JPS59181925A - System frequency and voltage stabilizing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

[Field of the Invention] The present invention relates to a method for stabilizing the frequency and correction of a system to which loads with varying active and reactive power are connected and which are fed by a prime mover/generator unit having predetermined static characteristics. It is related to ζ2. [Prior art and its problems] The middle part of Figure 1 (2 shows the system 1 feeding the resistive load 2 and the inductive load 3 (2). Various power generation devices whose generated power fluctuates greatly depending on environmental conditions, such as wind power generators4
, a solar battery generator 5, a solar energy generator or a thermal generator 6 driven by thermal energy ('l-). What they have in common is that they depend on environmental conditions and are almost independent of the size of the loads connected to the grid.However, for the generation of active power,
It also involves the transfer of reactive power, which varies according to environmental conditions. Generator 4. 5. 6 is not in a condition to meet the active power demand of the load, an additional controllable prime mover/generator unit 7 is provided. The prime mover of this unit 7 can be, for example, a diesel engine 8 whose speed is controlled according to the speed-to-power characteristic n/P. This diesel engine 8 is connected to the system 1 via a generator 9. By the control device 10 of the generator 9

), the reactive power Q can be supplied to the grid 1 or absorbed from the grid 1 within a certain limit range. In that case, the output voltage U of the unit 7 varies according to the u/Q characteristic of the generator 9. In such a device, the diesel engine 8 has to be turned on due to the reactive power demand even though the power generated by the generators 4, 5゜6 is almost in balance with the active power demand of the system @1. There are often cases where λt is required. In that case, although the diesel engine 8 is almost under no load,
The engine 8 and the generator 9 are operated at high speeds outside the range where the combustion process of the diesel engine 8 is optimally operated and the engine 8 and the generator 9 are highly efficient. Furthermore, it is often difficult to maintain the frequency and voltage of system 1 at their rated values within the desired tolerance limits. Figure 2 shows the rotational speed n or prime mover of the diesel engine 8! /The output frequency f of the generator unit 7 is the active power P
It is shown as i-it. In addition, there are two units in Figure C.
, f Nenn Nenn1 PNenn are fL rotation speed and frequency, respectively. It represents the rated value of active power. The active power is given in advance by the demand of the grid. However, the speed, or frequency, can vary slightly within narrower limits than the engine's drive control. Generally speaking, the speed vs. set, !t.same characteristic (= set, !t
It is often the case that a plurality of prime mover/generator units are operated in parallel, and the active power is divided equally between each unit. The relationship between the output voltage U and the supplied (positive) reactive power or absorbed (negative) reactive power Q of the unit 7 is usually set as a straight line "static characteristic" as shown in Figure 3. In the figure, uN8nn is the rated value of the output voltage. When designing a unit, it is generally assumed that the unit generates the rated frequency fNenn of the grid at the rated speed nNeI□11, and the reactive power Q-
0, the rated power of the grid is 1fuNenn (harmonized into one system. The optimum conditions for unit operation can be obtained at those rated points. However, the active power transmission part of the grid or the The increase causes a decrease in rotational speed or system frequency and system voltage. [Object of the invention]
yq/' Source = I;・
To stabilize the '4 pressure and frequency of the system 1RIa under operating conditions that allow rotation (2A6゜ [Structure of the Invention]) This purpose is achieved by non-invention. The characteristics are set so that the prime mover/engine unit is operated at the optimum operating point when the system is at the rated voltage and frequency, and the system is equipped with a transmission section. The wind energy energy accumulator is connected via the transmission device, and from the control deviation between the system frequency and the rated frequency of the system, the target value for the active power transmission part is formed, and the system g4f voltage and the system g4f voltage are connected. This is achieved by forming the target value of the reactive power transfer 141 from the control deviation between the rated pressure of the system and the rated pressure of the system. The present invention will be explained in more detail.The present invention will be explained in more detail.
