JPS6256732B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a voltage and reactive power control device (hereinafter referred to as a VQ device) that improves its operating efficiency.

In general, in power systems, the secondary bus voltage of electrical stations such as substations is maintained at a predetermined reference value, and the reactive power passing through high-voltage transmission lines or transformers is controlled within a specified range to reduce transmission losses. In order to reduce energy consumption and make effective use of reactive power supply facilities, load tap switching transformers (hereinafter referred to as LRTs), power capacitors (hereinafter referred to as SCs), and shunt reactors (hereinafter referred to as SRs) are installed. VQ devices are used that automatically operate voltage and reactive power adjustment devices such as

FIG. 1 shows a system configuration using such a conventional VQ device. In the figure, 1 is a high voltage bus (hereinafter referred to as a primary bus) to which a power transmission line 3 is connected via a bridge and a disconnector 2, 4 is a medium voltage bus (hereinafter referred to as a secondary bus), and 5 is a switch thereof. The primary side with the tap is connected to the primary busbar 1, and its secondary side is connected to the primary busbar 1.
The LRTs are respectively connected to the secondary bus 4, and the SC7 and SR8 are connected to the tertiary side of the LRTs via shields and disconnectors _6c and _6R . 9 introduces the current of the power transmission line 3 detected by a potential transformer (hereinafter referred to as CT) and the voltage of the primary bus 1 detected by a potential transformer (hereinafter referred to as PT) 11. This is a monitoring and control device that monitors and controls the direction and amount of power flow, as well as overvoltage, etc., using a voltmeter (not shown) and a reactive power meter. The manual operation command So of “off” is output. On the other hand, 1
2 is the VQ device, which consists of the following elements.
In other words, in the VQ device 11, 12A is the output voltage of PT11 and LRT5 detected by CT13.
This is a reactive power conversion unit that introduces the primary side current of the reactive power and converts the detected reactive power into a DC voltage proportional to the detected reactive power. Further, 12B is a calculation unit consisting of a reactive power calculation unit 12B _Q and a voltage calculation unit 12B _V. First, the reactive power calculation unit 12B _Q performs calculation with a predetermined set value based on the output signal of the reactive power conversion unit 12A. and determines the equipment to be operated based on the calculation result, and outputs the SC "on", SR "off" command signal S1 or the SC "off", SR "on" command signal S2 as the output signal of the reactive power calculating section _12BQ . It is outputted as output signals S1' and S2' via an equal frequency operation section 12C which selects and operates SC or SR based on the . The voltage calculation unit 12B _V performs calculations with a predetermined set value based on the voltage of the secondary bus 4 detected by the PT 14, and based on the calculation result,
LRT5 tap “up” and “down” operation command signal S
This outputs 3.

In such a configuration, the power flow direction of the power transmission line 3 is normally the power receiving direction R, and the voltage of the primary bus 1 detected by the PT 11 and the primary current of the LRT 5 detected by the CT 13 are The voltage is applied to the reactive power conversion unit 12A of the VQ device 12, where it is converted to a DC voltage and applied to the reactive power calculation unit _12BQ . In this reactive power calculation section _12BQ ,
An operation is performed between the applied DC voltage signal and the set value, and based on the result of the operation, an SC, SR "on" or "off" command S1 or S2 is applied to the equal-frequency operation section 12C. Finally, the output signal is connected to the tertiary side of LRT5.
The reactive power is controlled to the target value by controlling the breaker _6c or _6R of SC7 and SR8 to open or close at regular intervals. On the other hand, the voltage of the secondary bus 4 detected by the PT14 is applied to the voltage calculation section 12B _V of the VQ device 12, where calculation is performed between it and the set value, and based on the calculation result, the LRT5
Outputs the “up” and “down” operation commands S3 of the tap,
As a result, the secondary bus voltage is controlled to the target value by operating the tap "up" or "down".

On the other hand, in the above, when the tidal flow direction of the power transmission line 3 changes from the power reception direction R to the power transmission direction S, for example at night, and a tidal amount greater than a predetermined tidal amount is detected through the CT 10 and the PT 11,
This fact is monitored by the supervisory control device 9, and upon confirmation by the operator, reactive power control by the VQ device 12 is manually locked. After that, compensation for the invalid portion of the power transmission flow is
The operator manually turns SC and SR on and off while constantly monitoring the reactive power meter of the supervisory control device 9.
This is dealt with by performing operations. However, the fact that the operator has to simultaneously monitor the amount of power, its direction, and overvoltage, and perform operations to deal with it, increases the workload of the operator in terms of monitoring and control, making it difficult for the operator to concentrate on operations. This is not desirable as it may lead to mistakes. In addition, in this case, since the phase adjustment equipment is operated directly without going through the isochronous operation unit, it is possible to “turn on” only a certain SC or SR by the operator's operation.
This is undesirable because it will result in a "cut" operation, which will shorten the life of only a specific SC and SR shield out of the phase modifier equipment group. Furthermore, for the reasons mentioned above, it is impossible to increase the number of phase modifier facilities to be controlled.

