JPH0355843B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention performs reactive power control in voltage and reactive power control aimed at maintaining proper voltage in a power system and reducing power transmission loss using target values set according to changes in load. The present invention relates to a reactive power control device.

Reactive power control in primary substations generally involves on-load tap-changing transformers, power capacitors,
It is equipped with phase adjustment equipment such as a shunt reactor and a control device, and the control target value is set based on load prediction made in advance, and the tap switching of the tap-changing transformer at the time of load is controlled by the voltage regulating relay. in,
Additionally, the opening and closing of the phase adjustment equipment was controlled individually using a 24-hour timer.

However, since this control is based on a so-called time schedule, if the load curve varies depending on the day of the week or changes rapidly depending on the time of the day, the load curve may not match the expected load curve. Due to the difference, we are unable to follow suit,
There is a problem in that it becomes impossible to maintain an appropriate voltage as well as to perform optimal control of reactive power.

In order to improve this, it is possible to set the target value in detail based on a pre-assumed load curve, but since this is only a setting based on predictions, it is difficult to make it follow the actual load situation, and it is also possible to There is also the problem that setting a large number of settings increases the time and effort required for setting and is troublesome.

On the other hand, for reactive power control in voltage and reactive power control, voltage-priority control is adopted from the perspective of stable power supply to consumers, and optimal control is performed while maintaining the bus voltage within the dead band of voltage control. It is said that

However, since reactive power is controlled by operating the power capacitor and shunt reactor by turning on and off the circuit breaker, the change due to one operation is gradual. Therefore, there is a problem in that the dead band of voltage control may be exceeded due to the operation, leading to an increase in the frequency of operation. This increase in operation frequency is due to the wear and tear of the contacts, and the number of times the circuit breaker is used is estimated to be 8,000 to 10,000 times.
This causes the problem of shortening the life of the disconnector.
Particularly during periods of severe load fluctuation, reactive power increases in one direction (lag side or lead side), so if the amount of change due to one operation is small, the operation frequency of the breaker is increased, and the breaker is operated more frequently. This has the problem of shortening the life of the device.

In addition, concentrating operations on a specific shingle breaker during control will further shorten the lifespan of that shingle breaker, requiring early replacement, and hindering optimal reactive power control. It also has the problem of causing

The present invention has been made in view of the above points, and an object thereof is to provide a reactive power control device that controls reactive power using a target value calculated and set according to load changes. be.

Embodiments of the present invention will be described below with reference to the drawings.
In Figure 1, T ₁ , T ₂ , T ₃ , and T ₄ are multiple on-load tap-change transformers (hereinafter referred to as
(abbreviated as LRT), the primary side is connected to the line that transmits power from the upper system (e.g. 154KV), and the secondary side is equipped with current transformers CT ₁ , CT ₂ , CT ₃ , and CT ₄ respectively. Bank secondary busbar (hereinafter referred to simply as busbar)
It is connected to the bus BUS and transmits power at, for example, 154KV/77KV to the load L connected to the bus BUS. In addition, LRTT ₁ , T ₂ , T ₃ , and T ₄ are equipped with a tap switching control panel (not shown) for automatic voltage adjustment, and the tap switching control panel performs tap switching operation to control the bus line BUS. The voltage _VB can be adjusted. SC ₁ , SC ₂ …SC _o
are a plurality of power capacitors (hereinafter simply referred to as capacitors), ShR ₁ , ShR ₂ connected to the above bus line BUS via disconnectors CB ₁₁ , CB ₁₂ ...CB _1o , respectively.
...ShR _n is the bus disconnector CB ₂₁ , CB ₂₂ on the above bus line BUS
...Multiple shunt reactors (hereinafter simply referred to as reactors) each connected via CB _2n , CT _B
PT is a bank current transformer connected to the above current transformers CT ₁ , CT ₂ , CT ₃ , CT ₄ to derive the bank total current I _B , and PT is connected to the above bus BUS to derive the bus voltage V _B This is a voltage transformer designed to derive .