The static characteristics of the unit 7 are given in advance by the rated voltage of the system and the constant frequency C2 so that the unit is turned over at the optimum operating point. System 71. 1'C1 includes an electrical energy storage device 11, for example 11, and one or more storage batteries, which are controlled via an electrical energy transmission device, such as an inverter control 13, or one or more inverters 12. connected via. control of the A/L transmission system (northern 13 is active power supplied to the system via the three-way 6ft output terminal of the inverter 12 according to the target value PWR given by the input as fL);
In addition, the target value QWR given as a second reference input is
Accordingly, the reactive power can be marked separately/2 (two towns) (two towns).The control deviation f- of ml between the grid frequency f and the rated frequency f-f From f to A, active power transmission part 1 of the energy transmission device
1] is formed, i:r control deviation u between system voltage U and rated voltage u
-u to reactive power transmission section j-1: l C') Target value QW
R is formed. Therefore, in Fig. 1, the voltage 'f of system 1, that is, the system voltage U, is taken out by the voltage pressure detector 14, and then the system frequency f is detected by the frequency detector ]5. . This system frequency f is input as an actual value to the internal fluid flow regulator 16. Frequency adjuster 160) The desired value f is taken out from a setting device 17 consisting of a potentiometer depending on the rated frequency of the system. Similarly, from the system voltage U, the voltage amplitude detector rectifier 18
Accordingly, the actual value U of the system pressure amplitude is taken out from the setting device (potentiometer 19) and input into the amplitude regulator 20 along with the target value U corresponding to the rated pressure of the system. The frequency regulator 16 outputs the effective power target value P□, and the frequency regulator 20 outputs the active power target value QWR.The setting of the prime mover/generator unit 7 is performed. , this unit sets its rated output to the grid frequency (e.g. 6o
Hz). The active power demand of the grid is P N et
When z < (P N enn ) Ag- becomes smaller and the load on unit 7 becomes lighter, without the device of the present invention, the frequency imitation of unit 7 and ♀comb 1 rises to ]-,
With no load, the frequency reaches, for example, 105 C2 of the rated frequency. On the other hand, when the active power extracted from the unit 7 and input exceeds the rated power 2, the system frequency decreases as the active power increases. The frequency regulator 16 now outputs the active power setpoint value and serves in such a way that an active power PAg is supplied to the system 1 from the energy accumulator 11 via the innovator 12 and its control J3. In that case, the system = the clamping part wave number is equal to the rated frequency (target frequency f) and 2"
If L, the active power demand between the system 1 and the energy storage device 11 is zero. The direction of the 1llAj node of the regulator is such that when the system frequency increases (21. the active power is absorbed completely, and therefore the A/L private unit 11 is charged) and when the system frequency decreases (2. Revised to 1”L, soj
From ti2, the leggy accumulator 11 is discharged. Figure 4a shows the active power demand PN of system 1 in the form of a sine wave.
This shows the temporal variation of etz. Time t. Then, the active power demand Pr1tz is equal to the rated power (P) of the prime mover/generator unit 7, i.e. at time t.Then, as can be seen from the frequency/power diagram shown in Figure 4, the unit 7 or the factor number of system 1 is equal to the rated frequency ('-. 1 Yellow C 2 of the same diagram shows the output active power PwR of inverter 12 plotted 2t, which is the PWR of the point indicating the relevant time point. Active power demand of the system in diagram 3 of Figure 4a from the perpendicular line to which it belongs]] + qet
As z changes, this active power demand increases to special electric power tX, but this increase is covered by appropriate control of the output active power PWR of the inverter 12. As a result, Until time t, the systematic part? skin number] is the same value (
= is maintained, but the active power PWR is ignited for t. In that case, the inverter 12 will print a(l) up to its output limit.
Therefore, λt is the case where the transmission current reaches its maximum value ζ:i.For such a case, a distance between the measured current value and the current limit value is of $') i:
[+] ゛From the deviation, the inverter output voltage lK
When the seismic field value to which j-i is to be affected is formed, λt; 6°, between time points t1 and t3, if this current limiting action moves by 1, the inverter 12 increases its constant critical active power (PWR).
