JPH0756203B2 - Rotational speed setting circuit of turbine speed governor - Google Patents

Description

The present invention relates to a rotation speed setting circuit in a speed governor of a steam turbine.

[Conventional technology]

Conventionally, a control system configured as shown in FIG. 5 is known as a control system for adjusting the rotation speed in this type of turbine speed governor. That is, in FIG.
Reference numeral 10 is a rotation speed setting device, 12 is a rotation speed secondary setting device, 14 is a comparing circuit, 16 is a rotation speed adjusting device, 18 is an adding circuit, 20 is a comparing circuit, and 22 is a valve opening adjusting device. Therefore, the rotation speed setter 10 receives an “up” or “down” signal of the rotation speed by an automatic command or a manual command via the OR circuits 24 and 26, respectively, and the input setting value is changed. A rate of change suitable for the characteristics or state of the turbine to be speed-controlled is given by the rotational speed secondary setting device 12, and this becomes the rotational speed setting signal. Next, the deviation between the rotation speed setting signal and the rotation speed detection signal is obtained by the comparison circuit 14, and this deviation signal is supplied to the rotation speed adjuster 16. The output signal of the rotation speed adjuster 16 is added to the load command signal from the output adjusting system (not shown) in the adding circuit 18 to obtain a valve opening setting signal. Therefore, the deviation between the valve opening setting signal and the valve opening detection signal is obtained by the comparison circuit 20, and this deviation signal is supplied to the valve opening controller 22. Therefore, the valve opening command signal output from the valve opening adjuster 22 controls the turbine control valve via the electro-oil converter (not shown), and the constant rotation speed operation (load Constant output operation).

According to the conventional turbine speed governor having such a control system, the speed increasing characteristic at the time of starting the turbine is as shown in FIG. That is, from the turning speed before starting, going up through the heat soak speed to the rated rotation speed while constantly controlling the speed using the speed governor, and after the turbine generator reaches the substantially rated rotation speed, It will be inserted into the system by the synchronous injection device, and thereafter load operation will be performed.

[Problems to be solved by the invention]

However, FIG. 7 shows an example of an electric power system including the turbine generator described above. That is, in FIG. 7, reference numeral 30 indicates a main turbine, 32 indicates a main generator, and the main generator 32 is connected to a bus 38 via a main transformer 34 and a main circuit breaker 36. A plurality of auxiliary machines 44 are connected in parallel to the output line of the main generator 32 via an in-house transformer 40, an in-house transformer secondary circuit breaker 42, and an auxiliary machine circuit breaker 46, respectively.

In a power system having such a configuration, in order to insert a turbine generator into the system, the main generator 32 is excited by an exciter (not shown) and then the rotational speed setting device 10 (see FIG. 5) of the speed governing device. (See), the main generator 32's terminal voltage is controlled by an automatic voltage regulator [AVR] (not shown) so that it is always maintained at a constant value. If the value of (voltage / frequency of the main generator 32) gradually increases and exceeds a predetermined limit value, the main transformer 34 or the on-site transformer
40 etc. are over-excited and there is a risk of burning. Also,
During a load operation of the turbine generator, due to an accident on the system side,
In the case where the main circuit breaker 36 is turned off and the unit is operating independently, if the speed setting value of the rotation speed setting device 10 of the speed governor is lowered, the main transformer 34 described above is used. ,
In addition to the problem of over-excitation of the transformer 40, etc.,
There is also a drawback that the danger of overexcitation and overcurrent of 46 is great.

Therefore, an object of the present invention is to provide a turbine speed control device that controls a rotation speed of a turbine generator by generating a valve opening command based on a rotation speed set value, when the speed increasing process of the turbine generator is once terminated. (EN) Provided is a rotation speed setting circuit of a turbine speed governor capable of effectively preventing a system failure due to a down command to a rotation speed setting device.

[Means for solving problems]

The rotation speed setting circuit of the turbine speed governor according to the present invention,
A rotation speed setting signal is obtained by inputting a rotation speed increase or decrease command to the rotation speed setter, and the valve opening is calculated by sequentially comparing and calculating the rotation speed detection signal, the load command signal and the valve opening detection signal. In a turbine speed governor configured to obtain a command signal and thereby control the turbine control valve to operate the turbine at a constant rotation speed that matches the set value, rotation based on an automatic command or a manual command to the rotation speed setter. To the output line of the OR circuit that inputs the speed reduction command,
A control circuit is provided for locking the rotation speed set value based on the lowering command so as not to be equal to or lower than the lower limit speed set value based on the condition of completion of the turbine speed increase and the lower limit speed set value.