The present invention has been made in view of the above-mentioned circumstances, and is aimed at reducing the secondary system bus voltage of a plurality of on-load tap-changing transformers installed in an electrical station such as a substation, and the total reactive power of the on-load tap-changing transformers. In a voltage/reactive power control device that automatically and equally frequently operates a group of phase modifiers having a power capacitor and a shunt reactor to control it to a predetermined target value, operator monitoring is required. An object of the present invention is to provide a highly reliable voltage and reactive power control device that can save labor in operating operations and improve phase adjustment control efficiency.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 shows a system configuration of a VQ device equipped with power flow and overvoltage control functions. The same parts as in FIG. In the figure, 15 is equipped with a low, medium, and high level power flow rate (not shown), a power transmission direction S detection relay, and an overvoltage detection relay, and based on the output signals of CT10 and PT11, low L, medium M, and high H levels in the power transmission direction Tidal flow rate and set value V
A tidal flow/direction/overvoltage detection section that detects an overvoltage of _R or more outputs the output through an operation determination section 16 (details of which will be described later).
The normally open contact 17a ₁ of the auxiliary relay 17 for SC "on" and SR "off" commands (hereinafter simply referred to as command A) for SC "on" and SR "off" command signals (hereinafter simply referred to as command A) is also connected when a decrease in the tidal flow rate is detected. and SC “off” when overvoltage is detected, SR
The "on" command signal (hereinafter simply referred to as command B and command B') is operated at equal frequency via the normally open contact 18a ₁ of the auxiliary relay 18 for SC "off" and SR "on" commands, which will be described later. Add to section 12c. Furthermore, the output signal S1 of the reactive power calculation unit 12B _Q in FIG.
S2 is the power flow rate/direction, and each normally open contact of the low level L power flow detection relay 19L (not shown) of the overvoltage detection unit 15 is a normally closed contact amplified by an off-delay timer having a time limit _t1 '. 1
Through 9'Lb ₁ and 19'Lb ₂ , isochronous operation section 1
This is added to 2c.