. can be transmitted. Therefore, the grid frequency decreases while the active power demand of the grid still increases (at time t2). The magnitude of the fluctuation is given by the static characteristics in Figure 1B2, and Figure 4 (2 is shown slightly overexposed to make it easier to understand the forward direction. At time t2, the active power demand P
etZ begins to decrease, and at time t3, it again decreases to the rated power of unit 7, that is, the inverter's limit power (2).
Therefore, the time t when the inverter 12 is operated at zero output
4, the rated frequency of the system is maintained again λ. 1 for the time t, ~t8 when the active power demand of the grid falls below the rated power of the unit 7. For example, if the inverter is controlled with negative polarity at 1t, the system frequency remains at the rated frequency only during the period from t7 to t7 (inverter current limit section). -1: In short, normal operation (time t.-1,,13~
t3. (operation between t7 and t8), the prime mover/generator unit is able to operate at the normal optimum operating point at t, and in this state, the prime mover/generator unit, other generators, and loads shown in Figure 7FJ1 (without affecting the control of the output active power of the inverter in connection with the current limit). Figure 5 a, b, and cj show the same behavior as Figure 4 a, b, and c regarding reactive power. There is a resistive load, the prime mover/generator unit does not generate any idle current according to its operating point, and the amplitude regulator 20) outputs no power target value QWR'. The grid voltage is at time 1. Maintained at rated value uNenn:I. This is because the increase in reactive power demand 'QNetz
i=r controlled accordingly! The magnitude of the reactive power output is limited by the commutation capability (2) of the inverter's power section. Due to current limit 1.
Only the maximum current can flow through the inverter. Therefore, during this current limitation, the system voltage follows the U/Q characteristic curve (2) shown in FIG.
At 3, the total stationary power demand of the grid is again covered via the inverter, and the grid voltage returns immediately to its rating. If the power demand of the grid continues, the capacity of the energy storage is effectively exhausted. It may happen that the output voltage of the energy storage unit reaches the absorption capacity of the energy accumulator when the single power output of the grid is sold as iai.In such a case, the output voltage Ud of the energy storage Voltage limit given in advance to the accumulator [Direct IJdmax
Alternatively, it is preferable to form a limit value for limiting the target value for effective compensation transmission (2) from the control deviation between the voltage lower limit value Udmin and the voltage lower limit value Udmin set for the energy accumulator in the 1st state. This case is illustrated in Figures 6a, b, c, where at time t, the exhaustion of the energy storage (
capacity decrease), the output power is PwR-o (time t2)
The value decreases to . Part 2, the energy demand of the late system 7 must be 4t due to the capacity increase from unit 7, and therefore the wave number of the system as a whole remains below the rated frequency until time t3. A similar behavior occurs at time t4, when the energy storage capacity is fully loaded and the energy storage is able to receive and take useful power from the grid, so that the grid frequency is lower than the rated frequency. From now on
1:= This occurs when i=1 increases. In summary, for the illustrated progression C2 of the power demand of the grid, the corresponding frequency/active power characteristic line or voltage/reactive power characteristic line C2 is at the time point 91 given in the diagrams of FIGS. Vomit and change. Deviations from the rated value only occur when the output limit of the energy storage and energy transfer devices is reached, but this means that these units should be designed to be even larger ( 2 can be avoided to a greater extent than 2. In devices of this kind, a certain voltage fluctuation is often tolerated to obtain 1. Therefore, certain tolerance limits can be given in advance for the reactive power transfer. The setpoint value for the power transmission shall be formed from the control deviation between the system tf, voltage and the tolerance limit below or above it when the system voltage decreases or increases; in this case also the time interval of FIG. 7. Between t3 and t8, certain fluctuations occur that are not taken into account there. Instead, we obtain a reference input for the active or reactive current.Then, from each setpoint value, the energy transmission device is divided by the previous measured value of the current (-therefore, the active current to be transmitted is also 1.< can form the necessary target values for the reactive current and the reactive current C2.
