JP2858748B2 - Idling control method for variable speed hydraulic machine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to an electric operable variable-speed hydraulic machine having a power converter on a primary side or a secondary side and operated at a variable speed, and particularly to an electric power system. The present invention relates to a variable speed hydraulic machine suitable for stabilization. [Prior Art] Known examples of the present invention include: a. S61, National Institute of Electrical Engineers of Japan, No. 1028, “Study on Two-Axis Excitation Current Control System of Generator Motor for Variable Speed Pumped Storage Power Generation System”, “b. Shoin, supervision; Ichiro Enno (Waseda Univ.)) P1-64, 7.5.3, P5-819.9.4 are known. However, the principle and method of the phase control operation of a hydraulic machine are described, but the method of controlling the phase control of a variable-speed hydraulic machine having a power converter and capable of variable-speed operation is not described at all. There is no idea of achieving the active power control at the same time as the phase control, that is, the reactive power control.Moreover, the known example a discloses a two-axis excitation current control method for a generator motor for a variable speed pumped storage power generation system. FIG. 4 is an explanatory view showing the generator / motor 1 The secondary side, that is, the rotor side, was subjected to variable frequency excitation by the power converter 3 (CYC), and the rotation speed of the rotor was made variable while the power frequency on the primary side, that is, the stator side, of the generator / motor was kept constant. It is related to a variable speed generator / motor, and an APR (output control device) of 17 is an output command not shown (that is, an active power command).
An actual output detector 16 compares the output of乍Ra ACR37 commanding value I _g of direct axis current in the active power corresponds to relative (exciting current controller). On the other hand, the AVR 36 (voltage control device) generates a voltage command (not shown) and the actual power generation /
The value of the horizontal axis current equivalent to the voltage to be compared with the motor voltage
Specify id. An ACR (excitation current control device) 37 determines each phase voltage command v in consideration of the actual slip phase angle θ _S detected by the phase detector 7 and the actual phase current im in addition to the above ig and id. 38 is a current detector for the generator / motor, and 40 is a transformer for a three-power converter. By the way, this known example does not mention any control method during the idling operation of the hydraulic machine. In particular, there is no disclosure of the idea of utilizing the characteristic of variable speed to release the energy stored in the inertial effect of the rotating section and to control the active power so as to store the energy therein, thereby contributing to the stabilization of the power system. [Problems to be Solved by the Invention] An object of the present invention is to provide a variable-speed hydraulic machine that enables active power control in the direction of suppressing fluctuations in power system frequency in addition to conventional reactive power control. I do. [Means for Solving the Problems] In order to achieve the above object, the present invention provides a hydraulic machine, a generator or a motor directly connected to the hydraulic machine, and a primary or secondary side of the generator / motor. In a variable-speed hydraulic machine that performs variable-speed operation, the water level of a runner chamber is reduced by using a power converter that has a power converter and detection means that detects a change in the frequency of a power system connected to the primary side of a generator / motor. In the idle running mode in which the runner runs idle, when the frequency of the power system detected by the detection means increases, the rotation speed of the hydraulic machine increases, and when the frequency of the power system decreases, the A control means for lowering the rotation speed is provided. [Operation] According to the variable-speed hydraulic machine of the present invention, it is possible to take in and take out active power at high speed by increasing or decreasing the rotation speed according to the frequency state of the power system. The frequency stability is improved. FIG. 1 is a block diagram showing an embodiment of the present invention. 1
Denotes an induction type generator motor or induction motor that can be used as both a generator and a motor (hereinafter referred to as a generator / motor), 2 is a hydraulic machine directly connected to a rotor of 1 generator / motor, and 3 is a power converter. A cycloconverter for exciting the secondary excitation circuit of the generator / motor 1 for a variable frequency equivalent to the slip, 6 a speed detector for detecting the actual rotational speed N of the hydraulic machine, and 7 a slip phase detector for power generation. / primary that slips phase angle equal to the difference between the secondary side rotational phase of the first generator / motor in terms of voltage phase and the electrical angle of the electric power system of the motor 1 theta detecting the _S. The rotor of the slip phase detector is provided with a three-phase winding connected in parallel with the primary winding of the generator / motor 1, and the stator side of the slip phase detector has a position different by π / 2 in electrical angle on the stator side. One Hall Converter
Pieces be provided, the signal voltage phase of the power system as viewed from the secondary side of the generator / motor 1 match is detected from the Hall converter, it is converted into slips phase angle theta _S. N ₀ is a set speed that determines a steady speed during the idling operation of the hydraulic machine. 30 is an adder for this N ₀ and the actual rotation speed N
To derive the difference ε _Nb . 31 is the speed deviation ε described above
