JP3327835B2 - System voltage stabilizer with reactive power compensator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a reactive power compensator for compensating reactive power of a power system by using a power capacitor, a reactor or an inverter. The present invention relates to a system voltage stabilizing device that operates to stabilize voltage fluctuations of a power system.

[0002]

2. Description of the Related Art In an electric power system, since impedance always exists from a power supply side to a load point, if a load current increases, a line voltage drop occurs accordingly, and a voltage at the load point drops. In such a power system in which the voltage at the load point drops, a voltage regulator is generally installed in order to keep the voltage supplied to the load within a certain voltage range. In this type of voltage regulator, the peak and
Since the current ratio at the off-peak time greatly affects and varies depending on the region and the season, it is necessary to comprehensively judge these factors and consider voltage adjustment.

[0003] Conventionally, a line voltage regulator (SVR: Step Voltage Reg) generally used.
ulrator) is known. This SVR is provided with an adjusting transformer at a place where the voltage fluctuation of the power system is large, and by switching taps provided on the adjusting transformer, the voltage input from the power input side is reduced on the load side. Is increased in advance, and the voltage on the load side is set to a voltage within a certain range to compensate for the voltage drop due to the load.

[0004] Such an SVR has a drawback that it is not possible to adjust the voltage corresponding to an instantaneous change in the situation, because the purpose is to deal with a gradual voltage change due to a daily load change or the like. In addition to such a voltage compensation function of the SVR, a static var compensator (SVC: Static Var Comp) applying a power electronics technology capable of controlling reactive power of a power system at high speed.
Encoder) has been used. As one type of such SVC, TSC (Thyristor-
Switched Capacitor method or SVG (Static Var Generator)
There is something like a scheme.

[0005]

When a static var compensator, such as the SVG system, is connected to a power system, first and second power supplies L and L are connected to the power system L as shown in FIG. And the second switches 61 and 62 with sensors, and the first and second switches 61 and 62 with sensors.
A third switch 63 is connected in parallel with the first switch 63, and an SVG device 50 including an inverter and a control circuit for sending a control signal to the inverter is connected via the third switch 63. Further, the third switch 63 is connected to a monitoring slave station 70 having an SOG relay 71 and a communication unit 72.

Then, in the SVG device 50,
When an accident such as a ground fault occurs on the SVG device 50 side from the third switch 63, the sensor of the switch 63 with the third sensor (in this case, a zero-phase current transformer (ZCT)) causes a ground fault. It detects and sends a ground fault signal to the SOG relay 71 of the monitoring slave station 70. Then, based on the ground fault signal, the SOG relay 71 excites the trip coil provided in the third switch 63, and opens the contact of the third switch 63, so that S
When a ground fault occurs on the VG device 50 side, the power system L
It is designed to be separated so as not to affect.

However, as described above, the first and second switches 61 and 62 with sensors are respectively connected to the power supply side and the load side of the power system L, and the first and second switches with sensors are connected. A third switch 63 is connected in parallel to 61 and 62, and the SVG device 50 is connected to the third switch 63. For this reason, three switches, ie, the first and second switches 61 and 62 with sensors and the third switch 63, are required, which causes a problem that this type of device becomes expensive. Further, the first and second switches 61 and 62 with sensors are provided.
Are connected in series to the electric power system L, so that the work for connecting this type of device is troublesome and complicated.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and is intended to provide a reactive power compensator to a power system by using one switch. It is an object of the present invention to make it possible to protect a power system from a ground fault on the reactive power compensator side.

In order to achieve the above object, the present invention
If the system voltage fluctuates, the voltage fluctuation of the same power system will be reduced.
System voltage stabilizer with reactive power compensator
A reactive power supply connected to the power system via a switch.
Connect the power compensator and change the state of the power system
Monitor and report the monitoring status by communication with the master station
Connected to the switch, and the reactive power compensator is connected to the switch.
A main circuit section for compensating the reactive power of the power system;
Controls the operation of the main circuit and detects abnormalities in the main circuit.
And a control circuit for outputting an abnormality in the main circuit section.
Simulated ground fault signal generation that generates a simulated ground fault signal when detected
And a simulated ground fault signal generation unit
Zero phase that outputs a ground fault signal in response to the generated simulated ground fault signal
A current transformer and the reactive power compensator connected to the power system
A trip coil that opens and closes the contact
A simulated ground where a current transformer is sent from the simulated ground fault signal generator
When a ground fault signal is detected, a ground fault signal is output.
The monitoring slave station trips the trip coil based on
The trip signal is sent, and the trip signal
The coil is excited to open the switch.
System voltage reduction provided with a reactive power compensator
A stabilizing device is provided.