Next, a tap switching command is sent to the tap switching control panels (not shown) for LRTT ₁ , T ₂ , T ₃ , and T ₄ , and a
A description will now be given of the control device A that sends the closing and closing commands to CB ₁₁ , CB ₁₂ ...CB _1o and CB ₂₁ , CB ₂₂ ...CB _2n . 1 is a current converter connected to current transformer CT _B , which converts the bank total current I _B into voltage, converts it to direct current, and outputs it through a filter with a fixed time constant (for example, 2 seconds). ing. 2 is a reactive power converter connected to a voltage transformer PT and a current transformer CT _B , which calculates reactive power by inputting the bank total current for two phases and the bus voltage for three phases, and converts this into DC. The signal is output through a filter having a certain time constant (for example, 2 seconds). 3 is a voltage converter connected to the voltage transformer PT, which converts the effective value derived from the bus voltage V _B via an isolation transformer into DC, adds up the three phases, and converts it to a fixed time constant (for example, 0.3 seconds). It is designed to output through a filter with . The outputs of the current converter 1, reactive power converter 2, and power converter 3 are output as digital outputs via an analog-to-digital converter 5 having a multiplexer to a calculation processing unit (hereinafter abbreviated as CPU).
It is now sent out on the 6th. 7 and 8 are
A storage unit connected to CPU 6, storage unit 7 (hereinafter referred to as
PROM7) stores processing programs for power and reactive power control.
It is now executed by CPU6,
The storage unit 8 (hereinafter abbreviated as RAM8) has a PROM
Data for executing a processing program stored in CPU 7 is stored, and this data is read out in accordance with the program to cause the CPU 6 to perform arithmetic processing. 9 is an input/output unit connected to the CPU 6, and control conditions (for example, LRTT ₁ , T ₂ , T ₃ ,
T ₄ tap position, capacitors SC ₁ , SC _{2 .} . . SCn and reactors ShR ₁ , _{ShR 2 .}
Tap switching of LRTT ₁ , T ₂ , T ₃ , T ₄ , capacitors SC ₁ , SC ₂ ...SCn and reactors ShR ₁ , ShR ₂ ...
It is designed to make ShR _n input and trip. Then, the CPU 6 uses the bank total current I _B read from the current converter 1 via the analog-to-digital converter 5 to set a target value for voltage control.
Vref and target value Qref for reactive power control are calculated and set respectively, and based on these target values Vref and Qref, input from the voltage converter 3 and reactive power converter 2 via the analog-to-digital converter 5. The input/output unit 9 compares and judges signals (bus voltage V _B and reactive power Q and outputs commands for voltage and reactive power control).
It is now being sent out via .

Next, the target value Qref for reactive power control will be explained. This target value Qref is Qclk=Q _NIT −X・I _B ² ...(1) Qref=Qclk+Qsft ...(2) However, I _B : Bank total current (KA) Q _NIT : Invalid when bank total current I _B is zero Power ( ^MVar ) Qclk in equation (1) above is the reactive power Q _NIT when the bank total current I _B is zero (for example, 20MVar)
and _the reactance compensation X _{( e.g.} 50MVar ^/ KV ₂ )
are stored in RAM 8 in advance, and calculated using these Q _NIT , X and the bank total current I _B read through the current converter 1. or
In order to change the bank secondary reactive power target when the voltage of the upper system tends to rise excessively on special days such as Obon holidays and New Year holidays, the target reactive power is shifted in advance to multiple stages by remote or direct manual operation. The shift amount Qsft set as (for example, 1%)
(±2% as 20MVar), the target value Qref is set by calculating according to the above equation (2). This target value Qref is determined by the PROM7 program every very short period of time (for example, every 0.5 seconds).
The calculation settings are made by the CPU 6. In the calculation settings for the target value Qref above, if the shift amount Qsft is 0%, the target value Qref is
Qref=Qclk. Control of reactive power based on this target value Qref is performed by dividing the time period in which the load L rapidly increases and the time period in which the load L rapidly decreases. Since it increases on the delay side, the operating value Qop is increased by the target value Qref.
Qop=Qref+Qs/2...(3) However, Qs: Calculated and set using the unit capacitance (MVA) of the capacitor or reactor in the next operation, and read through this operating value Qop and reactive power converter 2. The reactive power Q is compared and determined, and if Qop<Q, the CPU 6 causes the input/output unit 9 to trip the reactor or turn on the tripped capacitor to adjust the reactive power. It's summery. In addition, since the reactive power Q increases on the leading side during the period when the load L suddenly decreases, the operating value Qop is calculated and set by Qop = Qref - Qs / 2 ... (4), and this operation According to the value Qop, if Qop>Q as described above, the input/output section 9 is output by the CPU 6.
The reactive power is adjusted by tripping the capacitor that has been turned on via the capacitor or turning on the tripped reactor. And the reactor
ShR ₁ , ShR ₂ ...ShR _n and capacitors SC ₁ , SC ₂ ...
The operation of turning on and tripping the SC _o is limited to one operation depending on the time period when the load L increases rapidly and the time period when the load L decreases rapidly, and is performed in rotation.

