JP5622198B2 - Synchronous start control device for generator motor - Google Patents

Description

  The present invention relates to a synchronous start control device for a generator motor used in a pumped storage power plant or the like.

  There are a starting motor method, a thyristor starting method, a synchronous starting method and the like as a starting method of the generator motor in the pumped storage power plant. Among these, the synchronous start method is a method in which one of a plurality of generator motors is operated as a driving machine, and the other is started as a driven machine (for example, see Patent Document 1). Hereinafter, a specific example of the conventional synchronous start method will be described with reference to FIGS.

  FIG. 7 is a schematic configuration diagram of a conventional synchronous start control device for a generator motor. In this figure, “A” is added to the end of the reference numeral for components related to the generator motor on the drive side, and “B” is added to the end of the reference sign for components related to the generator motor on the driven machine side. ing. In this conventional example, the other generator motor 1B (driven device side) that functions as a pump motor is started synchronously by the power generation operation of one generator motor 1A (drive device side) that functions as a generator. Is the case.

  The generator motor 1A includes a stator 2A around which an armature winding 3A is wound, and a rotor 4A around which a field winding 5A is wound. The field winding 5A is excited by a field current Ifg supplied via a field breaker 6A from a power supply circuit not shown in the drawing.

  A turbine 8A is connected to the rotor 4A via a shaft 7A. The water turbine 8A has a guide vane 9A, and the amount of inflow water can be controlled by adjusting the opening of the guide vane 9A. Further, a mechanical brake 10A is provided facing the shaft 7A, and the rotation of the shaft 7A, and hence the rotation of the water wheel 8A and the rotor 4A, is restricted by the mechanical brake 10A.

  In addition, since the component which concerns on the generator motor 1B is the same as that of the above, the overlapping description is abbreviate | omitted. The armature winding 3A of the stator 2A and the armature winding 3B of the stator 2B are connected by the power supply path 12 via the circuit breaker 11, and the generator motor 1A performs a power generation operation. The generator motor current I flows.

  FIG. 8 is a block diagram mainly showing the configuration around the excitation circuit of the field winding 5A in FIG. The configuration on the field winding 5B side is the same.

  The converter circuit 13 as a power supply circuit is composed of a semiconductor element such as a thyristor. The converter circuit 13 receives the three-phase AC power from the AC power supply 14 and outputs a DC current by switching control for the semiconductor element of the converter control circuit 15. This direct current flows as field current Ifg to the field winding 5A via the field breaker 6A, the shunt resistor 16, the brush 17, and the like.

  The value of the field current Ifg can be set by the field current setting means 18. The setting signal output from the field current setting means 18 is input to the plus side terminal of the subtractor 21 via the switch 20 controlled by the field breaker closing command means 19. On the other hand, the current flowing through the shunt resistor 16 is detected by the field current detection means 22, and this is input to the minus terminal of the subtractor 21 as a detection signal.

  The subtractor 21 calculates the deviation between the setting signal from the field current setting means 18 and the detection signal from the field current detection means 22 and outputs the deviation signal to the converter control circuit 15. Based on PID control, the converter control circuit 15 controls the output of the converter circuit 13 so that the deviation signal input from the subtracter 21 becomes zero.

  The switch 20 is turned on by a closing command from the field breaker closing command means 19, and this closing command is also output to the field breaker control means 23. The field breaker control means 23 outputs a closing control signal in response to the input of the closing command, and turns on the field breaker 6A.

  The closing control signal from the field breaker control means 23 is also output to the mechanical brake control means 24. The mechanical brake control means 24 has a timer 25, and is set in advance from the time when the input control signal is input (a time sufficient for the field current Ifg to reach the rated set value (100%)). Is measured by the timer 25, a brake release command is output to the mechanical brake 10A. As a result, the mechanical brake 10A releases the restriction on the rotation of the shaft 7A so far.

  The brake release command from the mechanical brake control means 24 is also output to the guide vane control means 26. The guide vane control means 26 starts opening control for the guide vane 9A when this brake release command is input. As a result, the water flowing into the water wheel 8A flows out through the guide vane 9A, and the water wheel 8A rotates the rotor 4A through the shaft 7A.