FIG. 3 shows a detailed circuit configuration of the operation determining section 16, in which P and N are control power supply buses. 2
Reference numeral 0 designates a low-level power flow detection keep relay that includes an operating coil 21, a return coil 22, and a switching contact 23 for switching between the two. Reference numeral 24 designates an off-delay timer 25 having a time limit t ₁ connected in parallel, and an on-delay timer having a time limit t ₂ connected in parallel to the contact 22b for excitation closing of the return coil 22 and the low level power flow detection relay 19L.
Normally open contacts 19La are connected in series and provided between the control power supply buses P and N. Here, the time limit _t2 of the on-delay timer 24 is at least the time (approximately 5 seconds) required for the isofrequency operation section 12c to receive an operation command, determine the operation device from this, and send out the operation output. Further, the time limit _t1 of the off-delay timer 25 is set to a time (approximately 0.1 to 0.5 seconds) for achieving time coordination between relays, which will be described later. 26 is an on-delay timer to which an off-delay timer 27 having a time limit t ₁ similar to the above is connected in parallel, and an on-delay timer having a time limit t ₂ similar to the above;
Contact 21 that closes when the operating coil 21 is energized
a ₁ , a normally closed contact 28b of an off-delay timer 28 (described later), a contact 29b that closes when energized of a return coil 29 (described later), and a normally closed contact 19Lb ₃ of the low-level power flow detection relay 19L are connected in series for control. Installed between power bus lines P and N. In addition, in the above, one end of the operating coil 21 of the low-level power flow detection keep relay 20 is connected to the other control power supply bus N via its switching contact 23, and the other end is connected to the normally open contact 24a of the on-delay timer 24. The contacts 19La and 22b are connected through the contact points 19La and 22b, respectively. Further, one end of the return coil 22 is connected to the other control power supply bus N through the switching contact 23, and the other end is connected to the contact 2 through the normally open contact 26a of the on-delay timer 26.
Connect between 8b and _21a1 , respectively. On the other hand, 30 is a keep relay for medium level power flow detection, which is equipped with an operating coil 31, a return coil 29, and a switching contact 32 for switching between the two. 33 is a time limit
An off-delay timer 34 having a time limit of t ₁ ' is connected in parallel, and an on-delay timer having a time limit of t ₂ ' includes a contact 29b that closes when the return coil 29 is energized, and a normally closed contact 25b of the off-delay timer 25. , the normally open contact _21a2 of the operating coil 21 and the normally open contact 35Ma of the medium level power flow detection relay 35M (not shown) of the power flow rate/direction and the overvoltage detection unit 15 are connected in series, and the power flow is connected between the control power supply buses P and N. establish. Here, the time limit t ₂ ' of the on-delay timer 33 is the time (approximately 5 seconds), and the time limit t1' of the off-delay timer ₃₄ is set to a time (approximately 0.1 to 0.5 seconds) for achieving time coordination between relays, which will be described later, in the same way as described above. 36 is the same time limit as above
An off-delay timer 28 having a time limit of t ₁ ' is connected in parallel, and an on-delay timer having a time limit of t ₂ ' similar to the above is connected, and a contact 31a that closes when the operating coil 31 is energized corresponds to a high level H (not shown). A normally closed contact 37b of the off-delay timer 37 provided as a switch, a contact 38b that closes when energized of a return coil 38 of a keep relay provided corresponding to the high level H (not shown), and the medium level tidal flow rate detection relay 35M. Normally closed contacts of 35 Mb are connected in series and installed between the control power supply buses P and N. In addition, in the above, keep relay 3 for medium level tidal flow detection
0 operating coil 31 to its switching contact 32.
and the other end is connected to the other control power bus N through the normally open contact 33a of the on-delay timer 33 between the contacts 25b and 29b, respectively.
Further, one end of the return coil 29 is connected to the other control power supply bus N via the switching contact 32, and the other end is connected to the normally open contact 36a of the on-delay timer 36 between the contacts 37b and 31a. on the other hand,
17 is an auxiliary relay for SC “on” and SR “off” commands.
The self-holding contact 17a ₂ is connected in parallel to the normally closed contact 39b of an auxiliary relay for SC "on" and SR "off" limit detection (not shown), and the above-mentioned off-delay timer 3.
The normally open contact 25a of the off-delay timer 25, in which the four normally open contacts 34a are connected in parallel, and the LRT
Contact 4 that closes under the condition that 5 is the bank to be controlled
0a ₁ , the flow rate/direction, and the normally closed contacts 41b of the overvoltage detection relays, which are equal to or higher than the unillustrated set value V _R of the overvoltage detection unit 15, are connected in series and provided between the control power supply buses P and N. Reference numeral 18 denotes an auxiliary relay for SC "off" and SR "on" commands, and its self-holding contact 18a ₂ is connected in parallel to a normally closed contact 42b of an auxiliary relay for SC "off" and SR "on" limit detection (not shown). One is connected between the contacts 40a and 25a via the backflow prevention diode 43 and the normally open contact 27a of the off-delay timer 27 to which the normally closed contact 28a of the off-delay timer 28 is connected in parallel; The other is the normally open contact 4 of the overvoltage detection auxiliary relay 44, which will be described later.
4a, and a contact _40a2 having the same function as the above-mentioned normally open contact _40a1 , it is connected to one control power supply bus P. Further, 45 is an overvoltage detection keep relay that includes an operating coil 46, a return coil 47, and a switching contact 48 for switching between the two.
Reference numeral 49 denotes an on-delay timer having a time limit of _t3 , and the contact 4 closes when the return coil 47 is energized.
7b, above, normally open contact 41a of overvoltage detection relay
are connected in series and provided between control power supply buses P and N. Here, the time limit _t3 is set to a time (approximately 20 to 30 seconds) to prevent temporary overvoltage detection caused by raising the tap of the LRT5 too much. Also,
50 is the above-mentioned on-day delay timer 24, 26, 3
An on-delay timer having the same time limit t ₂ ″ as in 3 and 36 is connected in series with the contact 46a ₁ that closes when the operating coil 46 is energized, and the control power bus P,
Provided between N. Further, in the above, one end of the operating coil 46 of the overvoltage detection keep relay 45 is connected to the other control power supply bus N via its switching contact 48.
In addition, the other end is connected via the normally closed contact 49a of the on-delay timer 49 between the contacts 41a and 47b, respectively. Furthermore, one end of the return coil 47 is connected to the other control power supply bus N via the switching contact 48, and the other end is connected to the normally open contact 50 of the on-delay timer 50.
They are respectively connected to one control power supply bus P via a. 44 is an overvoltage detection auxiliary relay, which connects the normally open contact 46a ₂ of the operating coil 46 and the normally open contact 4.
A contact 40a ₃ having the same function as 0a ₁ and 40a ₂ is connected in series and provided between the control power supply buses P and N.
In addition, in the above, the time limit t ₁ , t ₁ ' is the contact point 35
This is a time setting that prevents the on-delay timer 33 and off-delay timer 34 from being energized at the same time as Ma, 21a ₂ is closed.