Here, the setting of the above operation value Qop will be further explained. Note that the description will be made regarding a time period in which the load increases rapidly, and assumes that the load increases rapidly.

When the operating value Qop is set as Qop = Qref + 2Qs/3 Depending on the system status, the reactive power Q read by the control device A via the reactive power converter 2 may change to point A as shown in Figure 2 A. ₁ , the reactive power Q is within the range of Qref<Q<Qop, so reactive power is not controlled, but since it exceeds the dead zone -δ for the power control target value Vref, the control device A A step-up tap switching command is sent from , a tap switching operation is performed, and point A ₁
The voltage is regulated from point _A2 . As a result, point A ₂
exceeds the operating value Qop (Qop<Q), so the reactive power is subsequently controlled by, for example, introducing a power capacitor, and from point A ₂ to point A ₃
The reactive power Q is adjusted accordingly. That is, A ₁ →A ₂ ,
The operation A ₂ →A ₃ is required twice, increasing the number of operations, and setting the operation value Qop to Qref+2Qs/3 leads to an increase in the operation frequency.

When the operating value Qop is set as Qop = Qref + Qs / 3 Depending on the system status, the reactive power Q read from the control device A may change to a point as shown in Figure 2 B.
If B ₁ is reached, it exceeds the operating value Qop (Qop < Q), so, for example, a power capacitor is input to control the reactive power, and as a result, the reactive power Q increases from point B ₁ to point B. Adjusted to ₂ .
However, as a result of this adjustment, point _B2 will exceed the dead zone +δ for the voltage control target value Vref, so a step-down tap switching operation is performed.
The voltage will be adjusted from point B ₂ to point B ₃ .
That is, as above, in this case as well, B ₁ →B ₂ , B ₂ →B ₃
2 operations are required, increasing the number of operations,
Setting the operating value Qop as Qop=Qref+Qs/3 increases the operating frequency as described above.

When the operating value Qop is set as Qop=Qref+Qs/2, the reactive power Q read from the control device A is
As shown in the figure, if point A is reached, it is within the dead zone of voltage control and exceeds the operating value Qop (Qop<Q), so for example, a power capacitor is turned on to control reactive power. As a result, the reactive power Q is adjusted from point A to point B while maintaining the voltage within the dead zone (Vref±δ). In other words, the operation from A to B only needs to be done once.

Furthermore, the reactive power Q adjusted to point B is larger than Qop' and smaller than Qref (Qop'<Q<Qref) position. (Incidentally, even if the power Q is ineffectively controlled by the unit capacity Qs of the next operation without voltage change, it will be adjusted from A to C and will not be controlled beyond the above Qop') . This means that it is possible to control the reactive power Q, which increases on the lagging side during times when the load increases rapidly, to the leading side as much as possible while maintaining the voltage within the voltage control dead band (Vref±δ). However, as a result, the number of operations of the shredder breaker can be reduced.

In other words, within the detection level as a dead zone, reduce the number of operations, including the number of voltage control operations, to advance as much as possible when the load increases rapidly, and to delay as much as possible when the load increases rapidly. It will be possible to control the reactive power on the side.

