or lower than the set value, and and a second AND circuit that outputs a valve closing signal when the detected value of the reheat steam pressure and the detected value of the accident electricity amount in the power plant are determined by each of the above-mentioned determination devices to be greater than each set value, and the first AND The valve closing signal output from the circuit or the second AND circuit closes the intercept valve and the steam control valve that control the amount of steam flowing into the turbine.

[Example of idea]

An embodiment of the turbine generator output control device according to the present invention will be described below with reference to FIG. 2.

FIG. 2 is a block diagram of a signal processing system according to an embodiment of the present invention. In this embodiment, the first AND circuit 10 operates when the load of the turbine generator is interrupted.
and a second AND circuit 11 that operates when an electrical accident occurs in the power plant that increases the rotational speed of the turbine generator.

The first AND circuit 10 operates when the output signals from the first determiner 12 and the hold circuit 13 are input at the same time, as shown in FIG. The first determiner 12 compares a detected value I output from a detector (not shown) for detecting a generator current I of a turbine generator (not shown) with a set value KL ₁ , and this detected value I is the set value. A judgment signal is output when it is smaller than KL ₁ . The hold circuit 13 consists of a timer that holds the output of a judgment signal from a second judgment device 14 (described later) to the first AND circuit 10 for a required period of time, for example, about 1 to 2 seconds. This is because if this hold circuit 13 is omitted, the intercept valve 1 etc. will be closed in response to the output of the determination signal from the second determiner 14, and when the intercept valve 1 is closed, the reheat steam pressure will be
It becomes smaller than the set value KL ₂ of the determiner 14, and the operation of the second determiner 14 immediately returns, and the intercept valve 1 is also closed accordingly. As a result, it becomes impossible to effectively suppress the increase in rotational speed of the turbine generator when the load is on or off. The second determiner 14 sets a detected value Ph output from a detector (not shown) that detects the pressure of reheated steam supplied to a turbine (not shown) to a set value.
It compares it with KL ₂ and outputs a determination signal to the hold circuit 13 when this detected value Ph is larger than the set value KL ₂ . When the judgment signals output from the first and second judgment devices 12 and 14 are simultaneously input to the first AND circuit 10, the first AND circuit 10 outputs the valve closing signal 15 to the OR circuit 16. The determination signal from the second determiner 14 is also input to the second AND circuit 11 via the hold circuit 13. In addition, the detected value Pe output from a detector (not shown) that detects the generator output Pe of the turbine generator is compared with its set value KL ₃ in the third judger 17, and this set value
When it is smaller than KL ₃ , the third determiner 17 outputs a determination signal. Electrical quantities that occur in the event of an electrical accident in a power plant are input to a protection relay 18, and when these electrical quantities exceed a set value of the relay 18, a determination signal is output. Judgment signals output from the hold circuit 13, third judge 17, and protection relay 18 are input to the second AND circuit 11, and a valve closing signal output from the second AND circuit 11 is input to the OR circuit 16. . This OR circuit 16 intercepts the valve closing signal 15 when both or one of the valve closing signals 15 output from the first and second AND circuits 10 and 11 is input. , and both valves 1 and 2 are closed.

Next, the operation of this embodiment will be described.

If the turbine generator is overloaded or disconnected,
The first AND circuit 10 in the part surrounded by the broken line in Fig. 2
works. That is, this turbine generator is separated from the grid, and both the generator output Pe and the generator current I become zero. Therefore, at this time, when the reheat steam pressure Ph is larger than the set value KL ₂ of the second judge 14, the judgment signals are simultaneously inputted to the first AND circuit 10 from the first judge 12 and the hold circuit 13. satisfies the AND condition. As a result, the valve closing signal 15 is output from the first AND circuit 10.
The valve closing signal 15 that is input to the OR circuit 16 and further satisfies the OR condition is sent to the intercept valve 1.
and steam control valve 2, and both these valves 1,
2 is rapidly closed. For this reason, an increase in the rotational speed of the turbine generator coupled to the turbine is suppressed. Note that in the case of this load interruption, the protection relay 18 does not operate, so the second AND circuit 11 does not output a valve closing signal.