_A speed control unit that constantly sets the deviation ε _Nb to zero with _Nb as an input and gives an active power command p × 1 to the generator / motor so as to ensure the stability of the speed control system of the hydraulic machine. is there. f is the frequency of the power system which the generator / motor is connected, f ₀ is the rated frequency Δf indicates the deviation of f and f _0. 24 is decreased to the inexact differential circuit gain k ₁ time constant T ₁ at irregular change rate arithmetic unit. Numeral 25 denotes a dead zone element that increases or decreases in accordance with these overshoots when the speed change rate output from the speed change rate calculation unit 24 becomes higher than a predetermined value on the plus side or lower than a predetermined value on the minus side. The active power command p × 2 is output. Note that this p × 2 acts to increase the drive output of the generator / motor (load when viewed from the power system) when f rises sharply and Δf rises sharply, and on the contrary, it decreases the drive output when f falls sharply. It acts to help stabilize the power system. FIG. 3 shows an alternative to the circuit of the part from Δf to p × 2. In this case, simply when the frequency deviation Δf itself becomes more than a plus predetermined value or becomes less than a minus predetermined value, it depends on the overshoot amount. To respond. FIG. 2 is a block diagram showing details of the speed control unit 31. 31b is for controlling St. the output of the generator / motor to pull back the N continues to grow the output p × 1 in the desired direction if I remaining connexion deviation epsilon _Nb i.e. N in the integral element even slightly N ₀ . 31a is a proportional element for improving the stability of the N control system. Reference numeral 41 denotes a dead band element for detecting the overshoot amount when N attempts to overshoot beyond the upper limit or lower limit of the variable speed band without producing any output as long as N stays within the variable speed band. Element. Reference numeral 42 denotes an N kickback gain unit for generating a p × 3 active power command correction signal in accordance with the overshoot amount detected in the 41 dead band element. That is, the N kickback circuit consisting of 41 and 42 corrects the effective power when N tries to deviate from the variable speed band (to prevent further runaway of N. PΣ in FIG. 1). As is clear from FIG.
, P × 2 and a composite signal of the above-mentioned active power correction signal p × 3. Reference numeral 16 denotes a power detector for detecting an actual drive output p of the generator / motor 1. 15 is an adder where the deviation ε between PΣ and P
_p is required. APR (output control device) 17 provides a direct-axis current command I _q with respect to the excitation current control device 37 in accordance with this power deviation epsilon _p. To the exciting current control device 37 is a fourth view of a known example similar horizontal axis current command I _d and the direct-axis current command I _q, the actual three-phase exciting windings of the rotor and enter the slips phase angle theta _S described above Determine the voltage command. V ₀ is the set value of the voltage of the generator / motor, 33 is the reactive power controller AQR, and the voltage set value V ₀ is corrected by this output ΔV ₀ . VΣ is a composite signal of V ₀ and ΔV ₀ , V is the actual voltage of the generator / motor, and 35 is an adder for calculating the deviation ε _v between VΣ and V. The AVR 36 calculates the horizontal axis current I _d according to the voltage deviation ε _v
It is a voltage control device which determines. In the above, PΣ → 15 →
The control loop of ε _p → APR → I _q → 37 → 3 → 1 → 16 → P → 15 can be called an active power control system. The stability and speed of the active power system are appropriately set by the gain of the integral element and the proportional element in the APR (output control device) 17. On the other hand, the control loop of VΣ → 35 → ε _v → 36 → I _d → 37 → 3 → 1 → voltage detector not shown → V → 35 is a voltage control system, and the stability and responsiveness of this voltage control system is AVR36. It is set appropriately by the integral element and the proportional element gain in the (voltage controller). The control loop of N ₀ → 30 → ε _Nb → 31 → p × 1 → 27 → active power control system described above → 6 → N → 30 is a speed control system. The responsiveness and stability of the speed control system are set to desired levels by adjusting the gains of the proportional element 31a and the integral element 31b in the speed control unit 31. By the way, in the present invention, the point is to allow a temporary following fluctuation of the active power p when the fluctuation of the power system frequency f is large during the idling operation. Therefore, it is necessary to take care not to make the gain of the proportional element 31a or the integral element 31b in the speed control unit 31 excessive. That is, if the response speed of the speed control system is excessively increased, even if p × 2 occurs temporarily, it acts to make it disappear quickly by the inverse fluctuation of p × 1. By the way, as a result of suppressing the response speed of the speed control system, temporary fluctuation of the rotation speed N is inevitable. However, since it is a variable speed machine as described above, normal operation can be continued as long as N is within the variable speed band. However, when N tries to jump out of the variable speed band, the variable speed band should be given priority over the above-mentioned f response function, and this is achieved by the above-described N kickback circuit. The gain also needs to be quite high. The present invention can be easily applied to a variable speed system in which a power converter is provided on the primary side of a generator / motor. Hereinafter, the normal operation can be continued with reference to FIG. FIG. 5 is an explanatory diagram of the operation of the variable speed hydraulic machine of the present invention and the electric power system to which it is connected. .DELTA.k _W of (a) shows a sudden demand imbalance power generated electric power system, the sum of the supply power is the same in this case such as to the power system load with elsewhere on the same power system is cut off This means that the total load of the power system has increased. As a result, the frequency f of the power system rises as shown in (b). As a result, the frequency f of the power system rises as shown in (b). Then, the f-response function of the hydraulic machine of the present invention connected to the power system operates, and the active power command p × 2 changes as shown in (c). On the other hand, each power plant connected to the same power system by the action of the AFC (self power frequency control device) or the like should reduce its output in accordance with the fluctuation of f. The sum of the decrease in the power supply at each of these power plants is the solid line in (d). Active power command p × 2