FIG. 9 is a characteristic diagram showing a transient state near the rise of the field current Ifg. As shown in this figure, the field current Ifg increases according to the following equation (1) after the field breaker 6A is turned on, and becomes substantially equal to E / R after a certain time. Here, E is the output voltage of the converter circuit 13, R is the resistance of the entire excitation circuit of the field winding 5A, L is the inductance of the field winding 5A, and t is time.
Ifg = (E / R). {1-exp (-Rt / L)} (1)

  Next, the operation of the conventional apparatus configured as described above will be described based on the time chart of FIG. At time t0, the mechanical brakes 10A and 10B are in the on state, that is, the brake operating state, and the rotation of the shafts 7A and 7B is restricted. Then, after the circuit breaker 11 of the power supply path 12 is turned on at time t1 to start the synchronous start, a turn-on command is output from the field breaker turn-on command means 19 at time t2, and the switch 20 is turned on. The field breakers 6A and 6B are turned on via the field breaker control means 23.

  After the field breakers 6A and 6B are turned on, a setting signal is output from the field current setting means 18, and based on the deviation between this setting signal and the detection signal of the field current detection means 22, the converter control circuit 15 PID control is started for the converter circuit 13. As a result, field currents Ifg and Ifm begin to flow through the field windings 5A and 5B. The changing state of the field currents Ifg and Ifm at this time is as shown in FIG. 9 and the equation (1).

  The mechanical brake control means 24 inputs a closing control signal from the field breaker control means 23 at time t2, and then outputs a brake release command at time t3 when the timer 25 measures the lapse of the set time. As a result, the mechanical brakes 10A and 10B are turned off, that is, the brake is released. Then, the guide vane control means 26 starts opening control for the guide vane 9A when the mechanical brake control means 24 outputs a brake release command at time t3.

  At time t4 after the opening degree control of the guide vane 9A is started at time t3, the water turbine 8A, the shaft 7A, and the rotor 4A, that is, the generator motor 1A, start rotating, and the generator motor 1A generates power toward the generator motor 1B. The inter-motor current I begins to flow. At time t5, the generator motor 1B also starts rotating, and the synchronous start is completed.

JP 2004-48990 A

  However, in the conventional apparatus, as shown in the regions R1 and R2 of the current I between the generator motors in the lowermost stage in FIG. 10, a large current fluctuation occurs, which makes it difficult to smoothly pull in the generator motor 1B. Has occurred.

  That is, in the process until the field breakers 6A and 6B are turned on at time t2 and the field currents Ifg and Ifm start to flow through the field windings 5A and 5B and reach 100% (rated setting value), the stator 2A. , 2B, a voltage is induced in the armature windings 3A, 3B. At this time, the inter-generator motor current I begins to flow in the region R1 due to the potential difference generated between the armature windings 3A and 3B. However, since the inter-generator-motor current I at this time changes slowly and becomes close to direct current, The iron cores of the stators 2A and 2B are DC magnetized.

  Therefore, until a current in the direction opposite to the DC magnetized current of these iron cores flows and demagnetizes in these iron cores due to the increase in the rotational speed of the rotor 4A, the three-phase AC voltage is applied to the armature windings 3A and 3B. It will not be induced correctly. Therefore, even if the generator motor 1A starts rotating after time t4, the generator motor 1B does not start rotating immediately, but finally starts rotating at time t5. That is, during the period from time t4 to time t5, the generator motor 1B side is started with the rotor 4B being constrained, so the generator-motor current I in the region R2 greatly fluctuates.

  As described above, the DC magnetization is generated in the stator side iron core due to the fluctuation of the generator-motor current I in the region R1, and as a result, the generator-motor current I further fluctuates in the region R2. . Therefore, in order to suppress the current fluctuation in the region R2 as much as possible, it is important to suppress the current fluctuation in the region R1 as much as possible.

  In addition, as for the current fluctuation in the region R1, the level of the current fluctuation may become very large depending on the stop position on the rotor side.