Next, the operation of the VQ device having such a configuration will be explained with reference to FIG. In addition, in Fig. 4, the horizontal axis represents the amount of power, the vertical axis represents the amount of voltage, and L, M, H
are the low, medium, and high level power flow setting values, and V _R is the overvoltage setting value, respectively. In addition, A represents the range of no tidal flow and low-level tidal flow, and B, C, and D represent the low, medium, and high-level tidal current ranges, respectively.

First, a normal case where the power flow direction of the power transmission line 3 is the power receiving direction R will be described. In this case, the power amount/direction and overvoltage detection section 15 is provided with:
Each of the tidal flow/direction detection relays and overvoltage detection relays (not shown) do not operate at any time, and their output signals are not applied to the operation determination section 16. In other words, since the low and middle level power flow detection contacts 19La and 35Ma and the overvoltage detection contact 41a are all open, and the power flow detection contacts 19'Lb ₁ and 19'Lb ₂ are both closed, the operation determination unit 16 No output signal is sent. On the other hand, the voltage of primary bus 1 detected by PT11 and LRT5 detected by CT13
The primary side current is applied to the reactive power converter 12A of the VQ device 12', where it is converted to a DC voltage and applied to the reactive power calculator _12BQ . In this reactive power calculation section _12BQ , calculation is performed between the applied DC voltage signal and the set value, and based on the calculation result, SC "on", SR "off" command S
1 or SC "off" and SR "on" commands S2 are applied to the equally frequent operating section 12C through the contacts 19'Lb ₁ or 19'Lb ₂ . Finally, the output signal S1' or S2' from the equal frequency operation section 12C causes the SC connected to the tertiary side of the LRT5 to
7. The reactive power is controlled to the target value by controlling the SR8 shield breaker _6c or _6R to open or close at regular intervals. On the other hand, the voltage of the secondary bus 4 detected by the PT14 is applied to the voltage calculation section 12B _V of the VQ device 12', where calculation is performed between it and the set value, and based on the calculation result, the LRT5 A command S3 for operating the tap "up" or "down" is output, and the secondary bus voltage is controlled to the target value by operating the tap "up" or "down".

Next, a case where the power flow direction of the power transmission line 3 becomes the power transmission direction and becomes equal to or higher than the low level L power flow rate will be described. Now, when the power flow direction of the power transmission line 3 changes from the power reception direction R to the power transmission direction S, and the power flow reaches the low level setting value L, the power flow, direction, and low level power flow (not shown) of the overvoltage detection unit 15 are detected. The detection relay operates and its contact 19La is closed or contact 1 is closed.
9′Lb ₁ , 19Lb ₂ , and 19Lb ₃ are opened, respectively. As a result, the output signals S1 and S2 of the reactive power calculation unit 12A obtained through the same process as described above are
Blocked by 9Lb ₁ and 19Lb ₂ , that is, VQ device 1
2' is locked. Also, by opening the contact 19La, the on-delay timer 2
4 and off-delay timer 25 are connected to contact 19
It is excited through La, 22b. First, when the off-delay timer 25 is excited, its normally open contact 25a is closed, and when the overvoltage detection relay is not activated, its normally closed contact 41b is closed, and the conditional contact 40a whose control bank is connected to the target bus ₁
Closed circuit, SC “on”, SR “off” limit detection relay is not activated, its normally closed contact 39b is closed, and contact 41
SC “in” through b, 40a ₁ , 25a, 39b,
The SR “off” command relay 17 is energized. Then, due to this operation, the contact 17a ₂ closes and holds itself, and the contact 17a ₁ closes and the operation determination unit 16 makes the SC "on" through the contact 17a ₁ .
An SR "off" command signal A is applied to the equal frequency operating section 12C. As a result, when t ₂ hours have elapsed, the equal frequency operation unit 12C outputs an operation signal of SC "ON" or SR "OFF" to the operation circuit (not shown).
S ₁ ' is sent out, which causes one SC7 to be turned on or one SR8 to be tripped to control the increase in low level power flow. on the other hand,
The on-delay timer 24 operates after at least t ₂ hours have elapsed since its energization, and its normally open contact 24a
is closed, and the operating coil 21 of the keep relay 20 is excited. As a result, the contact 22b is opened, the on-delay timer 24 and the off-delay timer 25 are deenergized, the contacts 24a and 25a are opened, and the contacts 21a ₁ and 21a ₂ are closed. Also,
When the increase in the power flow in the power transmission line 3 exceeds the low level power flow range B from the low level L and further reaches the medium level set value M, the medium level power flow detection relay similarly operates and its contact 35Ma closes. 35Mb is opened. As a result, the contact 35Ma, the normally open contact 21a ₂ of the operating coil 21, the off-delay timer 2
The on-delay timer 33 and the off-delay timer 34 are connected through the normally closed contact 25b and the contact 29b of No.
is excited. After that, through the process completely similar to the operation of detecting the low level L tidal flow rate described above, the contact 41b,
SC “in” through 40a ₁ , 34a, 39b, SR
The “off” command relay 17 is energized. As a result, as described above, the contact 17a ₂ is self-held, and the operation determination unit 16 applies the SC “on” and SR “off” command signal A to the constant frequency operation unit 12C through the contact 17a ₁ . After ₂ ' time has elapsed, one SC7 is turned on or one SC7 is turned on as described above.
By tripping SR8, control for the increase in medium-level tidal flow is performed. On the other hand, similarly, the on-delay timer 33 is at least
After the t ₂ ' time elapses, the normally open contact 33a
is closed, and the operating coil 31 of the keep relay 30 is excited. As a result, the contact 29b is opened, the on-delay timer 33 and the off-delay timer 34 are deenergized, the contacts 33a and 34a are opened, and the contact 31a is closed.