[0010]

The system voltage stabilizing device constructed as described above.
In, the zero-phase current transformer detects the simulated ground fault signal sent from the simulated ground fault signal generator and outputs a ground fault signal, and the monitoring slave station sends a trip signal to a trip coil based on the ground fault signal. Is transmitted, the trip coil is excited by the trip signal, and the switch can be opened. Therefore, even when an abnormality occurs inside the reactive power compensator, the reactive power compensator is not connected to the power system, so that it is possible to prevent the power system from being adversely affected.

Furthermore, when the switch is provided with a voltage detection sensor and a current detection sensor, the reactive power compensator calculates the reactive power of the power system based on the detection values detected by the voltage detection sensor and the current detection sensor. However, since the operation is performed to compensate for the reactive power of the power system based on the calculated value, it is possible to compensate for the reactive power without providing a current detection sensor directly on the distribution line. The configuration of the power compensator is simplified, and the installation work is also facilitated.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a book diagram showing a schematic configuration of a system voltage stabilizing device provided with a reactive power compensating device of the present invention, and FIG. 2 is a schematic diagram showing an example in which the system voltage stabilizing device is installed on a pole. It is. As shown in FIG. 1, a system voltage stabilizing device including a reactive power compensating device of the present invention connects a movable contact of a switch 30 in parallel with a power system L, and applies a reactive power to a fixed contact of the switch 30. Compensation device 10
And the switch 30 is connected to a monitoring slave station 40.
Are connected.

The reactive power compensator 10 includes a main circuit 11
And a control circuit 13 for giving a control signal to the main circuit unit 11 and determining whether or not the main circuit unit 11 is out of order. The main circuit section 11 receives a signal from the control circuit 13 and operates under the control of the power system L so as to have an L (inductance) or C (conductance) component.

The control circuit 13 is composed of a well-known microcomputer. The control circuit 13 includes a switch 30 and a voltage of the power system L detected by a PT (instrument transformer) 32 and a CT (current transformer) 33. Calculates the reactive power of the power system L based on the detected current of the power system L, and sends a control signal for causing the main circuit unit 11 to perform a circuit operation based on the calculated value. Here, when the calculated reactive power is in the leading phase, the control circuit 13 controls each circuit of the main circuit unit 11 so that the main circuit unit 11 acts as L (inductance) when viewed from the power system L. When the calculated reactive power has a delayed phase, a control signal for controlling each circuit of the main circuit unit 11 is transmitted so that the main circuit unit 11 acts as C (conductance) when viewed from the power system L.

The control circuit 13 has a PT (transformer for an instrument).
The voltage of the power system L detected at 32 is compared with a set reference voltage, and when the voltage of the power system L is high, the main circuit unit 11 acts as L (inductance) when viewed from the power system L. A control signal for controlling each circuit of the main circuit unit 11 is transmitted, and when the voltage of the power system L is low, the main circuit unit 1
A control signal for controlling each circuit of the main circuit unit 11 may be transmitted so that 1 acts as C (conductance) when viewed from the power system L.

The switch 30 has a contact 31 consisting of a movable contact connected to the power system L and a fixed contact connected to the main circuit section 11 of the reactive power compensator 10, and a PT (PT) for detecting the voltage of the power system L. Voltage transformer 32), CT (current transformer) 33 for detecting the current of the power system L, and the reactive power compensator 1
ZCT that detects zero-phase current on the 0 side and outputs a ground fault signal
(Zero-phase current transformer) 34 and a trip coil 35 which is excited by a trip signal from the SOG relay 41 described later and releases the lock of the contact 31.