  That is, at time t2, the mechanical brakes 10A and 10B are braked and the field breakers 6A and 6B are turned on. At this time, as shown in FIGS. 11 (a), (b) and (c) When any rotor magnetic pole is directly facing any of the U-phase, V-phase, and W-phase of the armature winding, the induced voltage of the armature winding is maximized and the generator-motor current I is very large. Become. The increase in the generator-motor current I at this time may cause a rotational torque exceeding the binding force of the mechanical brakes 10A and 10B in the rotors 4A and 4B, thereby increasing the induced voltage of the armature winding.

  The present invention has been made in view of the above circumstances, and provides a synchronous start control device for a generator motor that can suppress a level of oscillation generated in a current between generator motors and perform a smooth synchronous start. It is aimed.

  As a means for solving the above-mentioned problems, the invention according to claim 1 is characterized in that a generator operation of one generator motor among a plurality of generator motors having a stator side armature winding and a rotor side field winding is provided. The other generator motor, which is the starting target, is synchronously started, and the rotation of both generator motors is restrained by a mechanical brake during this synchronous start, and the field current of both generator motors is at a predetermined level. In the synchronous start control device for a generator motor that releases the restraint by the mechanical brake after reaching the set value, and synchronizes the rotation speeds of the two generator motors, the field current of the two generator motors is set to the set value of the predetermined level. It is characterized by comprising a change rate limiting means for limiting the current change rate until it reaches.

  According to a second aspect of the present invention, in the first aspect of the present invention, the set value of the predetermined level of the field current of the two generator motors is a set value corresponding to the starting torque.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the arrival of the field current to a set value at a predetermined level is discriminated by measuring the elapsed time from when the field breaker is turned on by a timer means. Or determining based on current detection by the field current detection means.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, a field voltage is controlled instead of the field current control.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the restriction by the mechanical brake is released for a predetermined time at the start of the synchronous start, and the field breaker is released during the release period. To start supplying current to the field winding, and after a predetermined time has elapsed, the mechanical brake is again restrained until the field current reaches the set value of the predetermined level. .

  According to the present invention, it is possible to suppress the level of oscillation generated in the generator-motor current and perform a smooth synchronous start.

The synchronous start control apparatus of the generator motor which concerns on the 1st Embodiment of this invention. The time chart for demonstrating operation | movement of 1st Embodiment. The block diagram which shows the principal part structure of the synchronous start control apparatus of the generator motor which concerns on the 2nd Embodiment of this invention. The time chart for demonstrating operation | movement of 2nd Embodiment. The block diagram which shows the structure of the mechanical brake control means 24 'which is the principal part of the 3rd Embodiment of this invention. The time chart for demonstrating operation | movement of 3rd Embodiment. The schematic block diagram of the synchronous start control apparatus of the conventional generator motor. FIG. 8 is a block diagram mainly showing a configuration around an excitation circuit of a field winding 5A in FIG. 7; The characteristic view which shows the transient state of the vicinity of the rise of the field current Ifg. The time chart for demonstrating operation | movement of a conventional apparatus. It is explanatory drawing about the subject of a conventional apparatus, and shows the state which the stop position of a rotor magnetic pole has faced the armature winding.

  FIG. 1 is a block diagram showing a main configuration of the synchronous start control device for a generator motor according to the first embodiment of the present invention. 1 is different from FIG. 8 in that a change rate limiting means 27 is interposed between the field current setting means 18 and the switch 20.

  The rate-of-change limiting unit 27 limits the rate of change of the setting signal output from the field current setting unit 18 to a certain level or less, and thereby the field currents Ifg and Ifm flowing in the field windings 5A and 5B. It is intended to avoid sudden changes.

  Next, the operation of the first embodiment configured as described above will be described based on the time chart of FIG. At time t0, the mechanical brakes 10A and 10B are in the on state, that is, the brake operating state, and the rotation of the shafts 7A and 7B is restricted. Then, after the circuit breaker 11 of the power supply path 12 is turned on at time t1 to start the synchronous start, a turn-on command is output from the field breaker turn-on command means 19 at time t2, and the switch 20 is turned on. The field breakers 6A and 6B are turned on via the field breaker control means 23.