Next, a case will be described in which the tidal flow rate of the power transmission line 3 decreases in such a state and reaches the low level tidal current range B from the medium level tidal current range C. now,
When the tidal flow reaches the intermediate level setting value M or less, the aforementioned intermediate level tidal flow detection relay returns to its original state, and its contact 35Mb is closed and its contact 35Ma is opened. As a result, the on-delay timer 36 and the off-delay timer 28 are excited through the contacts 35Mb, 38b, 37b and the normally open contact 31a of the keep-relay operating coil 31. First, when the off-delay timer 28 is excited, its normally open contact 28a is closed, and when the overvoltage detection relay is inoperable, its contact 41b is closed, and the conditional contact 40a ₁ , where the control bank is connected to the target bus, is closed. , S.C.
"OFF", SR "ON" limit detection relay is inoperable, its normally closed contact 42b is closed, and contacts 41b, 40
The SC "off" and SR "on" command relay 18 is energized through a ₁ , 28a, the diode 43, and the contact 42b. Then, due to this operation, the contact 18a ₂ closes and holds itself, and the contact 18a ₁ closes and the operation determination unit 16 passes the SC through the contact 18a ₁ .
"OFF", SR "ON" command signal B is equal frequency operation part 1
Added to 2c. Then, when time _t2 ' has elapsed from this point, the equal-frequency operation unit 12C sends an operation output S2' of SC "off" or SR "on" to an operation circuit (not shown), thereby increasing the tidal flow. The same number of SC7s as at the time of detection, that is, one SC7 is tripped or one SR8 is turned on to control the medium level M power flow reduction. On the other hand, the on-delay timer 36 operates after at least t ₂ ' time has elapsed since its excitation, and its normally open contact 36a is closed, and the return coil 29 of the keep relay 30 is energized. This opens the contact 31a, deenergizes the on-delay timer 36 and the off-delay timer 28, opens the contacts 28a and 36a, or closes the contact 28b, and the contact 29b
is closed, and contact 31a is opened. In addition, when the decrease in the power flow of the power transmission line 3 goes from the low level power flow range B, exceeds the low level set value L, and further reaches the low level L and no power flow range A, the low level power flow detection relay described above is activated. returns, and the contact 19La is opened and the contact _19Lb3 is closed. This causes contact 19
The on-delay timer 26 and the off-delay timer 27 are excited through Lb ₃ , 29b, 28b and the normally open contact 21a ₁ of the operating coil 21 of the keep relay 20. First, when the off-delay timer 27 is excited, its normally open contact 27a is closed, and when the overvoltage detection relay is inoperable, its contact 41b is closed, and the conditional contact 40a ₁ , where the control bank is connected to the target bus, is closed. , SC “cut”, SR
Due to the "ON" limit detection relay not operating, its normally closed contact 42b is closed, and the contacts 41b, 40a ₁ , 27a,
SC “off” through diode 43 and contact 42b,
The SR "on" command relay 18 is energized. Then, due to this operation, the contact 18a ₂ closes and holds itself, and the contact 18a ₁ closes and the operation determination unit 16 outputs the SC "off" SR through the contact 18a ₁ .
An "on" command signal B is applied to the isochronous operation section 12C. Then, after a time _t2 ' has elapsed, the equal frequency operation unit 12C outputs an operation output S of SC "off" or SR "on" to the operation circuit (not shown).
2' is sent out, and thereby the same number of units as at the time of detecting the increase in the tidal flow rate, that is, one SC7 is tripped or one SR8 is turned on, thereby performing control for the decrease in the medium level M tidal flow rate. On the other hand, the on-delay timer 26 is at least
The normally open contact 26a is activated after the t ₂ ' time has elapsed.
is closed, and the return coil 22 of the keep relay 21 is energized. As a result, the contact 21a ₁ is opened, the on-delay timer 26 and the off-delay timer 27 are deenergized, the contacts 27a and 26a are opened, and the contact 21a ₁ is also opened. On the other hand, in the above case, after the time t ₂ ' has elapsed, the contacts 19Lb ₁ and 19Lb ₂ are simultaneously closed to release the lock, and when the control operation for the low level power flow reduction is completed, the normal VQ device 12' is activated. Return to normal operation.