Anastomosis, current measurement, including rough adjustment control is essential. A preferred energy transmission device having a control unit is described in German Patent Application No. 3,236,071 (2) and is shown as device 30 in FIG.
I'm here. Almost the same symbols as those used in the specification of the L patent application are used here, and the explanation of the control device part (two parts will be omitted).・Control input terminals 31 and 3 for cos ψ and reactive current target value 1w/sin ψ
2 and is used as an energy storage device 11.
The active current and reactive current given by the target value are transferred from the storage battery 11 (battery voltage Ud) to the system 1 by 4JI.
Furthermore, in the device 30, the amplitude of the system voltage UN is also formed and can be extracted from it. Perfection 2
I'm here. This limiting circuit 33 controls the gradient current 1. Limit u to the maximum (direct). Rectifier 34
Rectify the measured value of the output current 'W' of Impark 12 with
Further, λt is smoothed by a smoothing circuit 35 to obtain the actual current value F. The apparatus shown in FIG. 7 is also provided with a frequency generator 15 which generates a corresponding system frequency f from the system voltage U. System: The sectional surface deviation f - f between the bowl wave number f and the system rated frequency given in advance from the frequency setter 17 as the target value f is determined by the frequency adjuster 16 (operated by two people. This frequency adjuster J6 A voltage limiting circuit 40 is provided on the output side (=). The voltage limiting circuit 1840 limits the output voltage of the frequency regulator 16 to the maximum value and 1 and lower values during the active power period as the value PWR. In this case, the upper limit 11α is supplied from the regulator 41. The regulator 41 has the output voltage [Jd of the energy accumulator 11 and the charging mist state ζ''' of the energy accumulator 11 - the corresponding upper limit The control deviation max difference Udmax-Ud between Ill@U and Ill@U is input.Similarly, the lower limit value of the voltage limiting circuit 40 is determined from the regulator 42 by controlling the output voltage of the energy accumulator 11. [It is formed from the control deviation Udm1n-Ud between Jd and the lower limit value Udn11n corresponding to the discharge state of the A/R energy accumulator 11. From the effective current target value formed by the Rani frequency vi regulator 16, A changeover switch 43 is provided to switch to the active power target value given from the outside.Such a changeover circuit is also provided for the reactive power target value (changeover switch 60). In this case, it is advantageous if the entire installation is operated by means of a computer which controls the various generators and generator units in a load-balancing manner. In order to form the current target value ■÷・cosψ (2), a divider circuit 44 is provided here.The absolute value U of the system voltage is input to the divisor input terminal of the divider circuit 44. The 2'L quotient PwR/u obtained here is smoothed via a smoothing circuit 45, and further passed through a limiting circuit 46 to the input 4 child 3.
I am guided by 1. The control circuit 46 is given in advance the current I flowing through the A/L transmission device (=limiting current I).
It is ax. Here again, the voltage limit value is the control deviation ■wmax-I
2 is taken out from the regulator 47 to which y+ is input. Input terminal 32 for reactive current target value IW・Slnψ
A limiting circuit 48 is also provided in front of the circuit. The limiting circuit 48 obtains its limiting value from the output 4 of the regulator 47. Depending on the case, the reactive current target value is calculated as 1/quotient Q via the smoothing circuit 49.
It is taken out from the output terminal of the division circuit 55 as R/u. In addition, the dividend input terminal of the division circuit 55!・The reactive power target value QWR is input. This reactive power target value is 2. As already mentioned with reference to FIG. 1, the target value U is formed from the difference between the system rated voltage set in the setting device 19 and the actually measured system voltage U. The amplitude H, S node 20 shown in FIG. 1 (Z is 2t) has hysteresis characteristics. 1t1 is obtained from the individual regulator 57 via the diode 56. The adjustment M6j unit 57 is configured to respond only when there is a difference in the control deviation. The forward target value is taken out from the second regulator 59 via a diode 58 inserted with the corresponding polarity. Voltage and permissible upper limit 11
Control deviation between U + ΔU (U + ΔU) − U
is input. [Effect of the invention] According to this Vtt, the load 2. connected to the system 1.