  After the field breakers 6A and 6B are turned on, a setting signal is output from the field current setting means 18. The change rate of the setting signal is limited by the change rate limiting means 27. The converter control circuit 15 starts PID control on the converter circuit 13 on the basis of the deviation between the setting signal whose rate of change is limited and the detection signal of the field current detection means 22. As a result, field currents Ifg and Ifm begin to flow through the field windings 5A and 5B.

  As apparent from comparison between FIG. 2 and FIG. 10, the field currents Ifg and Ifm are gradually increased in FIG. 2, and therefore, a set value (for example, a predetermined level) from time t2 is obtained. It takes a long time to reach the rated set value (100%). Here, the set value of the predetermined level is at least a field current equivalent to the starting torque.

  After the mechanical brake control means 24 inputs the closing control signal from the field breaker control means 23 at time t2, the timer 25 is longer than the case of FIG. 10 in consideration of the set time (influence of the change rate limiting means 27). The brake release command is output at time t3 when the elapsed time is measured. As a result, the mechanical brakes 10A and 10B are turned off, that is, the brake is released. Then, the guide vane control means 26 starts opening control for the guide vane 9A when the mechanical brake control means 24 outputs a brake release command at time t3.

  At time t4 after the opening degree control of the guide vane 9A is started at time t3, the water turbine 8A, the shaft 7A, and the rotor 4A, that is, the generator motor 1A, start rotating, and the generator motor 1A generates power toward the generator motor 1B. The inter-motor current I begins to flow. At time t5, the generator motor 1B also starts rotating, and the synchronous start is completed.

  As apparent from the comparison between FIG. 2 and FIG. 10, the swing level in the region corresponding to the region R1 in FIG. Therefore, the degree of direct current magnetization of the stator side iron core is also reduced, and the oscillation level is greatly reduced even in the region corresponding to the region R2. Therefore, the synchronous starting of the generator motor 1B after time t5 can be performed smoothly.

  As described above, according to the first embodiment, by providing the rate-of-change limiting means 27, the field currents Ifg and Ifm are gradually raised, so that the level of fluctuation generated in the generator-motor current is suppressed. Thus, it is possible to perform a smooth synchronous start.

  FIG. 3 is a block diagram showing the main configuration of the synchronous start control device for the generator motor according to the second embodiment of the present invention. The configuration of FIG. 3 is obtained by replacing the rate-of-change limiting unit 27 in FIG. 1 with a rate-of-change limiting unit 28. However, because of the space of the drawing, other configurations shown to the right and below the switch 20 in FIG. The component is omitted.

  The change rate limiting means 28 includes a field current setting means 29 for outputting a field current setting signal corresponding to the starting torque, and a changeover switch 30 for switching setting signals output from the field current setting means 18 and 29. , And a set value switching control means 31 for performing switching control on the selector switch 30 by inputting a closing command from the field breaker closing command means 19 and a rotation number detection signal on the rotor 4B side.

  Next, the operation of the second embodiment configured as described above will be described based on the time chart of FIG. At time t0, the mechanical brakes 10A and 10B are in the on state, that is, the brake operating state, and the rotation of the shafts 7A and 7B is restricted. Then, after the circuit breaker 11 of the power supply path 12 is turned on at time t1 to start the synchronous start, a turn-on command is output from the field breaker turn-on command means 19 at time t2, and the switch 20 is turned on. The field breakers 6A and 6B are turned on via the field breaker control means 23.

  The set value switching control means 31 receives the closing command from the field breaker closing command means 19 at this time, and switches the contact of the changeover switch 30 that has been in the neutral position to the a side. As a result, the setting signal from the field current setting means 29 is input to the subtractor 21 via the changeover switch 30 and the switch 20. The subtractor 21 calculates the deviation between this setting signal and the detection signal from the field current detection means 22 and outputs the deviation signal to the converter control circuit 15. The converter control circuit 15 starts PID control on the converter circuit 13 based on the input deviation signal. As a result, the field currents Ifg and Ifm begin to flow through the field windings 5A and 5B, but the upper limit of the field currents Ifg and Ifm is suppressed to a level corresponding to the starting torque that is one step lower than the rated set value. .