Next, a case will be described in which an overvoltage equal to or higher than the set value _VR occurs on the primary bus 1, as shown in FIG. 4A, when the low level L power amount is detected. Now, when an overvoltage occurs on the primary bus 1 when detecting the low level L tidal flow of the power transmission line 3, the overvoltage detection relay (not shown) of the tidal flow/direction/overvoltage detection section 15 operates, and its contact 41b opens or closes. The contacts 41a are respectively closed. Then, first, by opening the contact 41b, the operation of each command relay 17, 18 is locked, that is, the phase adjustment control for the increase in low-level power flow is locked, and by closing the contact 41a, the on-delay timer 49 for overvoltage detection is activated by the closing of the contact 41a. ,47
It is excited through b. If this overvoltage occurs,
Unless it is caused by a temporary problem such as excessively raising the tap of the LRT 5, the on-delay timer 49 operates when _t3 hours have elapsed since the energization. Then, the contact 49a closes and the operating coil 46 of the overvoltage detection keep relay 45 is energized, and the contact 47b opens and the on-delay timer 49 is deenergized. At the same time, contact 46
a, 46a ₂ are closed, and the overvoltage detection auxiliary relay 44 is connected through contacts 40a ₃ and 46a ₂ , and contact 46a ₁
The on-delay timers 50 are excited through the respective on-delay timers 50. First, the overvoltage detection auxiliary relay 44 operates and the contact 44a closes, so that the control target bank connection condition contact 40a ₂ , the contact 44a, SC "off",
Through the SR "on" limit detection relay contact 42b,
The relay 18 for SC “off” and SR “on” commands is energized. Then, due to this operation, the contact 18a ₂ closes and maintains itself, and the contact 18a ₁ closes, and the operation determination unit 16 causes the SC to pass through the contact 18a ₁ .
"OFF" and SR "ON" command signals B' are applied to the equal frequency operating section 12C. Thereafter, through the same process as described above, one SC7 is tripped or one SR8 is turned on, thereby controlling overvoltage generation. On the other hand, the on-delay timer 50 operates after at least t ₂ '' time has elapsed since its excitation, and its normally open contact 50a is closed, and the return coil 47 of the keep relay 45 is energized.
a ₁ , 46 a ₂ are opened, the on-delay timer 50 and the overvoltage detection auxiliary relay 44 are deenergized, and the contact 50 is opened.
a, 44a are opened, the contact 44a is also opened, and the auxiliary relay 18 is deenergized. On the other hand, if the overvoltage continues to occur even after performing the above control operation, the contact 41a remains closed, so the on-delay timer 49 is energized again through the contacts 41a and 47b, and the same process as described above occurs. After the process, one more SC7 trip or SR8
input is made. In this way, the operation of tripping the SC7 or closing the SR8 is performed at regular intervals through the constant frequency operation section 12C until the voltage of the primary bus 1 returns to the normal voltage. When the overvoltage is recovered, the overvoltage detection relay returns to its original state, opening the contact 41a and closing the contact 41b to release the lock on the phase adjustment control due to the increase in the amount of low-level power, and thereafter repeat the same process as described above. After that, the phase adjustment control for the increase in the tidal flow rate continues to be performed.