In the above rotation speed setting circuit, the excitation ON operation signal of the turbine generator or the rated rotation speed set value and the turbine stop signal can be preferably used as the conditions for completing the speedup of the turbine.

[Action]

According to the rotation speed setting circuit of the turbine speed governor according to the present invention, a rotation speed increase command or a rotation speed decrease command is input to the rotation speed setting device to obtain a required rotation speed set value, and the valve opening degree is obtained from this set value. In a turbine speed governor that forms a command signal and performs a constant rotation speed operation, by determining the conditions and the lower limit speed setting value at this time when the speedup of the turbine is completed, the lowering command of the rotation speed is the lower limit. In order to maintain the safe system operation, limit the setting operation of the rotation speed setting device so that it does not fall below the speed setting value and prevent overexcitation of the transformer etc. in the power system where the turbine generator is also included. You can

〔Example〕

Next, an embodiment of a rotation speed setting circuit of a turbine speed governor according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a main part system diagram of a control system of a turbine speed governor showing a typical embodiment of a rotation speed setting circuit according to the present invention. In the system diagram shown in FIG. 1, the basic control system is the same as the conventional control system shown in FIG. 5, and therefore, the same components are designated by the same reference numerals and detailed description thereof will be omitted. The description is omitted. That is, the gist of the present invention is the input circuit of the "down" command to the rotation speed setting circuit 10 surrounded by the one-dot chain line in FIG.

In the embodiment shown in FIG. 1, the excitation ON operation signal of the turbine generator and the rated rotation speed are set to 100 at the output line of the OR circuit 26 which outputs a "down" command by an automatic command or a manual command.
When the lower limit speed setting value (for example, -6%) in the rotation speed setting device 10 is set as a condition, these excitation ON operation signals and the lower limit speed setting value are ANDed by the AND circuit 50. The "down" command is configured to be wiped out (locked) by the wipeout circuit 52. That is, according to the circuit of the present embodiment, even if an erroneous operation is performed or an erroneous operation signal is input in the power system in which the main generator that has once completed the speed-up and entered the process of voltage generation has been inserted. The speed setting value by the rotation speed setting device 10 is interlocked so that it does not fall below -6% of the rated rotation speed.

In this way, with respect to the set value input to the rotation speed setting device 10, the rotation speed secondary setting device 12 gives a change rate suitable for the characteristics and state of the turbine to be speed-controlled, and this is the rotation speed setting signal. Is similar to the conventional circuit. Therefore, the deviation between the rotation speed setting signal and the rotation speed detection signal is obtained by the comparison circuit 14, and this deviation signal is used as the rotation speed adjuster 16
Supply to. The output signal of the rotation speed adjuster 16 is added to the load command signal from the output adjusting system (not shown) in the adding circuit 18 to obtain a valve opening setting signal. Therefore, the deviation between the valve opening setting signal and the valve opening detection signal is obtained by the comparison circuit 20, and this deviation signal is supplied to the valve opening controller 22. Therefore, the valve opening command signal output from the valve opening adjuster 22 controls the turbine control valve via the electro-oil converter (not shown), and the constant rotation speed operation (load Constant output operation).

FIGS. 2 to 4 show different embodiments of the rotation speed setting circuit of the present invention.
The structure of the main part of the part surrounded by the dashed line is shown. FIG. 2 shows an OR circuit 26 that outputs a "down" command by an automatic command or a manual command, and an AND circuit 50 that outputs an AND condition of an excitation ON operation signal and a lower limit speed setting value, as in the above embodiment. The provided example is shown. Therefore, in the present embodiment, after the output of the AND circuit 50 is inverted via the NOT circuit 54, it is ANDed with the output signal of the OR circuit 26 via the AND circuit 56.
It is configured to obtain the condition. With this structure, the same interlock effect as that of the above-described embodiment can be obtained.

The embodiment shown in FIG. 3 outputs the excitation ON operation signal and the lower limit speed setting value to the OR circuit 26 which outputs a “down” command by an automatic command or a manual command via NOT circuits 58 and 60, respectively. Then, the outputs of the NOT circuits 58 and 60 are configured to select one condition via the OR circuit 62.
In the present embodiment, the output of the OR circuit 26 and the OR
By obtaining the AND condition with the output of the circuit 62 via the AND circuit 56, the same interlock effect as in the above-described embodiment can be obtained.

Compared with the embodiment shown in FIG. 1, in the embodiment shown in FIG. 4, the turbine generator reaches near the rated rotation speed (for example, 2950 rpm or more) instead of the condition of the excitation ON operation signal. , The conditions for outputting the turbine stop signal indicating that the speed-up has been completed are respectively adopted. in this case,
The rated rotation speed setting value and the turbine stop signal are alternately output via the flip-flop circuit 64, and either of these outputs and the lower limit speed setting value (for example, the rated rotation speed is 100%
, And -6%) and AND condition by AND circuit 50
Wipe out the "down" command output from the OR circuit 26
At 52, configure to wipe out (lock). Therefore, also in this embodiment, it is possible to obtain the same interlocking effect as each of the above embodiments.

