JPH0348730B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] This invention automatically determines the initial values (generator output value, transformer tap value, phase adjustment capacity of phase adjustment equipment) of the power system used by a computer applied to a power supply simulator, etc. The present invention relates to an automatic initial state setting method for a power system to be set.

[Conventional technology]

Figure 1 is a flowchart showing the conventional initial state setting method for a power system, and Figure 4 is a system diagram to which the conventional power system initial state setting method is applied. In the figure, 1 is a generator, 2 is a transformer. 3 is transformer 2
4 is a phase modifier, 4a is a stator controller SC of the phase modifier 4, 4b is a shunt reactor shr of the phase modifier 4, and 5 is a load bus. Next, the operation will be explained according to the flowchart shown in FIG. First, in step ST1, the generator of the generator 1 is adjusted in consideration of the sum of the loads P _L , Q _L (P _L1 +P _L2 , Q _L1 +Q _L2 ) of each load bus 5 and the loss in each load bus 5, etc. The operator sets the output PG1. Next, in step ST2, the operator sets the tap value of the tap 3 in the transformer 2 and the phase modulating capacity of the phase modulating equipment 4 based on past experience. Next, in step ST3, the voltage value V (V ₁ , V ₂ ) and the reactive power value Q (Q ₁ , Q ₂ ) at each load bus 5 are calculated by executing power flow calculation.
seek. Next, in step ST4, step ST3
The voltage value V, reactive power value Q, and reference voltage value found in
V ₀ (V ₀₁ , V ₀₂ ), reference reactive power value Q ₀ (Q ₀₁ , Q ₀₂ )
It is determined whether the difference between the
If it is not within the predetermined value (NO), proceed to step ST5. Next, in step ST5, the operator partially corrects the tap value of tap 3 in transformer 2, the phase modulating capacity of phase modulating equipment 4, and the generator output PG1 of generator 1, and returns to step ST3. As mentioned above, the above operation ends a series of processes when the voltage value V and the reactive power value Q become within predetermined values, and at that point, the voltage of the power system used for power supply simulation is This means that the initial value of reactive power is obtained.

[Problem to be solved by the invention]

Since the conventional initial state setting method for the electric power system is configured as described above, there is a problem that the setting requires much time due to the intervention of the operator. This invention was made in order to solve the above-mentioned problems, and provides a method for automatically setting the initial state of a power system that can quickly obtain the initial state by automatically setting the initial state of the power system. The purpose is to obtain.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a flowchart showing a method for automatically setting the initial state of a power system according to an embodiment of the present invention;
FIG. 5 is a system diagram to which an automatic initial state setting method for a power system according to an embodiment of the present invention is applied. In the diagram, the same reference numerals as those in the conventional system indicate the same or corresponding parts, and the explanation thereof will be omitted. 6 is a VQ device that controls the phase modulating capacity of the phase modulating equipment 4. Next, the operation will be explained according to the flowchart shown in FIG. First, in step ST7, the sum P _L (total load amount) of the loads on each load bus 5 is set. Note that only step ST7 is a manual process. Next, in step ST8, a constant ratio of the total load P _L is estimated as the loss P' _LOSS (for example, assuming the constant ratio is 5%, P' _LOSS = P _L ×0.05 is estimated). In addition,
If you come from step ST11 to step ST8,
The process of estimating this P' _LOSS is omitted, and the sum of the loss P' _LOSS and the total load P _L is set as the required power generation power, and the generator output PG1 of generator 1 (P _G1 = P _L
+P′ _LOSS ) is determined. Next, in step ST9, the tap value of tap 3 in transformer 2 is set to an intermediate tap value (the tap is at the center position), and the phase modulating capacity of phase modulating equipment 4 is set to zero. Next, in step ST3, the voltage value V (V ₁ ,
V ₂ ), reactive power value Q (Q ₁ , Q ₂ ) and each load bus 5
Find the total loss P _LOSS . Next, in step ST10, the difference between the loss P _LOSS obtained in step ST3 and the initial estimated value P′ _LOSS is within a predetermined value, for example, within 1% (|P _LOSS − P′ _LOSS /P _LOSS |≦0.01). It is determined whether or not the loss is within a predetermined value, and if it is not within a predetermined value, it is determined that the loss P _LOSS is unbalanced and the process proceeds to step ST11. On the other hand, if it is within the specified value,
Voltage value V, reactive power value Q, reference voltage value V ₀ (V ₀₁ , V ₀₂ ), reference reactive power value Q ₀ obtained in step ST3
_{It is} determined whether the difference from Determine that it is balanced and proceed to step ST12. Here, in step ST11, the loss P' _LOSS is corrected to eliminate the loss P _LOSS imbalance.
In other words, if the loss P _LOSS ≦P' _LOSS , increase the fixed ratio (for example, from 5% to 8%), and P _LOSS <
If P′ _LOSS , reduce a certain ratio (for example, 5% from the previous time)
3%), P′ _LOSS based on that constant ratio
Determine (P′ _LOSS = P _L × constant ratio) and proceed to step ST8.
Return to On the other hand, in step ST12, the tap value of the tap 3 in the transformer 2 and the phase modulating capacity in the phase modulating equipment 4 are corrected in order to eliminate the voltage V and reactive power Q imbalance. The details of the modification are shown in FIG. 3. Then, in step ST13, the same power flow calculation as in step ST3 is executed, and the
Return to ST10. By repeating the above operations, the initial state of the power system can be automatically set. FIG. 3 is a flowchart showing details of step ST12 in FIG. 2. First, at step ST15,
Set the initial value of counter N that sets the integration time. Next, in step ST16, the integration time Δt is reduced to Δt ₀
Find from ×N. Here, Δt ₀ is the integral step width of the actual VQ device. Next, in step ST17,
Calculate the deviation between the voltage V and reactive power value Q found in step ST3 or ST13 and the reference voltage value V ₀ and reference reactive power value Q ₀ (ΔV=|V−V ₀ |, ΔQ=|Q−Q ₀ In addition, the dead band of the deviation ΔV, ΔQ and the voltage of the VQ device 6 (region in which the VQ device 6 does not operate because the amount of deviation of ΔV is smaller than a predetermined value) constant K ₁ V, VQ
The deviation of the reactive power of the device 6 from the dead zone constant K ₂ Q (Δv=ΔV−K ₁ V, Δg=ΔQ−K ₂ Q) is determined. Next, in step ST18, the time integral value Δv×Δt of the voltage deviation Δv is compared with the set value εTV of the VQ device 6, that is, εTV≧Δv×Δt, and it is determined that the set value of the VQ device 6 is higher. If it is large, go to step ST19, if it is small, go to step ST20.
go to Next, in step ST19, the set value εTQ is determined as εTQ≧Δq×Δt. If the set value εTQ is larger, the process goes to step ST21, and if it is smaller, the process goes to step ST20. In step ST20, when ΔV, ΔQ>0, the tap value of tap 3 of transformer 2 is lowered, and ΔV>
0, when ΔQ<0, open the stacon Cs4a,
Also, turn on the shunt reactor ShR4b, and when ΔV<0, ΔQ>0, turn on the star converter Cs4a.
, and open shunt reactor ShR4b, and when ΔV, ΔQ<0, increase the tap value of tap 3 of transformer 2. Next, in step ST21
It is determined whether step ST20 has been performed for one or more VQ devices 6 during the repetition for the number of VQ devices 6. If YES, the process in FIG. 3 is terminated; if NO, Go to step ST22.
Next, in step ST22, N=N+1 is performed in order to advance the time by one step. This logic is based on the type of deviation (voltage or invalid It changes depending on the power consumption).