In addition, in the above, the increase in the power flow rate of the power transmission line 3 from the low level L to the medium level M is detected within t ₂ hours after the detection of the low level L, that is, SC "on" and SR " due to low level detection. Even if it is detected before the output of the "off" operation command S1' and the intermediate level power flow detection contact 35Ma is closed, the contact 25b of the off-delay timer 25 is open at this point, and the deenergization causes the return. is performed after t ₁ hour has elapsed, so the control commands for SC7 and SR8 based on low level L tidal flow detection and medium level tidal flow detection are not output at the same time, and as mentioned above, low level L tidal flow After the control for the intermediate level M is completed, the control for the middle level M is performed. On the other hand, since the control for detecting the high level H tidal flow rate is exactly the same as described above, a description of the detection and control will be omitted. Further, since the operation in response to a decrease in the tidal flow rate (return) is completely the same, the explanation thereof will be omitted. Furthermore, in the above case, if an overvoltage occurs on the primary bus 1 while detecting an increase or decrease in the medium or high level power flow (the control shown in Figure 4 C and E will be applied when an increase or decrease in the low level power flow is detected). Since this is exactly the same as control, the explanation thereof will be omitted.

In this way, two of the LRT5s installed at the substation
A VQ in which the voltage of the secondary bus 4 and the reactive power of the LRT 5 are controlled to predetermined target values by automatically operating a phase adjustment equipment group having a plurality of SC7s and SR8s through the equal frequency operation unit 12C. In the device, a power flow rate/direction and overvoltage detection unit 15 for detecting the power flow rate and direction and overvoltage of the power transmission line 3 connected to the primary bus 1 of the LRT 5 is provided in the device, and the power flow of the power transmission line 3 is detected in the receiving direction. When it is detected that the power transmission direction has changed from R to S and that the power flow has reached the low level L of the predetermined low, medium, and high levels L, M, and H, the reactive power calculation unit 12B _Q of the VQ device 12'
After locking the reactive power control by the output of ) minutes SC “on”, SR “off”
The operation command A is applied from the operation determination unit 16 to the constant frequency operation unit 12C at any time on the condition that the operation for the previous level is completed, and the SC7 and SR8 sheath disconnectors 6 _C 6 _R are continuously adjusted to the constant frequency. Control. Also, when the power flow rate decreases (returns) at each level, the SC "off" and SR "on" operation commands are similarly given for a predetermined number of units (one unit) each time the level H, M, and L power flow rates are detected. B is added to the equal-frequency operation section 12C and the operations are performed sequentially, and when the flow rate decreases (returns) to below the low level power flow L, the output of the reactive power calculation section 12B _Q is The reactive power control is released from the lock and the automatic control operation by the VQ equipment 12' is returned to. Furthermore, during the above operation by detecting the increase or decrease of the power flow, the primary bus 1
When an overvoltage occurrence is detected, the phase adjustment control based on the power flow rate detection described above is immediately locked, and the SC “off” and SR for a predetermined number of units (one unit) are
The "on" operation command B' is applied to the equal-frequency operation section 12C, and operations for the occurrence of overvoltage are sequentially performed with priority until the overvoltage returns to normal voltage, and when the voltage returns to normal voltage, the above-mentioned power flow rate detection is performed. The lock of the phase adjustment control is released and the control based on the detection of the tidal flow rate is continued again.

Therefore, monitoring and control of the power flow rate, direction, and overvoltage of the power transmission line 3 can be performed stepwise and automatically for each level L, M, and H, so that changes in the power flow rate in the power transmission direction S can be avoided as in the conventional method. There is no need for operator monitoring and manual operation to carry out phase adjustment control in response to overvoltage generation, which greatly reduces the operator's monitoring work and improves automatic operation efficiency. In addition, whatever the power flow rate and direction of the power transmission line 3, phase adjustment control can be performed through the equal-frequency operation unit 12C, which averages out _the life of the phase adjustment equipment's shields and breakers _6C6R . can do. Furthermore, since the tidal flow rate can be automatically monitored and controlled as described above, it is possible to increase the number of phase modifier facilities to be controlled, which has been difficult in the past.

Note that the present invention is not limited to the above embodiments.

(1) Each off-delay timer 2 in the above embodiment
Even if auxiliary relays 5, 27, 34, and 28 are replaced with auxiliary relays that require time corresponding to the time limits t ₁ and t ₁ ' to return, the same implementation can be achieved.