The monitoring slave station 40 sends a trip signal to a trip coil 35 provided in the switch 30 based on a detection signal (ground fault signal) of a ZCT (zero-phase current transformer) 34 provided in the switch 30. Power is supplied from the SOG relay 41 to be transmitted and the pole transformer (see FIG. 2) Tr, and the switch 3
The communication unit 42 monitors the state of the reactive power compensator 10 by monitoring the state of 0, and leaves the monitored state to the master station (not shown).

An example in which the system voltage stabilizing device configured as described above is installed in a power system will be described. As shown in FIG. 2, first, a gantry F is installed between two power poles P1 and P2, The reactive power compensator 10 is arranged on the gantry F. In addition, a pole transformer T is provided above one pole P1.
In addition to installing r, the monitoring slave station 40 is installed underneath, and the switch 30 is installed on the other telephone pole P2.

Thereafter, the input terminals 30a of the switch 30,
30b, the power system L is connected, and the output terminal 30c of the switch 30 and the input terminal 1 of the reactive power compensator 10 are connected.
0a. On the other hand, the pole transformer Tr is connected to the monitoring slave station 40, the communication unit 42 of the monitoring slave station 40 is connected to the communication line with the master station, and the SOG relay 41 and the switch 30 of the monitoring slave station 40 are provided. ZCT (zero-phase current transformer) 34. Further, a PT (current transformer) 32 and a CT (current transformer) 33 provided in the switch 30 and the control circuit 13 of the reactive power compensator 10 are connected to the power system L of the system voltage stabilizer. Installation is completed.

Next, the operation of the system voltage stabilizer of the present invention installed as described above will be described. First, when the contact 31 of the switch 30 is turned on, the switch 30 is turned on.
Of the power system L through the input side terminal 30a and the output side terminal 30c of the reactive power compensator 10.
flows into a. Then, the current of the power system L flows into the main circuit section 11 of the reactive power compensator 10. However, for example, when it is desired to control the reactive power of the power system L to be 0, the control circuit 13 uses the PT (instrument transformer) 32 and the CT (current transformer) provided in the switch 30.
As a result of calculating the reactive power based on the voltage and the current detected by 33, if neither the lagging phase nor the leading phase occurs in the power system L, the control circuit 13 does not send a control signal to the main circuit unit 11, The main circuit section 11 does not operate.

Here, when an overload condition occurs at the load end of the power system L and a lag phase occurs in the power system L, the control circuit 13 sends a control signal to the main circuit unit 11. In the operating state, the operation is performed so as to eliminate the delay phase. On the other hand, when the advance phase occurs in the power system L, the control circuit 13 sends a control signal to the main circuit section 11, so that the main circuit section 11 is in an operating state and operates to eliminate the advance phase. Become.

In such a state, if a ground fault occurs on the reactive power compensator 10 side, a ZCT (zero-phase current transformer) 34 provided in the switch 30 detects this ground fault and detects Outputs a ground fault signal. Then, the SOG relay 41 provided in the switch 30 sends a trip signal to the trip coil 35 based on the ground fault signal. As a result, the trip coil 35 provided in the switch 30 is excited, and the movable contact of the contact 31 is unlocked.
1 is released, so that a ground fault current can be prevented from flowing into the power system L.

Since the SOG relay 41 sends a trip signal to the trip coil 35 and the SOG relay 41 sends a signal corresponding to the trip signal to the communication unit 42, the communication unit 42 is connected to a master station (not shown). , This master station is provided, for example, at each sales office of a power company)
A signal indicating that a ground fault has occurred.

Although not shown, the switch 30 is provided with a well-known OC relay (cut-off relay).
When a short circuit accident occurs on the reactive power compensator 10 side,
Since the OC relay causes the contact 31 to perform an energy-storing trip operation, after a short-circuit accident has occurred, if a predetermined time has elapsed after the power failure of the substation and the short-circuit current has disappeared, the trip coil 35 is excited. Then, the movable contact of the contact 31 is unlocked and the contact 31 is opened.

As described above, in this embodiment,
The switch 30 includes a ZCT (zero-phase current transformer) 34 that detects a ground fault on the reactive power compensator 10 and outputs a ground fault signal, and a trip coil 35 that opens the contact 31 of the switch 30. Therefore, when a ground fault occurs, the power system L can be protected.