In the above-described embodiment, the condition of the excitation ON operation automatically disappears at the time when the turbine stop signal is generated (excitation OFF operation). Therefore, in order to increase the speed of the turbine generator again, It does not hinder the automatic runback of the speed setter 10 to the lower limit speed set value.

In addition, the conditions for the excitation ON operation are the ON operation of the field breaker,
Indicates that the amount of exciting current and / or exciting voltage has reached a predetermined value, and that the amount of voltage and / or current of the main generator has reached a predetermined value. It goes without saying that the main generator is in the excited state and the preconditions for the excitation are included.

〔The invention's effect〕

As is apparent from the above-mentioned embodiments, according to the present invention,
The turbine generator starts up to the rated rotation speed set in the rotation speed setting device by the turbine speed governor, and once the turbine generator completes the speed increase to the rated rotation speed and the generator voltage is generated, incorrect operation or Even if a lowering command is issued to the rotation speed setting device by a malfunction signal, the rotation speed setting value of the rotation speed setting device is set by the logical condition based on the excitation ON operation and the signal equivalent to this, and the setting of the lower limit speed setting value. Can surely be interlocked so as not to become less than the lower limit speed set value. As a result, it is possible to easily prevent the danger caused by over-excitation of the main transformer, the in-house transformer, etc. provided in the electric power system in which the turbine generator is inserted.

In the above-described embodiment, the problem of over-excitation of the main transformer, the in-house transformer, etc. was mentioned as a risk that occurs when the set value of the rotation speed setting device is abnormally lowered after the excitation ON operation. No. 1 in the "down" command input circuit of the speed setter
By providing the interlocks as shown in FIGS. 4 to 4, it is of course possible to simultaneously prevent the turbine, the generator, the exciter, etc. from operating at a critical (resonance point) speed.

Although the preferred embodiment of the present invention has been described above, various design changes can be made without departing from the spirit of the present invention.

[Brief description of drawings]

FIG. 1 is a main part system diagram of a speed control system showing an embodiment of a rotation speed setting circuit of a turbine speed governor according to the present invention, and FIGS. 2 to 4 are rotation speed setting circuits according to the present invention, respectively. FIG. 5 is a main part system diagram showing a different embodiment, FIG. 5 is a main part system diagram of a conventional speed control system, FIG. 6 is a start control characteristic diagram of a turbine generator by a conventional turbine speed governor, and FIG. It is a system diagram which shows the connection arrangement with respect to the electric power system of the conventional turbine generator. 10 …… Rotation speed setting device 12 …… Rotation speed secondary setting device, 14 …… Comparison circuit 16 …… Rotation speed controller, 18 …… Adding circuit 20 …… Comparison circuit, 22 …… Valve opening controller 24 …… OR circuit (increase command) 26 …… OR circuit (decrease command), 30 …… Main turbine 32 …… Main generator, 34 …… Main transformer 36 …… Main circuit breaker, 38 …… Bus 40 …… On-site transformer 42 …… Secondary circuit breaker on-site transformer 44 …… Auxiliary equipment, 46 …… Accident circuit breaker for auxiliary equipment 50,56 …… AND circuit, 52 …… Wipeout circuit 54,58,60 …… NOT circuit , 62 …… OR circuit 64 …… Flip-flop circuit

Claims (3)

[Claims] 1. A rotation speed setting signal is obtained by inputting a rotation speed increasing command or a rotation speed decreasing command to a rotation speed setting device, and the rotation speed detection signal, load command signal and valve opening detection signal are sequentially compared and calculated. In the turbine speed governor configured to control the turbine control valve and operate the turbine at a constant rotation speed that matches the set value, an automatic command or In the output line of the OR circuit that inputs the rotation speed reduction command based on the manual command,
A turbine controller characterized by being provided with a control circuit for locking the rotation speed setting value by the lowering command so as not to be less than or equal to the lower limit speed setting value based on the condition of completion of the turbine speed increase and the lower limit speed setting value. Speed setting circuit for high speed equipment. 2. A rotation speed setting circuit according to claim 1, wherein a rotation speed setting device for a turbine speed governor is configured to use an excitation ON operation signal of a turbine generator as a condition for completion of speed increase of a turbine. circuit. 3. A rotation speed setting circuit according to claim 1, wherein the rated speed setting value and the turbine stop signal are used as a condition for completing the speed-up of the turbine. Speed setting circuit.