【Effect of the invention】

As described above, according to the present invention, the voltage value and reactive power value of each load bus are calculated by power flow calculation, and the voltage value and the predetermined reference voltage value, the reactive power value, and the predetermined reference reactive power value are calculated. The system is configured so that the tap value of the transformer and the phase adjustment equipment are adjusted based on the largest deviation for each of the above-mentioned load buses, so that the power can be adjusted automatically and quickly. This method has the advantage of being able to obtain the tap value of the transformer and the phase adjustment capacity of the phase adjustment equipment for each load bus in the system.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing a conventional method for setting the initial state of a power system, FIG. 2 is a flowchart showing a method for automatically setting the initial state of a power system according to an embodiment of the present invention, and FIG. step
A flowchart showing the details of ST12, FIG. 4 is a system diagram to which the conventional power system initial state setting method is applied, and FIG. 5 is a system diagram to which the power system initial state automatic setting method according to an embodiment of the present invention is applied. Figure, 6th
The figure is a graph showing the dead zone of the VQ device. 1 is a generator, 2 is a transformer, 3 is a tap, 4 is a phase adjustment equipment, 5 is a load bus, and 6 is a VQ device. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] 1. Estimate a certain proportion of the total load of each load bus in a preset power system as a loss, set the sum of the load and the loss as the output value of the generator, and calculate each of them by power flow calculation. The power value of the load bus, the reactive power value, and the sum total of the loss of each load bus are determined, and it is determined whether the difference between the loss determined by the power flow calculation and the estimated loss is within a predetermined value. If the difference is not within a predetermined value, increase or decrease the fixed ratio according to the difference, estimate the loss again, determine the generator output value, calculate the power flow, and make the judgment again. It is determined whether the difference between the voltage value and reactive power value obtained by the power flow calculation and the reference voltage value and reference reactive power value at each bus line is within a predetermined value. Starting from the load bus line with the largest deviation, change the tap value of the transformer and the phase adjustment capacity of the phase adjustment equipment based on the deviation and perform the power flow calculation and judgment again.
A method for setting the initial state of an electric power system to obtain the output value of the generator, the tap value of the transformer, and the phase adjustment capacity of the phase adjustment equipment.