Reference numeral 10 denotes a power capacitor control circuit provided in the input/output section 9 in correspondence with the capacitors SC ₁ , SC _{2 .} . . SC _o . This is as shown in Figure 4.
The normally open contacts SC of the relays SC _1C and SC _1T are energized by the closing operation to the "auto" side of the changeover switch 43A provided on the control panel (not shown) of the capacitor for the control power supply, through the normally open contact 43ASCa of the relay 43ASC. _1Ca , SC _1Ta are connected in parallel, and the other end of this normally open contact SC _1Ca is connected with a breaker, for example CB _11.
The closing coil (not shown) and the normally open contact
A sheath breaker, for example, a trip coil (not shown) of CB ₁₁ is connected to the other end of SC _1Ta to form a drive section 10b, and the relays SC _1C and SC _1T are connected to the control power source.
The main control unit 10a is formed by connecting one of them to be energized by the output of the CPU 6, and by energizing the relay SC _1C , the
CB ₁₁ is turned on, and by energizing the relay SC _1T , the circuit breaker, for example CB ₁₁ , is finally disconnected. 11 is reactor ShR ₁ ,
ShR ₂ . . . A shunt reactor control circuit provided in the input/output section 9 in correspondence with ShR _n . This is the fifth
As shown in the figure, the control power is supplied to the reactor via the normally open contact 43AShRa of the relay 43AShR, which is energized by the closing operation to the "auto" side of the changeover switch 43A provided on the operation panel (not shown) of the reactor.
Relay ShR _1C , normally open contact of ShR _1T ShR _1Ca ,
Connect one end of ShR _1Ta in parallel and this normally open contact
The drive unit 11b is formed by connecting a closing coil (not shown) of a sheath breaker, e.g. CB ₂₁ , to the other end of _{ShR 1Ca ,} and a trip coil (not shown) of a shear breaker, e.g. CB ₂₁ , to the other end of ShR 1Ta.
ShR _1C and ShR _1T are connected to a control power source so that one of them is excited by the output of the CPU 6 to form a main control section 11a, and by the excitation of the relay ShR _1C , a circuit breaker such as CB ₂₁ is activated. let them put it in,
Furthermore, the excitation of the relay ShR _1T causes the breaker, for example CB ₂₁ , to become energized.

The input/output section 9 includes a tap switching control (not shown) that sends a tap switching command to the tap switching devices (not shown) of LRT ₁ to _{T 4} , as well as the power capacitor control circuit 10 and the shunt reactor control circuit 11. A circuit is provided.

Next, its operation will be explained. First, CPU6
The bus voltage read through the voltage converter 3 by
V _B is set to the voltage control target value Vref by tap switching of LRT ₁ to T ₄ and turning on/off of capacitors SC ₁ ...SC ₄ and reactors ShR ₁ ...ShR _n .
Adjust to within the dead zone δ (Vref±δ).

Next, the reactive power Q read in via the reactive power converter 2 is controlled by the CPU 6.

(A) Q _EL <Q<Q _EH control First, the read reactive power Q is stored in RAM 8. By using the delayed maximum detection value Q _EH of the reactive power and the advanced excessive detection value Q _EL , Q _EL <Q< Controlling the Q _EH relationship.

This is done by comparing and determining Q using Q _EH and Q _EL read from RAM 8. (a) When Q > Q _EH For a certain period of time (for example, 3 seconds) in the relationship of Q > Q _EH
If this continues, the _control condition signal input via the input/output unit 9 causes the CPU ₆ to change the _shunt voltage of the input reactors, _e.g. The relay ShR _1T of the reactor control circuit 11 is energized to sequentially disconnect the shield breakers CB ₂₁ and CB ₂₂ , and then the relay of the power capacitor control circuit 10 for the tripped capacitors, for example SC ₁ and SC ₂
By energizing SC _1C and sequentially turning on circuit breakers CB ₁₁ and CB ₁₂ , the reactive power Q is adjusted to the advance side until the relationship Q<Q _EH is satisfied.