(2) In the above embodiment, the case where the number of control phase modifiers for medium and high level power flow is one each is described, but in the case where two units are controlled due to the capacity of the phase modifier, etc. A similar implementation can be achieved by providing two circuits for detecting an increase/decrease in the amount of power for each level, corresponding to the number thereof. In addition, the present invention can be implemented with various modifications without changing the gist thereof.

As explained above, according to the present invention, the secondary system voltage of a plurality of on-load tap-changing transformers and the total reactive power of on-load tap-changing transformers provided in an electrical station such as a substation are transferred to a power capacitor and a shunt. In a voltage reactive power control device that automatically and equally frequently operates a group of phase adjustment equipment having a reactor to control it to a predetermined target value, a power flow/direction detection control section and an overvoltage detection control section are provided. The system is designed to detect increases and decreases in the tidal flow rate step by step for each level, and perform phase adjustment control on the tidal flow rate equally frequently and automatically.When overvoltage is detected, the tidal flow control is locked and overvoltage control is performed. Since priority is given to automatic operation, it is possible to provide a highly reliable voltage and reactive power control device that can save the operator's effort in monitoring operations and improve phase adjustment control efficiency.

[Brief explanation of the drawing]

Figure 1 shows the configuration of a conventional VQ device, Figure 2 shows the configuration of a conventional VQ device.
The figure is a configuration diagram showing an embodiment of the VQ device of the present invention.
FIG. 3 is a circuit diagram showing the detailed configuration of the operation determining section in FIG. 2, and FIG. 4 is a diagram for explaining the operation of the present invention. 1...Primary bus bar, 2,6 _C , 6 _R ...Shiya disconnector,
3...Power transmission line, 4...Secondary bus, 5...LRT,
7...SC, 8...SR, 9...Monitoring control device, 1
0,13...CT, 11,14...PT, 12...
VQ device, 12A...Reactive power converter, 12B _Q ...
...Reactive power calculation section, 12B _V ...Voltage calculation section, 1
2C... Equal frequency operation section, 15... Tidal flow/direction/overvoltage detection section, 16... Operation determination section, 17...
...Relay for SC "on", SR "off" command, 18...
SC “off”, SR “on” command relay, 17a ₁ , a ₂ …
... 17 contacts, 18 a ₁ , a ₂ ... 18 contacts, 19
La, 19Lb ₁ ~ ₃ ... 19L contact, 20, 3
0,45...Keep relay, 21,31,46...
...Operating coil, 22, 29, 47... Return coil, 23, 32, 48... Switching contact, 24, 2
6, 33, 36, 49, 50...On-delay timer, 25, 27, 34, 28...Off-delay timer, 35Ma, Mb...35M contact, 37
b, 38b...37, 38 contacts, 39b...3
9b contact, 40a ₁ to ₃ ...40 contact, 41
a, 41b...41 contact, 42b...42 contact, 43...backflow prevention diode, 44...overvoltage detection auxiliary relay, 44a...44 contact, 4
9a...49 contacts, 50a...50 contacts.

Claims (1)

[Claims] 1. Detect the reactive power and secondary system bus voltage of a plurality of on-load tap-changing transformers installed in an electrical station such as a substation, and apply it to the taps of the on-load tap-changing transformer and its tertiary winding or the A voltage reactive device that is connected to a secondary system bus, etc. and has a power capacitor and a shunt reactor and is controlled to a predetermined set value by operating the phase adjusting device at a predetermined frequency using the output of the voltage and reactive power calculation unit. In a power control device, the power flow direction and the increase and decrease of the power flow amount of the power transmission line connected to the primary system bus of the on-load tap switching transformer are detected in stages at each predetermined setting level. - A direction detection section and an overvoltage detection section that detects an overvoltage higher than a set value of the primary system bus are provided, and when the tidal amount increases, the tidal amount
When the direction detection unit detects power flow in the power transmission direction and a power flow rate higher than the low level, the control by the output of the reactive power calculation unit is locked and a predetermined number of power capacitors are turned on or the shunt reactor is pulled. When the power flow rate decreased, the same number of power capacitors as the power capacitors were tripped or the shunt reactor was turned on when the power flow rate decreased, and a power flow rate below the low level power flow rate was detected. If an overvoltage is detected by the overvoltage detection section during the detection of an increase or decrease in the power flow rate of each level, the output of the reactive power calculation section is unlocked. The power flow control is locked, and the power capacitor tripping or shunt reactor closing control is performed until the normal voltage is restored, and when the normal voltage is restored, the power flow control is unlocked and the power flow at each level is adjusted again. A voltage reactive power control device characterized by continuing power flow control according to the amount of power.