JP5473166B2 - Control device for variable speed pumped storage power generator - Google Patents

Description

  The present invention relates to a control device for a variable speed pumped storage power generation device using an AC excitation synchronous machine, and more particularly to a control device for a variable speed pumped storage power generation device capable of quickly performing an operation when switching from pumping start operation to pumping operation. It is.

  A variable speed pumped storage power generation system that applies an AC excitation synchronous machine to a pumped storage power generation system can control output at higher speed and higher accuracy than conventional synchronous machines.

  This variable speed pumped-storage power generator includes a generator motor in which an armature winding is AC-excited, and a pump turbine directly connected coaxially with the armature winding shaft of the generator motor. The generator motor is a generator, and the pump turbine is Power generation operation is performed by using a water turbine, pumping operation is performed by using a generator motor as a motor and a pump turbine as a pump.

  In power generation operation and pumping operation, it is possible to adjust the AC secondary excitation of the armature winding of the generator motor and perform so-called sliding operation so that it can be operated at a rotation speed suitable for each operation mode. Therefore, highly efficient operation can be realized.

  Furthermore, since appropriate quick switching can be performed between the power generation operation and the pumping operation, it can greatly contribute to the stable operation of the power system. For example, when power shortage occurs in the power system, if the pumping operation is canceled and the operation is switched to the power generation operation, the electric power that is twice the operation capacity can be adjusted. This is an effect that can also be achieved when the power surplus is canceled and the power generation operation is canceled and switched to the pumping operation.

  The ability to quickly switch the operation mode can greatly contribute to stable operation of the power system. Of these switching operations, it is suitable that the AC-excited synchronous machine is operated as a synchronous machine characteristic operation at the switching stage from power generation to pumping, that is, at the power generation stop / pumping start stage. For this reason, the variable speed pumped storage power generator is provided with a synchronous machine characteristic operation mode to realize a safe and operable power generation stop and pumping start.

  Thus, it is desirable to perform synchronous machine characteristic operation in the pumping start stage, and to perform slip operation in the subsequent pumping operation, and for this purpose, as proposed in Patent Document 1, At the time of shifting to operation, it is necessary to perform an adjustment operation so that the phase is continuous when shifting from synchronous machine characteristic operation to sliding operation. As a result, the system can be prevented from becoming unstable at the time of switching.

Japanese Patent No. 3050936 (Japanese Patent Laid-Open No. 5-284798)

  Generally, the phase error in the synchronous machine characteristic operation at the start of pumping is different from the phase error in the sliding operation during the pumping operation. In order to make the operation of the variable speed pumped storage power generator unstable depending on the magnitude of this phase error, in Patent Document 1, when switching from the synchronous machine characteristic operation mode to the sliding operation mode after completion of pumping start, an excitation current command By adjusting the q-axis current component Iq input to the arithmetic unit, the phase before and after switching is made continuous.

  However, this operation of adjusting the q-axis current component Iq after completion of pumping start or the like takes time, so the transition from the synchronous machine characteristic operation mode to the sliding operation mode cannot be performed smoothly.

  An object of the present invention is to improve the operability of the variable speed pumped storage power generation system by executing this mode switching in a shorter time.

  In the present invention, the primary winding is connected to the AC system, the rotary shaft is directly connected to the pump turbine, and the secondary winding is excited by the frequency converter, and the automatic active power control device An excitation current command calculation device that obtains a q-axis current component command Iq to be given and a d-axis current component command Id determined by the automatic voltage control device and combines with a phase signal to obtain an excitation current command value for the frequency converter; A slip phase calculator that obtains a slip phase signal as the difference between the voltage phase of the system and the rotor electrical machine angle of the AC excitation synchronous machine, a transmitter output calculator that obtains a synchronous excitation phase signal from the target frequency signal, and an AC excitation synchronous machine In the slip operation mode, the slip phase signal of the slip phase calculator is applied as a phase signal to the excitation current command calculator, and in the synchronous characteristics operation mode of the AC excitation synchronous machine. In a control device for a variable speed pumped storage power generation device comprising an output calculator for supplying an excitation current command calculation device as a phase signal with a synchronous excitation phase signal of a transmitter output calculator, pumping with an AC excitation synchronous machine as a synchronous characteristic operation mode Correction unit that corrects the synchronous excitation phase signal of the transmitter output calculator to a value close to the slip phase signal at the pumping start stage when starting and then switching to the pumping operation with the AC excitation synchronous machine as the slip operation mode Is provided.