  After the mechanical brake control means 24 inputs the closing control signal from the field breaker control means 23 at time t2, the timer 25 is sufficient for the set time (field currents Ifg, Ifm to reach a level corresponding to the starting torque). The brake release command is output at time t3 when the elapsed time is measured. As a result, the mechanical brakes 10A and 10B are turned off, that is, the brake is released. Then, the guide vane control means 26 starts opening control for the guide vane 9A when the mechanical brake control means 24 outputs a brake release state at time t3.

  At time t4 after the opening degree control of the guide vane 9A is started at time t3, the water turbine 8A, the shaft 7A, and the rotor 4A, that is, the generator motor 1A, start rotating, and the generator motor 1A generates power toward the generator motor 1B. The inter-motor current I begins to flow. At time t5, the generator motor 1B also starts rotating, and the synchronous start is completed.

  As in the case of FIG. 2, the generator-motor current I at this time is greatly reduced in the swing level in the region corresponding to the region R1 in FIG. 10, and therefore also in the region corresponding to the region R2. The level has been greatly reduced. Then, after time t5, the generator motor 1B also starts rotating, and the synchronous start is smoothly performed.

  When the set value switching control means 31 determines from the rotational speed detection signal of the rotor 4B that the generator motor 1B has been synchronously started, it switches the contact of the changeover switch 30 from the a side to the b side at time t6. As a result, the setting signal from the field current setting means 18 is input to the subtracter 21 via the changeover switch 30 and the switch 20 this time. Therefore, the levels of the field currents Ifg and Ifm flowing in the field windings 5A and 5B are raised to the level equivalent to the rated current (100%).

  In the first embodiment, the rate of change until the rated current is reached by gradually and continuously raising the field currents Ifg and Ifm by the function of the rate-of-change limiting unit 27 is configured. In the embodiment, the change rate limiting means 28 divides the current levels of the field currents Ifg and Ifm into two stages corresponding to the starting torque and equivalent to the rating (100%), and limits the change rate stepwise. It is said. Therefore, even with the configuration of the second embodiment, it is possible to suppress the level of oscillation generated in the current between the generator motors and perform a smooth synchronous start.

  In the first and second embodiments described above, the field currents Ifg and Ifm are set to the predetermined level (equivalent to the rated set value in the first embodiment and the starting torque in the second embodiment). When the set value is reached (that is, when the restraints of the mechanical brakes 10A and 10B are released), a sufficient time has elapsed since the mechanical brake control means 24 inputs the input command from the field breaker control means 23. This is determined based on the measurement of the timer 25 and the brake is released. However, the brake may be released based on the input of the detection signal from the field current detection means 22.

  In the first embodiment and the second embodiment, the synchronous start control is performed by controlling the field current. However, it is also possible to perform the synchronous start control by controlling the field voltage. In this case, the “field current” and “current change rate” in the first and second embodiments are read as “field voltage” and “voltage change rate”.

  Next, a third embodiment of the present invention will be described. In the third embodiment, a function for stabilizing the magnetic pole position of the rotor is added to the mechanical brake control means 24 in the first or second embodiment.

  FIG. 5 is a block diagram showing the configuration of the mechanical brake control means 24 ', which is the main part of the third embodiment. The mechanical brake control means 24 ′ is the same as the mechanical brake control means 24 in FIG. 1 or FIG. 8 since the input control signal from the field breaker control means 23 from the field breaker control means 23 is input. Although it has a timer 25 for measuring the set time, it further stabilizes the magnetic pole position for measuring the time required for stabilizing the magnetic pole position of the rotor from the time when the synchronous start start command is input. A timer 32 is provided. The brake release command and the brake command output from the mechanical brake control unit 24 ′ to the mechanical brake 10A (or 10B) are sent to the guide vane control unit 26 in the same manner as the mechanical brake control unit 24 in FIG. 1 or FIG. Although output, the mechanical brake control means 24 ′ of this embodiment is also output to the field breaker input command means 19.

  Next, the operation of the third embodiment will be described based on the time chart of FIG. However, in the time chart of FIG. 6, only the operation in the vicinity of time t20 to t21 which is different from FIG. 2 will be described, and the description of the other parts will be omitted because it is the same as FIG.