Next, for example, when a system fault occurs in a power transmission system or the like, the generator output Pe of the turbine generator generally decreases and the generator current I increases. Therefore, the condition I<KL ₁ of the first judge 12 cannot be satisfied, and even if the condition Ph>KL ₂ of the second judge 14 is satisfied, the AND condition of the first AND circuit 10 cannot be satisfied. , the valve closing signal 15 is not output. Therefore, when a system accident occurs, the closing operations of the intercept valve 1 and the steam control valve 2 are prevented.

In addition, if an electrical accident occurs in a power plant that increases the rotation speed of the turbine generator,
Similar to the above-mentioned system fault, generator output Pe decreases, generator current I increases, and protection relay 1
8 operates by detecting various electrical quantities associated with an electrical accident within the station. Therefore, when the reheating steam pressure Ph is greater than the set value KL ₂ during this electrical accident, the second determiner 14's Ph>KL ₂ and the third determiner 17's Pe<
Since the condition of KL ₃ is satisfied and the protection relay 18 is operating, the
The AND condition of the 2AND circuit 11 is satisfied, and this
The valve closing signal 15 is sent from the 2AND circuit 11 to the OR circuit 16
Output to. At this time, the AND condition of the first AND circuit 10 is not satisfied because the first determiner 12 is not operating, and the valve closing signal 15 is not output to the OR circuit 16. However, due to the input of the valve closing signal 15 from the second AND circuit 11, the OR condition is satisfied, and this valve closing signal 15 is transferred to the intercept valve 1 and the steam control valve 2 by this OR circuit 16. Both the steam control valve 2 and the steam control valve 2 are rapidly closed. As a result, the rotational speed of the turbine decreases, and accordingly, an increase in the rotational speed of the turbine generator is suppressed, and the output of the turbine generator is controlled.

[Effect of idea]

As described above, the present invention rapidly closes both the intercept valve and the steam control valve when an electrical accident occurs in a power plant that increases the rotational speed of the turbine generator, or when the load on the turbine generator is interrupted. This prevents the intercept valve and the steam control valve from closing in the event of a power transmission system fault, and prevents the turbine generator's rotational speed from significantly decreasing due to the closure of both valves. Adverse effects on the system can be prevented in advance and reliably. In addition, in the event of an electrical accident within the power plant, both the intercept valve and the steam control valve are quickly closed without tripping the turbine generator's shield, allowing the turbine generator's rotational speed to rise quickly and reliably. This has the effect of suppressing the output within a specified value and controlling the output.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a signal processing system using a conventional output control device for a turbine generator, and FIG. 2 is a block diagram of a signal processing system using an embodiment of the output control device for a turbine generator according to the present invention. be. 1...Intercept valve, 2...Steam control valve,
6, 10... 1st AND circuit, 7, 11... th
2AND circuit, 12...First judger, 13...Hold circuit, 14...Second judger, 15...Valve closing signal, 16...OR circuit, 17...Third judger, 1
8...Protection relay.

Claims (1)

[Claims for Utility Model Registration] 1. The amount of electricity at the time of an on-site accident in a power plant equipped with a turbine generator driven by a turbine, the pressure of reheated steam supplied to the turbine, and the generator current of the turbine generator. and a generator output, a detector that compares each detected value detected by these detectors with each set value, and determines whether the detected value of the generator current is equal to or less than the set value and the above-mentioned A first AND circuit that outputs a valve closing signal when the detected value of the reheat steam pressure is determined by each of the above-mentioned judgment devices to be equal to or higher than the set value, and a first AND circuit that outputs a valve closing signal when the detected value of the generator output is equal to or lower than the set value, and the reheated a second AND circuit that outputs a valve closing signal when the detected value of the steam pressure and the detected value of the amount of electricity at the time of an accident within the power plant are determined by each of the above-mentioned judgment devices to be greater than each set value; 1. An output control device for a turbine generator, characterized in that an intercept valve and a steam control valve that control the amount of steam flowing into the turbine are closed by a valve closing signal output from a circuit or a second AND circuit. 2. The determiner which receives the detected value of the reheat steam pressure as input is connected to the first AND circuit and the second AND circuit through a hold circuit that holds the output of the signal from the determiner for a predetermined period of time. An output control device for a turbine generator according to Claim 1 of the Utility Model Registration Claim. 3 The first AND circuit and the second AND circuit are
The valve closing signal output from each AND circuit is
The output control device for a turbine generator according to claim 1, which is configured to be inputted to an intercept valve and a steam control valve via an OR circuit.