  The correction unit obtains the phase error as an inverse trigonometric function of the difference signal between the slip phase signal and the synchronous excitation phase signal, and multiplies this by a value of 1 or less when in the synchronous characteristic operation mode to obtain the trigonometric function. It is preferable to perform a phase shift calculation of the excitation phase signal.

  In the variable speed pumped storage power generation apparatus, switching from the synchronous machine characteristic operation to the sliding operation can be performed in a short time and smoothly, so that the operability of the variable speed pumped storage power generation apparatus is improved.

It is a block diagram which shows one Example of the phase error correction method in this invention. [BRIEF DESCRIPTION OF THE DRAWINGS] It is a block diagram of the pumped-storage power generation system with which the Example of the alternating current excitation electric power generating apparatus by this invention was applied.

  Hereinafter, a variable speed pumped storage power generator according to the present invention will be described in detail with reference to the drawings.

  First, the configuration of the variable speed pumped storage power plant and its control system will be described with reference to FIG.

  The main circuit configuration of the variable speed pumped storage power generator will be described. The main circuit is mainly composed of an AC excitation synchronous machine 5, a pump turbine 4, and a frequency converter 6. The AC excitation synchronous machine 5 has a primary winding connected to the AC system 1 via a synchronous circuit breaker 2 and a main transformer 3, and a rotating shaft directly connected to the pump turbine 4. In addition, the armature winding that is the secondary winding of the AC excitation synchronous machine 5 is wound on the rotating shaft and excited by the frequency conversion device 6. The frequency converter 6 includes three sets of 12-phase non-circulating current type cycloconverters 8 and an excitation transformer 7. The excitation transformer 7 is connected to the connection point of the main transformer 3 and the synchronous circuit breaker 2. Connected to receive power.

  Next, as the final operating end of the control system, the amount of excitation of the armature winding is controlled by controlling the ignition phase of the cycloconverter. The excitation amount is determined by the automatic active power control device 15 (APR) and the automatic voltage control device 16 (AVR). The automatic active power control device 15 (APR) compares the active power target value and the active power of the AC system 1 detected by the output sensor 28, and uses the output to compare the q-axis current component via the Iq controller 22. Command Iq is obtained. The automatic voltage control device 16 (AVR) compares the voltage target value with the voltage of the AC system 1 detected by the output sensor 28 to obtain a d-axis current component command Id.

  The current command (Iq, Id) is given to the excitation current command calculation device 27 and is combined with the slip phase signal θs from the slip phase detector 12 to become an excitation current command value for each phase of the cycloconverter 8. The excitation current control device 23 is configured to output a firing angle command to the automatic pulse phase shifter 24 so that the excitation current detection value and the excitation current command value match.

  Here, the excitation current command calculating device 27 will be described in more detail. This is a biaxial current in which the amplitude and phase of the three-phase alternating current command rotating together with the slip phase signal θs from the slip phase detector 12 are orthogonal to each other. It is adjusted by the command (Iq, Id). Thus, in this system, the AC excitation current command value is created from the reference slip phase signal θs.

  The slip phase detector 12 includes two sets of detection systems for calculating the slip phase signal θs. One set of detection systems is a voltage transformer 9 and a system voltage positive phase calculator 11 for detecting the voltage phase θv of the AC system 1, and the other detection system is a rotor electrical machine angle θr of the AC excitation synchronous machine 5. These are the resolver device 10 and the rotational phase normal phase calculator 26. The slip phase calculator 13 calculates a slip phase θs (= θv−θr) as a difference between the voltage phase θv and the rotor electrical machine angle θr, and calculates a phase signal that changes in a sinusoidal shape with a constant amplitude together with the slip phase θs. The system voltage positive phase calculator 11 and the rotational phase positive phase calculator 26 perform a rotation direction switching calculation by an external digital input “pumping / power generation”.