At this time, if the bus power V _B does not satisfy the relationship V _B < Vref - δ, the CPU 6 sends a step-down tap switching command from a tap switching control circuit (not shown) to change the taps of LRT ₁ to T ₄ to the step-down side. Perform the above adjustment after performing the switching operation.

(b) When Q<Q _EL The CPU 6 changes the bus voltage V _B to V _B according to the control condition signal input via the input/output section 9.
>Vref+δ, the relay SC _1T of the power capacitor control circuit 10 of the input capacitors SC ₁ and SC ₂ , for example, is energized and the circuit breaker is activated.
CB ₁₁ and CB ₁₂ are sequentially cut off, and then the relay ShR _1C of the shunt reactor control circuit 11 of the tripped reactors, such as ShR ₁ and ShR ₂ , is energized to sequentially close the breakers CB21 and CB2 ₂ . and adjust the reactive power Q to the lag side until Q> _QEL .

At this time, if the bus voltage V _B is not in the relationship of V _B > Vref + δ, the CPU 6 sends a boost tap switching command from a tap switching control circuit (not shown) to switch the taps of LRT ₁ to T ₄ to the boost side. Perform the above adjustments after operation.

(B) Control using the operating value Qop (a) In the case of a time period when the load increases rapidly If the load L increases rapidly, the CPU 6 operates according to the control condition signal input via the input/output section 9. The target value Qref is calculated by interrupting the value Qop (for example, every 0.5 seconds).
The operating value Qop is obtained from the unit capacity Qs of the reactor input in the next operation read from RAM8.
Calculate Qop = Qref + Qs / 2, and with respect to this operating value Qop, the relationship of reactive power Q is Q > Qop (Q is on the lagging side of Qop), and the bus voltage
Since V _B satisfies Vref > V _B > Vref - δ, relay ShR _1T of the shunt reactor control circuit 11 of the input reactor is excited by the CPU 6 and the input reactor is pulled through the shunt breaker. Remove it and adjust it to the forward direction.

This operation is controlled by sequentially performing this operation on the reactors that have been turned on until the reactive power Q no longer meets the relationship Q > Qop. If there is no reactor that has been turned on, the unit capacity of the next operation of the tripped capacitor is used as described above. Calculate the operating value Qop (Qop = Qref + Qs / 2) and compare it with the reactive power Q to determine whether the reactive power Q is
> Perform the above adjustment by sequentially inserting the capacitors that were tripped until the Qop is no longer relevant.

The reactive power Q adjusted in this way is
The operating value Qop is calculated and set by adding 1/2 of the unit capacity Qs of the next operation to the target value Qref, and the bus voltage V _B is controlled in the relationship of Vref > V _B > Vref - δ, so the above Bus voltage V _B to Vref±
In the time zone in which the reactive power Q increases in the lag side while maintaining the range of δ, the control can be adjusted to the advance side as much as possible.

Moreover, even though the operating value Qop is set only on the delay side, the single unit capacity of the next operation is
Since it is set by adding 1/2 of Qs, the target position
It is now possible to adjust without exceeding the symmetrical position with the operating value Qop across Qref, as if the operating value Qop was a dead zone.
It is set on both sides of Qref (Qref±
Qop) can be done in the same way as controlling.

(b) During a time period when the load suddenly decreases The CPU 6 changes the operating value Qop to the target value.
Using Qref and the unit capacitance Qs of the capacitor inserted in the next operation, calculate and set Qop = Qref - Qs / 2, and for this operating value Qop, the reactive power Q has a relationship of Q < Qop (Q is ahead of Qop). side) and the bus voltage V _B is Vref < V _B < Vref
Due to the relationship of ±δ, the relay SC _1T of the power capacitor control circuit 10 of the capacitor inserted above
is excited by the CPU 6, and the capacitor introduced via the breaker is tripped to adjust the reactive power Q to the lagging side.

This operation is controlled by sequentially controlling the input capacitors until the reactive power Q no longer satisfies the relationship Q<Qop. If there is no input capacitor, the operation will continue as described above using the unit capacity of the next operation of the tripped reactor. Calculate the value Qop (Qop
=Qref-Qs/2) and compare this with the reactive power Q, and perform the above adjustment by sequentially turning on the tripped reactors as described above until the reactive power Q no longer satisfies Q<Qop.