  The circuit breaker 11 of the power supply path 12 is turned on at the time t1 to start the synchronous start. At this time, the mechanical brake control means 24 ′ receives a synchronous start start command from a synchronous start start command output means (not shown). When the time t20 after the time t1 is reached, the brake of the mechanical brake 10A is released. The magnetic pole position stabilization timer 32 measures the time for stabilizing the magnetic pole position, that is, the time t20 to t21, and activates the brake to the mechanical brake 10A again at the time t21. Therefore, the magnetic pole of the rotor 4A can be moved to a stable position from time t2 when the field breaker 6A is turned on to time t21, which is the time until the mechanical brake 10A is activated again.

  That is, before the time t20 when the rotation of the shaft 7A is restrained, as shown in FIG. 11, any rotor magnetic pole faces the U phase, V phase, or W phase of the armature winding. There is a possibility that it is in a state. In such a state, if the field current is increased to the rated set value while restricting the rotation of the rotor, the induced voltage of the armature winding becomes large, and the generator-motor current I in FIG. As shown in the region R1, the current fluctuation increases.

  Therefore, in the third embodiment, when the field breaker 6A is turned on, the mechanical brake 10A is released for a short period t20 to t21 to make the rotor 4A free. Thus, if a period for making the rotor 4A free is provided, even if the magnetic pole of the rotor 4A is held at the worst position as shown in FIG. During the period t2 to t21 in which this free state is maintained after 6A is turned on, the magnetic pole of the rotor 4A is away from any of the U-phase, V-phase, and W-phase of the armature winding, that is, stable. It can be moved automatically to the correct position by the action of electromagnetic force. Therefore, the swing level at the location corresponding to the region R1 of the inter-generator-motor current I in FIG. 10 and the swing level at the location corresponding to the region R2 can be further reduced.

1A: One generator motor (generator)
1B: The other generator motor (pump motor)
2A, 2B: Stator 3A, 3B: Armature winding 4A, 4B: Rotor 5A, 5B: Field winding 6A, 6B: Field breaker 7A, 7B: Shaft 8A, 8B: Water wheel 9A, 9B: Guide vanes 10A, 10B: Mechanical brake 11: Circuit breaker 12: Power supply path 13: Converter circuit 14: AC power supply 15: Converter control circuit 16: Shunt resistor 17: Brush 18: Field current setting means 19: Field breaker Input command means 20: switch 21: subtractor 22: field current detection means 23: field breaker control means 24, 24 ': mechanical brake control means 25: timer 26: guide vane control means 27: change rate limiting means 28 : Change rate limiting means 29: field current setting means 30: changeover switch 31: set value change control means 32: magnetic pole position stabilization timer Ifg, Ifm: field current I: power between generator motor

Claims (4)

Among the plurality of generator motors having the stator side armature winding and the rotor side field winding, the other generator motor to be started is synchronously started by the power generation operation of one generator motor, and At the time of this synchronous start, the rotation of both generator motors is restrained by the mechanical brake, and after the field current of both generator motors reaches the set value of the predetermined level, the restraint by the mechanical brake is released and both generator motors are released. In the synchronous start control device for the generator motor that synchronizes the rotation speed of
Change rate limiting means for limiting the rate of change of current until the field currents of the two generator motors reach the set value of the predetermined level;
Equipped with a,
At the start of the synchronous start, the restraint by the mechanical brake is released for a predetermined time, and during this release period, the field breaker is turned on to start supplying current to the field winding. Is again restrained by mechanical braking until the field current reaches the set value of the predetermined level,
A synchronous start control device for a generator motor. The set value of the predetermined level of the field current of the two generator motors is a start torque equivalent set value,
The synchronous start control device for a generator motor according to claim 1. Whether the field current reaches a set value at a predetermined level is determined by measuring the elapsed time from when the field breaker is turned on by the timer means, or based on current detection by the field current detecting means. ,
The synchronous start control device for a generator motor according to claim 1 or 2. Instead of controlling the field current, the field voltage is controlled.
The synchronous start control device for a generator motor according to any one of claims 1 to 3.

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