The actual drive output (motoring) p of the generator / motor of the variable speed hydraulic machine fluctuates in accordance with the fluctuation of As a result, the rotational speed N of the hydraulic machine is accelerated as shown in (f), and upon detection of this, the above-described speed control system responds, and the active power command p × 1 responds as shown in (e) to decrease the rotational speed N. I do. However, since the response speed of the speed control system is relatively low as described above, p
Immediately after this disturbance, the sum of × 2 and p × 1 is almost dominated by p × 2, and the response is almost (c). However subsequent sum of p × 2 reaches the time t _b is has decreased naturally by the action of the time constant T ₁ p × 2 and p × 1 is inverted from positive to negative, thereby rotating speed N is (the) And returns to the target rotation speed N ₀ as shown in FIG. By the way, the active power control response (p
× 2−p × 1), the sum ΔK _WX of the power supply and demand imbalance eliminating action of the same power system is the sum with the solid line in (d), and eventually becomes like the dotted line in (d). That is, the effect of the present invention resides in that the solid line in (d) is changed to a dotted line, that is, the power supply / demand imbalance is quickly eliminated to suppress the fluctuation of the power system frequency f. Of course, the effect of the present invention is limited to a short time immediately after the occurrence of the disturbance, as shown in the figure, and the system normally waits for the response of the original power source (various power plants, etc.). However, the response of the original power source cannot generally be easily made fast due to the restriction of each plant. Taking this into account, the role played by the present invention is by no means small. In other words, by having the hydraulic machine of the present invention, the active power response speed of the power system is improved and the fluctuation range of the power system frequency is reduced.
Also, it has the ability to follow a relatively fast, short-period power supply and demand imbalance that occurs in the power system. Conventionally, idling mode is used for power generation and pumping mode by opening the guide vane as soon as a command is given, or phase adjustment operation (rotation direction is both turbine direction and pump direction) for the purpose of improving the power factor of the power system. Although it has been adopted for the transitional waiting operation, the present invention enables these operations to be performed as usual while simultaneously exhibiting new functions. [Effects of the Invention] According to the variable speed hydraulic machine of the present invention, active power can be rapidly absorbed or released from the power system according to the frequency fluctuation of the power system, so that the active power adjustment capability of the variable speed hydraulic machine can be improved. It is possible to efficiently use the power supply / demand balance of the grid, and to increase the power supply / demand balance capability of the connected power grid.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing details of a 31 speed control unit (of FIG. 1). FIG. 3 is a diagram showing an alternative circuit from Δf to p × 2 in FIG. 1, and FIG. 4 is an explanatory diagram of a conventional biaxial exciting current control. FIG. 5 is an explanatory diagram of the operation of the hydraulic machine of the present invention and the electric power system to which it is connected. 17 ... APR, 33 ... AQR, 36 ... AVR.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-99677 (JP, A) Japan Institute of Invention and Innovation Technical Publication No. 85-14664 (58) Fields investigated (Int. Cl. ⁶ , DB name ) F03B 15/04 F03B 15/08

Claims (1)

(57) [Claims] A hydraulic machine, a generator or a motor directly connected to the hydraulic machine, a power converter provided on a primary side or a secondary side of the generator / motor, and an electric power connected to a primary side of the generator / motor Detecting means for detecting fluctuations in the frequency of the system, in a variable-speed hydraulic machine that performs variable-speed operation, in the idle running mode in which the water surface of the runner chamber is depressed and the runner runs idle, the detection is performed by the detecting means. When the frequency of the power system is increased, the rotation speed of the hydraulic machine is increased, and when the frequency of the power system is decreased, a control unit is configured to decrease the rotation speed of the hydraulic machine. Variable speed hydraulic power machine. 2. 2. The variable speed hydraulic machine according to claim 1, wherein a vertical axis of an exciting current of the rotor of the generator / motor is controlled by an active power control signal, and a horizontal axis of the exciting current is controlled by a reactive power signal. machine. 3. The variable speed hydraulic machine according to claim 1 or 2, wherein a speed command means for giving a rotation speed command value of the generator motor;
Speed detection means for detecting an actual rotation speed of the generator motor, wherein the control device controls the power converter so that a deviation between the rotation speed command value and the actual rotation speed is minimized. And variable speed hydraulic machine.