In this case as well, as in the case of a period of rapid increase,
While maintaining the bus voltage V _B within the range of Vref±δ, it is possible to control the operation value so that the operating value Qop is set as a dead zone between the target value Qref (Qref±Qop). Reactive power can be controlled to reduce the number of times.

(c) When the bus voltage V _B does not have a predetermined relationship In controlling the reactive power Q using the above operating value Qop, when the bus voltage V _B is Q>Qop...Vref>V _B >Vref−δ When Q>Qop...Vref <V _B <Vref+δ When the relationship does not hold, the CPU 6 sends a step-down (or step-up) tap switching command from a tap switching control circuit (not shown) provided in the input/output section 9, so that the bus voltage V _B changes to V If _B > Vref and V _B > Vref + δ, then
For Vref<V _B <Vref+δ, and for V _B <Vref,
and if V _B <Vref−δ, then Vref>V _B >Vref
Adjust the bus voltage V _B so that it becomes −δ.

These reactive power controls are repeatedly executed by the CPU 6 according to a processing program stored in the PROM 7.

(C) Setting of target values The target value Qref of reactive power control and the target value Vref of voltage control are calculated and set every extremely short fixed time (for example, 0.5 seconds) during the above operation.

As shown in FIG. 6, first, a target value Qref for reactive power control is calculated and set. That is, from the bank total current I _B read through the current converter 1, the reactive power Q _NIT when the bank total current I _B is zero and the reactance compensation X read out from the RAM 8, Qclk=Q _NIT -X・Compute I _B ² ,
Set the target value Qref from Qref=Qclk.

In addition, when you want to shift the above target value Qref due to a temporary change in the system, the suspension of phase adjustment equipment in the upper system, or a tendency for the upper system to rise excessively due to special days such as Obon holidays or New Year holidays, etc. , read out the shift amount Qsft stored in RAM8 in advance.
Reactive power control may be performed by calculating and setting Qref=Qclk+Qsft.

Next, a target value Vref for voltage control is calculated and set.
This is the bank total current I _B and the bus voltage when the bank total current I _B read from RAM8 is zero.
V _BO and feeder load center point drop compensation coefficient
Calculate Vclk=V _BO +K _B・I _B using K _B , and set Vref
= Set target value Vref from Vclk.

As mentioned above, when you want to shift the target value Vref, read out the shift amount Vsft stored in RAM8 in advance and set Vref=Vclk+Vsft.
The target value Vref may be set by

As mentioned above, in reactive power control, the target value is calculated and set by reading the bank total current at extremely short fixed intervals to minimize power transmission loss, so the conventional method of setting the target value from the predicted load Compared to the above, it is possible to perform control based on a target value that follows changes in the load. Moreover, since the target value is automatically calculated and set, there is no need to set a large number of target values in advance from the predicted load as in the past. It becomes possible to configure the unit with a smaller capacity. In addition, since the turning on/off operations of multiple power capacitors and shunt reactors are set in a rotational manner and operated in sequence, operations are concentrated on a specific switch or disconnector, causing wear and tear on the contacts. , it is possible to prevent the phase adjustment equipment from reaching the end of its life, and to make the operation of the phase adjusting equipment more frequent, thereby controlling the reactive power in a way that extends the life.

In the above embodiment, it was explained that the target value Qref is controlled without distinguishing between weekdays (Monday to Saturday) and holidays (Sunday), but since the load condition changes between weekdays and holidays, PROM7 is Processing programs for weekdays and holidays are stored, data set separately for weekdays and holidays is stored in RAM 8, and a clock signal of a clock circuit (not shown) is counted, and when a holiday comes, the holiday is automatically set. Alternatively, a processing program may be read out and executed by the CPU 6, the target values Qref and Vref may be calculated and set, and the reactive power may be controlled based on these. According to this, it is possible to more accurately control reactive power in accordance with the load situation.

