JPS6236479B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an output control device for a generator. For example, in small-scale power systems or private gas turbine generators, a mechanical limiter is installed to prevent overload operation of the prime mover, but this mechanical limiter (with constant fuel opening) Since there will be a limit output error of approximately 25% (0° to 40°C), the specified limit output (authorized output) will always be
You cannot drive inside. In addition, when the generator load exceeds the output limit, in small-scale factories, it is normal to separate the load or reduce the generator's rotation speed and output voltage manually, so this manual operation is required. Until now, it was not possible to avoid overload operation. This invention was made to eliminate the above-mentioned drawbacks of the conventional technology, and when the generator output exceeds the upper limit of the output limit, this is detected electrically and the rotational speed or output voltage of the generator is reduced. In addition, when the generator output falls below the lower limit of the output limit, it is detected electrically and the rotational speed of the generator is increased or the output voltage is increased (by excitation control), thereby increasing the generator output. To control the output of the generator to bring it within the limited output range when the generator is out of the limited output range, and perform load separation or load transfer during parallel operation without overloading the generator when the load suddenly increases. It is an object of the present invention to provide a generator output control device with a simple configuration that allows the generator to be operated within a limited output at all times. Hereinafter, one embodiment of the present invention will be described with reference to the drawings. In Fig. 1, 1 is a gas turbine, 2 is a three-phase alternating current generator (hereinafter referred to as a generator), 3 and 4 are instrument transformers and alternators, and 5 is a power detector, which is a three-phase alternator of generator 2. It sends out a voltage signal _VX proportional to the output. 6 and 7 are upper limit output and lower limit output setters, respectively, which output the upper limit setting signal V _U and the lower limit setting signal V _L respectively.
(However, V _U =V _L +K, K is a constant).
8 is a comparator which receives the voltage signal _VX and the upper limit setting signal, and outputs when _VX > _VU . 9 is a comparator, which receives the voltage signal V _X and lower limit setting signal V _L ;
It outputs when V _X <V _L. Switching elements 10 and 11 are closed when receiving the outputs of comparators 8 and 9, respectively. R ₁ is a relay for upper limit limit, and switching element 1 is connected between both terminals of relay power supply E.
It is inserted in series with 0. _R2 is a lower limit value limiting relay, and is inserted in series with the switching element 11 between both terminals of the relay power source E. 12 is a generator speed or voltage control device that compares the output of a speed sensor that detects the rotational speed of the gas turbine 1 or a voltage sensor that detects the voltage of the generator 2 (both not shown) with the control command S; The output voltage is controlled by rotational speed control or excitation control of the generator 2 in accordance with the deviation. The control command S is supplied from the command setting device 13. Command setting device 13
is constituted by, for example, a motor potentiometer, and correspondingly decreases and increases the level of the control command S while the decrease command Ca and increase command Co are being input. Decrease command Ca is input via normally open contact R ₁ of relay R ₁ , and increase command Co is input via normally open contact Y of relay Y. The relay Y is incorporated into a return condition relay circuit as shown in FIG. 2, for example. In FIG. 2, X is the normally open contact of the relay X, and Z and are the normally open and normally closed contacts of the relay, respectively. As shown in Figure 3, relays R ₁ and R ₂ have delayed return (OFF) in response to activation (ON) of their contacts, and are given a collective hysteresis operating characteristic to prevent each hunting operation and reduce power generation. It ensures that the machine output is pushed within the specified range, and also turns relay R ₁ off and relay R ₂ on (relay R ₁
Hysteresis is provided between the ON of relay R2 and the OFF of relay _R2 to prevent control hunting from occurring. In the above configuration, when the load on the generator 2 increases rapidly and _the generator output P exceeds _{the upper limit P U of} the limit output, _V is output and the switching element 10 is closed, so the relay _R1 is energized and its normally open contact _R1 is closed (ON). This allows the reduction command
Since Ca is applied to the command setting device 13, the level of the control command S decreases, and the rotational speed or output voltage of the generator 2 begins to decrease, and the power of the generator P decreases. When the generator output P decreases to the upper limit P _U of the limit output, the output of the comparator 8 disappears and the electromagnetic relay R ₁ is deenergized.
Since the relay _R1 has hysteresis operation characteristics, the normally open contact _R1 does not turn off immediately even if V = V _U , but turns off after a certain period of time, so the generator output P is lower than the upper limit output P _U output value _U. When the overload condition is removed and the rated load condition is reached,
Since the generator voltage or speed is decreasing, the generator output P decreases. When the generator output P becomes less than the lower limit P _L of the limited output, V<V _L and the comparator 9 that constitutes the relay operating section outputs an output, the switching element 11 is closed and the relay R ₂ is energized. be done. At this time, the relay X of each relay circuit (Fig. 2) will be reset.
is already energized, so when normally open contact _R2 turns ON, relay Y is energized and normally open contact Y is closed. As a result, the increase command Co is changed to the command setter 13.
In addition to this, the level of the control command S begins to increase, so the rotational speed or output voltage of the generator 2 increases. When the generator output P recovers to the lower limit P _L of the limited output, the output of the comparator 9 disappears and the relay R ₂ is deenergized. Since the relay _R2 has a hysteresis operation characteristic, it does not turn off even when V=V _L , but turns off after a certain period of time. Therefore, the generator output P recovers to an output value _L (approximately the rated speed and rated voltage) that is larger than the lower limit output P _L. Voltage control of the generator 2 is performed when the load is, for example, a lighting load, and speed control is performed when the load is, for example, a pump load. The control command is given as a voltage command in the former case and as a speed command in the latter case, and when overloaded, the level decreases in accordance with the amount of overload, and the generator speed or output voltage correspondingly decreases. However, the generator output is maintained within the limit output. Therefore, even if load separation is delayed, there is no risk of exceeding the limit output, and after load separation, the rotational speed or output voltage is automatically increased to maintain the output limit within the limit output. In this embodiment, a reset condition relay circuit is provided so that relay Y is activated when relay R ₁ is activated _. It can also be configured such that the increase command Co is supplied via the contact _R2 . Next, specific loads will be listed and explained. Now, if the main generator load is electric lights,
Since the lowering limit of the output voltage V of the generator 2 can be set to 5%, the output voltage V can be reduced to 92% of the rated voltage V _0.