3 and a generator 4 provided in connection with these loads.
, 5.6 is the system, regardless of the invalid 'seca of string 1, the city,
This can be achieved by operating at the optimal operating point depending on the operating conditions at the time. Motion! The operating point of the generator unit 7 is always kept almost unchanged; the frequency and voltage of the grid also remain unchanged. Rather, system reactive 1 - drag and short-term active power excess or active power excess are energy energy accumulators 1.
1 and automatic control]. The output limit of the A.I. energy bond accumulator 11 and/or the inverter 12 is C2', which may cause fluctuations in the frequency, i-5 and voltage of the grid only when they are connected in duplicate.
I don't know.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a characteristic diagram showing the active power characteristics of the prime mover/generator unit, and Fig. 3 is the static characteristic of the reactive power of the same unit. Figure 4a is a diagram showing the active power demand of the grid and the output active power of the prime mover/generator unit, Figure 41
), C is the thread 5 and used according to the invention.
, Diagram showing the output active power ζ of two A/L energy accumulators and the one-dominance characteristic, Figure 5 a, b, c
is the same diagram as Figure 4 a 1 b + C regarding reactive power, and Figure 6 a, b, and c are Figure 4 a,
FIG. 7 is a block diagram showing an example of the detailed configuration of the apparatus of the present invention. 1...System, 2.3...Load, 4.5.6
... starter, 7... prime mover/engine unit, 8... diesel engine, 9... power generator,
DESCRIPTION OF SYMBOLS 11...Energy accumulator, 12...Inverter (ALGY transmission device), 13...Inverter control unit, ]5...Frequency detector, 16...
・Frequency adjuster, 18...voltage amplitude detector, 20・
...Amplitude adjuster.

Claims (1)

[Claims] l) Active power (P4,.t2) and reactive power (Q N
In a method for stabilizing the frequency and voltage of a system to which loads of varying demand (etZ) are connected and which are supplied from a prime mover/generator unit having predetermined static characteristics,
The static life of the prime mover/generator unit is set such that the prime mover/generator unit operates at its optimum operating point at the system's rated pressure and rated frequency, and the system's (2) , an electric energy storage device is connected via an energy transmission device having a separately controllable active power transmission section and a reactive power transmission section, and the system frequency (
f) and the rated frequency of the system (f)
f−f) to the target value (P,
R) and forming a target value (QWR) for the reactive power transmission unit from the control deviation (u − u) between the system voltage (u) and the rated voltage of the system. Frequency and voltage chemotaxis methods. 2. In the method according to claim 1, A.
The output voltage of the energy accumulator (Ud) and the three values above the voltage set for the energy accumulator in the full state of charge (U+)
and the voltage lower limit value (
A system frequency and voltage stabilization method characterized in that a limit value for limiting a target value of q of an active power transmission section is formed from each control deviation between U"dmin). 3) Patent Claim In the method described in Section 1 or Section 2, the target value (QWR) of the reactive power transmission section when the grid voltage (u) decreases or increases is set to the allowable lower limit (U -
A method for stabilizing the frequency and voltage of a grid, characterized in that it is formed from the control deviation between the system voltage (u) and the permissible upper limit value (U + ΔU ). 4) In the method according to any one of claims 1 to 3, the method is effective as an energy transmission device.
Using a power converter having a current and reactive current regulator, the target values of active and reactive currents are formed by dividing the target values of active and reactive power by the measured value of the current flowing through the power converter. A system frequency and voltage stabilization method characterized by: 5) The method according to claim 4, characterized in that the upper limit value of the current target value is formed from the control deviation between the measured value of the current flowing through the power conversion device and a predetermined current limit value. Frequency and voltage stabilization method for f1-order system.