According to the present invention, the operating value of reactive power control is set to the target value by adding 1/2 of the unit capacity of the power capacitor or shunt reactor operated in the next order to the target value during the load surge period. , and set it to the advanced side by subtracting it during the period of sudden load decrease, and when the reactive power exceeds this operating value, the power capacitor or shunt reactor is turned on and off to control the reactive power. Therefore, it is possible to perform control with a reduced number of operations while maintaining the bus voltage within the voltage control dead zone. Moreover, even though the operating value is set to only one side by adding or subtracting 1/2 of the unit capacity of the next operation to the target value depending on the time period of load fluctuation, the target value cannot be set. It can be controlled in the same way as if the operating values were set for both, reducing the number of times the breaker is operated, preventing wear and tear on the contacts, and performing reactive power control that extends the life of the phase adjustment equipment. be able to. Further, since the target value is set by reading the bank total current, it is possible to perform reactive power control that follows load fluctuations.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of the present invention, and Fig. 2 is an explanatory diagram of control operation. Figure B shows the operating value as 1/1 of the unit capacity of the next operation.
3 shows the case where the setting is made according to No. 3. Fig. 3 is an explanatory diagram of the control operation of the present invention, and Fig. 4 is an explanatory diagram of the control operation of the present invention.
Figure 5 is a circuit diagram showing the power capacitor control circuit installed in the input/output section in Figure 1. Figure 5 is a circuit diagram showing the shunt reactor control circuit installed in the input/output unit in Figure 1. Figure 6 is the target value setting. It is a schematic flowchart diagram explaining. 1: Current converter, 2: Reactive power converter, 3: Voltage converter, 4: Arithmetic processing unit, 7, 8: Storage unit,
9: Input/output section, 10: Power capacitor control circuit, 11: Shunt reactor control circuit, T ₁ to _{T 4} :
On-load tap-changing transformer, SC ₁ to _{SC o} : Power capacitor, ShR ₁ to _{ShR n} : Shunt reactor, CB ₁₁
〜CB _1o , CB ₂₁ 〜CB _2n : Shiya breaker.

Claims (1)

[Scope of Claims] 1. A bank current transformer that is connected to the secondary side of a plurality of on-load tap-changing transformers and sends out a bank total current, and a voltage transformer connected to the connected bank secondary bus to send out bus voltage; a plurality of power capacitors and shunt reactors each connected to the bank secondary bus through a disconnector; and a reactive power control device that adjusts reactive power by turning on and off the plurality of power capacitors and shunt reactors according to commands from the control device, the control device including the bank Calculate the reactive power target value (Qref) according to the current transformer connected from the bank current transformer, the reactive power converter connected from the bank current transformer and the voltage transformer, and the bank total current. a storage unit that stores data for the load increase period, data for the load sudden decrease period, and a reactive power calculation program, and is connected from the above-mentioned disconnector,
The operating value (Qop) of the input/output section that detects the closing/untrapping operation of the shield breaker and the load connected to the bank secondary bus during the load surge period is calculated using the following formula: Qop=Qref+Qs/2 ( However, Qref: the reactive power calculated from the bank total current sent out by the bank current transformer and the data stored in the storage unit for calculating the reactive power target value (Qref) according to the bank total current. Power target value (Qs: unit capacity of the next power capacitor to be turned on or the next shunt reactor to be tripped), and during the period of rapid load reduction of the above loads,
The operating value (Qop) is calculated using the following formula: Qop=Qref−Qs/2 (where, Qref: the bank total current sent out by the bank current transformer and the reactive power according to the bank total current stored in the storage unit) The reactive power target value calculated from the data for calculating the target value (Qref), Qs: the unit capacity of the shunt reactor to be turned on next or the power capacitor to be tripped next) is set, and the above operation is performed. The value (Qop) is compared with the reactive power (Q) sent out by the reactive power converter, and it is determined that Qop < Q during the load increase period, and Qop > Q during the load sudden decrease period. A reactive power control device comprising: an arithmetic processing section that sends a command for turning on/off operation of the power capacitor and the shunt reactor to the input/output section when a power is generated.