  Although two diagonal lines are described in the output line from the slip phase calculator 13 in FIG. 2, this means a three-phase AC signal, and this content is the slip phase signal θs. The slip phase calculator 13 also includes a slip frequency calculator 14, a phase compensation amount calculator 17, and a phase compensation calculator 18, which are not directly related to the present invention and are not described here. In short, however, the slip phase signal θs of the slip phase calculator 13 is guided to the output calculator 19. In FIG. 2, the symbol 112 is added to the slip phase signal θs led to the output computing unit 19.

  On the other hand, two diagonal lines are also shown in the output line from the transmitter output computing unit 20 to the output computing unit 19, which means a three-phase AC signal, and this content is a synchronous excitation phase signal. 111.

  In this way, two sets of phase signals are input to the output computing unit 19, and the slip phase signal 112 is selected when the AC excitation synchronous machine is in sliding operation, and the synchronization excitation phase signal 111 is selected when performing synchronous characteristic operation. Is selected as the excitation reference phase in the excitation current command calculation device 27. Needless to say, the slip phase signal 112 is a variable phase signal, and the synchronous excitation phase signal 111 is a fixed phase signal.

  In the present invention, the smooth switching from the pumping start stage to the pumping operation is intended, but in the pumping start stage, the synchronous excitation phase signal 111 is selected to perform the synchronous characteristic operation, and then the sliding operation is performed in the pumping operation. Therefore, the slip phase signal 112 is switched to. However, the synchronous excitation phase signal 111 is generally not equal to the slip phase signal 112. For this reason, the phase alignment adjustment is performed by the Iq controller 22 after shifting to the sliding operation mode in Patent Document 1, so that there is a problem that it takes time to stabilize.

  In the present invention, the operation of bringing the synchronous excitation phase signal 111 closer to the slip phase signal 112 during the synchronous characteristic operation at the pumping start stage is started from a position close to the slip phase signal 112 when the pumping operation is started thereafter. To make a stable transition. The above operation of the present invention is performed in the transmitter output computing unit 20 that creates the synchronous excitation phase signal 111.

  FIG. 2 is an embodiment of the present invention in which the transmitter output calculator 20 and its peripheral circuits are described. A target frequency signal 110 is given to the transmitter output calculator 20 from the state switching logic 25 of FIG. 1 and is set as a synchronous excitation phase signal 111 via the synchronous excitation transmitter 108 and the phase shift calculator 109. The synchronous excitation phase signal 111 thus obtained is a fixed phase signal. The synchronous excitation phase signal 111 from the phase shift calculation unit 109 is corrected by the phase compensation amount calculation unit 17 and the phase compensation calculation unit 18, but the function of this part is not directly related to the present invention. Omitted.

  The other input part of the phase shift calculation unit 109 is a part related to the present invention, and the output of the synchronous excitation transmitter 108 is corrected by this signal. This correction is performed according to the output of the phase error calculation unit 101. The phase error calculation unit 101 is supplied with the slip phase signal 112 and the synchronous excitation phase signal 111, and a phase signal difference signal 29 based on the slip phase signal 112 is derived. Further, in the inverse trigonometric function calculation unit 102, an inverse trigonometric function of the phase signal is obtained and used as a phase error signal expressed in magnitude. The phase error signal represented by the magnitude is multiplied by an appropriate coefficient by the multiplier 104 and restored to the phase signal again by the trigonometric function calculation unit 107. In the phase shift calculation unit 109, the reference phase given by the synchronous excitation transmitter 108 is shifted by the amount corresponding to the correction phase given by the trigonometric function calculation unit 107.

  In the present invention, the gain of the multiplier 104 is switched by the gain switch 103. The gain in the sliding operation mode is “1”, but in the synchronous machine characteristic operation mode, the gain is “KD” which is smaller than “1”.

  The circuit of the present invention configured as described above generally functions as follows. First, in the pumping start stage, in order to perform the synchronous machine characteristic operation, the gain switch 103 multiplies the phase error signal 29 by, for example, 0.1 as “KD” having a value smaller than “1”. As a result, the synchronous excitation phase signal 111 determined by the target frequency signal 110 is corrected to a value close to the slip phase signal 112 by shifting the phase signal by an amount corresponding to 0.1 and fed back to the phase error calculation unit 101. Is done. Further, the phase error signal 29 at this time is multiplied by 0.1, and the synchronous excitation phase signal 111 is corrected to a value close to the slip phase signal 112 by shifting the phase signal by an amount corresponding to 0.1. Thereafter, by repeating this process, the synchronous excitation phase signal 111 given to the output computing unit 19 approaches the slip phase signal 112.