% (however, P/P ₀ = (V/V ₀ ) ^1.6 ), ^and 1/
From 0.92=109%, approximately 10% more load is allowed. In addition, if the main load of the generator is the motor (pump), the limit for lowering the rotation speed N (frequency) at which it can continue to operate without any problems while bearing the full load from the prime mover side is 3%. 97 where N is the rated rotation speed N ₀ (frequency)
%, the output P is 91% of the rated output P ₀ (however, P/P ₀ = (N/N ₀ ) ³ ), which is 1/0.91≒
Approximately 10% more pump equipment can be operated than 110%. Therefore, the operating level of the lower limit value limiting relay _R2 , that is, the output level of the lower limit output setting device 7, is set to be 10% or more lower than the operating level of the upper limit value limiting relay _R1 , that is, the output level of the upper limit output setting device 6. ,relay
By setting the hysteresis of R ₂ within 10%, even if relay R ₂ is tripped after overload separation, there is no risk of reintroducing an overload condition, and operation is possible within the limit output up to approximately 110% load. be able to. However, in this case, the level of the control command S, that is, the speed or voltage command, from the command setting device 13 is excessively decreased or increased, and the speed or voltage of the generator 2 exceeds the above-mentioned lowering limit, or conversely, the rated speed Or, in order to prevent a situation in which the voltage is exceeded, as shown in Figure 4,
Contacts L _{S1 and} L _S2 , which open when the speed or voltage command level, the rotational speed of the generator, or the output voltage level decreases to a predetermined level and increases, respectively, are connected in series with the normally open contacts of relay _R1 and relay Y, respectively. Insert into. In addition, the hysteresis of relay _R1 is selected to be small, and the generator output _U when it is OFF is P _U
It is preferable to get close to . Next, a case where the generator 2 is operated in parallel with another generator 2a as a generator whose load is limited (the speed of the generator 2 is controlled) will be described. In Figure 5, both generators are running at rated frequency _R (a+
It is assumed that the generator 2 is being operated under the load of b) (However, at this time, the generator 2 is assumed to be operating near the upper limit of the output limit). The load is (c+d)
, the generator 2 will be overloaded by, for example, the load C, so the level of the control command S will automatically drop to zero, and the rotation speed of the generator 2 will decrease.
The load C is transferred to the other party's generator 2a, but the generator 2a
Since the frequency of also decreases, it becomes stable at a new frequency ' due to the transition of (C - σ). Generator 2 is still overloaded σ
As a result, the level of the control command further decreases to the level C
is all transferred to the other party's generator 2a and becomes stable. In reality, the load is lower than the limit output upper limit by an amount equivalent to the hysteresis of relay _R1 . When the load on the system decreases and relay _R2 is energized, the level of control command S increases and takes on the maximum load. Therefore, generator 2
The overload is automatically transferred to the other generator without causing overload operation. In the above embodiment, relays R ₁ and R ₂ are used to simplify the configuration, but the normally open contact P ₁
The same effect can be obtained even if a non-contact switching element is used in place of P 2 and P ₂ (therefore, Y 2 ) and its switching operation is given hysteresis operation characteristics. As described above, according to the present invention, when the load on the generator exceeds the output limit, the speed or voltage of the generator is automatically reduced in accordance with the amount of overload, and the generated output is maintained within the output limit. Although it has a simple configuration, it can completely prevent overload operation even when load separation is performed manually, and it also greatly reduces the labor of workers as load separation does not require urgency. can be reduced to Furthermore, for loads that allow input fluctuations within a certain range, it is possible to continue operation within the limit output without performing load separation up to a certain overload level, so load separation can be reduced compared to conventional methods. This makes scheduling easier. Also, in the case of parallel operation, although the configuration is much simpler than automatic frequency control devices used in large power systems, load shifting can be performed without overload operation.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing one embodiment of the present invention, Fig. 2 is a return condition relay circuit diagram used in the above embodiment, Fig. 3 is a hysteresis operation characteristic diagram of an electromagnetic relay, and Fig. 4 is a command setting device. The input circuit diagram and the fifth
The figure is a parallel operation characteristic diagram. In the figure, R ₁ and R ₂ ... upper limit value limiting relay and lower limit value limiting relay, 12 ... speed or voltage control device, and 13 ... command setting device. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A speed or voltage control device for a gas turbine generator, a command setting device that supplies a control command to the speed or voltage control device, and a generator output that sets an upper limit setting value of a predetermined output limit range. a relay for limiting the upper limit of the hysteresis operating characteristic that is energized when the output exceeds the lower limit value of the hysteresis operating characteristic; In preparation, while the upper limit value limiting relay and the lower limit value limiting relay are in operation, a level decrease command and a level increase command of the control command are supplied to the command setting device, and the generator output is controlled to be within the output limit range. A generator output control device characterized by: 2. Claim 1, characterized in that the level increase command is supplied to the command setting device by energizing the lower limit value limiting relay on the condition that the upper limit value limiting relay is energized. generator output control device. 3. The generator output control device according to claim 1 or 2, wherein the level width of the control command is limited in accordance with the allowable input fluctuation range of the load.