  It is sufficient that the synchronous excitation phase signal 111 and the slip phase signal 112 are close to each other to some extent. As a result, the phase error is small when shifting to the pumping operation mode, so that stable and prompt switching can be performed. Further, although depending on the magnitude of the gain KD, this correction operation is completed in a relatively short period of the pumping start stage, and as a result, the AC excitation synchronous machine 5 is in the fixed phase synchronous excitation phase close to the slip phase signal 112. The operation is continued by the signal 111.

  The above description of the gain operation was performed when the synchronous characteristic operation mode 31 was performed. However, in the sliding operation mode 30 in the circuit of FIG. 1, the gain switch 103 sets the gain “1” to the multiplier 104. This is given to the phase error 29. As a result, in the phase shift calculation 109, the phase error 29 is corrected as it is, and the synchronous excitation phase signal 111 has the same form as when the slip phase signal 111 is output. In this way, standby for switching the phase continuation from the slip operation mode to the synchronous machine characteristic operation mode is realized.

  According to the present invention, the switching from the pumping start to the pumping operation can be performed quickly and stably, so that it can be widely used as a variable speed pumped storage power generation device.

DESCRIPTION OF SYMBOLS 1 AC system 2 Synchronous circuit breaker 3 Main transformer 4 Pump turbine 5 AC excitation same equipment 6 Frequency converter 7 Excitation transformer 8 Semiconductor power converter (cycloconverter)
9 Voltage transformer 10 Resolver device 11 System voltage positive phase calculator 12 Slip phase detector 13 Slip phase calculator 14 Slip frequency calculator 15 Automatic active power controller (APR)
16 Automatic voltage controller (AVR)
17 phase compensation calculator 18 phase compensation calculator 19 output calculator 20 oscillator output calculator 21 Iq adjustment calculator 22 Iq controller 23 excitation current controller 24 automatic pulse phase shifter (APPS)
25 State switching logic unit 26 Rotation phase normal phase computing unit 27 Excitation current command computing unit 28 Output sensor 29 Phase error 30 Sliding operation mode 31 Synchronous machine characteristic operation mode 101 Phase error computing unit 102 Inverse trigonometric function computing unit 103 Gain switching unit 107 Trigonometric function calculation unit 108 Synchronous excitation oscillator 109 Phase shift calculation unit 111 Synchronous excitation phase signal 112 Slip phase signal

Claims (2)

An AC excitation synchronous machine in which the primary winding is connected to the AC system, its rotating shaft is directly connected to the pump turbine and the secondary winding is excited by the frequency converter, and the q-axis current component provided by the automatic active power control device A command lq, a d-axis current component command ld determined by the automatic voltage controller, and an excitation current command calculation device for obtaining an excitation current command value for the frequency converter by combining with a phase signal, and a voltage of the AC system A slip phase calculator for obtaining a variable phase slip phase signal as a difference between the phase and the rotor electrical machine angle of the AC excitation synchronous machine, a transmitter output calculator for obtaining a fixed phase synchronous excitation phase signal from a target frequency signal, In the slip operation mode of the AC excitation synchronous machine, the slip phase signal of the slip phase calculator is given to the excitation current command calculation device as the phase signal, In the period characteristic operating mode, the control device configured variable-speed pumped-storage power generator synchronized excitation phase signal of the transmitter output calculator and an output calculator giving the excitation current command calculation unit as the phase signal,
When performing pumping start with the AC excitation synchronous machine as the synchronous characteristic operation mode and then switching to the pumping operation with the AC excitation synchronous machine as the sliding operation mode, in the pumping start stage, synchronous excitation of the transmitter output computing unit is performed. A control device for a variable speed pumped storage power generator, comprising: a correction unit that corrects a phase signal to a value close to the slip phase signal. In the control device of the variable speed pumped storage power generator according to claim 1,
The correction unit obtains a phase error as an inverse trigonometric function of a difference signal between the slip phase signal and the synchronous excitation phase signal, and obtains a trigonometric function by multiplying this by a value of 1 or less when in the synchronous characteristic operation mode. A control device for a variable speed pumped storage power generation device, wherein a phase shift operation of the synchronous excitation phase signal is performed.

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