Modified Example Next, a modified example of the above-described embodiment will be described with reference to FIG. FIG. 3 is a book diagram showing a schematic configuration of a system voltage stabilizing device including the reactive power compensating device of the present modification. In FIG. 3, the same reference numerals as those in FIG. 1 denote the same names and the same functions, and therefore only different points from FIG. 1 will be described.

As shown in FIG. 3, the system voltage stabilizing device including the reactive power compensating device according to the present modification includes a reactive ground compensating device 10 provided with a simulated ground fault signal generator 14 and a simulated ground fault signal generating device. The simulated ground fault signal sent from the fault signal generator 14 is sent to a ZCT (zero-phase current transformer) 34 of the switch 30.

The control circuit 13 determines the temperature state, voltage state or current state of the main circuit section 11 based on a temperature sensor, voltage sensor or current sensor (not shown) provided in the main circuit section 11. When the value is determined to be abnormal and the reactive power compensator 10 is determined to be disconnected from the power system L, an abnormal signal is transmitted to the simulated ground fault signal generator 14. The control circuit 13 further controls the reactive power compensator 10
An open switch signal is sent to the simulated ground fault signal generation unit 14 based on an open signal from an open switch provided on an operation panel (not shown), and the simulated ground fault signal generation unit 14 is set to an operating state.

When the simulated ground fault signal generator 14 is provided as described above, the reactive power compensator 10 operates as follows. That is, first, when the contact 31 of the switch 30 is turned on, the power system L through the input terminal 30a and the output terminal 30c of the switch 30 is turned on.
Flows into the input terminal 10a of the reactive power compensator 10. Then, the current of the power system L flows into the main circuit section 11 of the reactive power compensator 10.

Here, when an abnormality occurs in an element of the main circuit section 11 of the reactive power compensator 10, the control circuit 13 determines whether or not there is a failure based on signals from each sensor of the main circuit section 11, If it is determined that a fault has occurred, a control signal is sent to the simulated ground fault signal generator 14. Then, the simulated ground fault signal generator 14 sends a simulated ground fault signal (for example, a current of 1.0 A) to the ZCT (zero-phase current transformer) 34,
(Zero-phase current transformer) 34 detects a ground fault and
A ground fault signal is sent to the SOG relay 41 of 0.

Then, the SOG relay 41 sends a trip signal to the trip coil 35 of the switch 30. Therefore, the trip coil 35 is excited based on the trip signal, and the movable contact of the contact 31 of the switch 30 is turned on. The lock is released and the contact 31 is opened. As a result, even when an abnormality occurs inside the reactive power compensator 10, the reactive power compensator 10 is not connected to the power system L, so that it is possible to prevent the power system L from being adversely affected. .

Further, when an operator presses an open switch provided on an operation panel (not shown) to disconnect the reactive power compensator 10 from the power system L, the control circuit 13 simulates based on the open signal of the open switch. An open switch signal is sent to the ground fault signal generator 14. Then, the simulated ground fault signal generation unit 14 is activated, and the ZCT (zero-phase current transformer) 34
The ZCT (zero-phase current transformer) 34 detects a ground fault and sends the ground fault signal to the SOG relay 41 of the monitoring station 40. Send out. Then, the SOG relay 41 sends a trip signal to the trip coil 35 of the switch 30. Therefore, the trip coil 35 is excited based on the trip signal, and unlocks the movable contact of the contact 31 of the switch 30. Then, the contact 31 is opened.

As described above, in the present invention, the ZCT (zero-phase zero phase detection) that detects a ground fault based on the generation of a weak current in the switch 30 due to a fault such as a ground fault on the reactive power compensator 10 side. Current transformer) 34 and contact 31 of switch 30
And a trip coil 35 for opening the coil. Therefore, when the ZCT (zero-phase current transformer) 34 detects a ground fault and outputs a ground fault signal, the SOG
The relay 41 detects the trip coil 3 based on the ground fault signal.
5, the trip coil 35 is energized and acts to release the lock of the contact 31, so that the power system L is protected from a ground fault on the reactive power compensator 10 side. Will be able to do it.

[Brief description of the drawings]

FIG. 1 is a book diagram showing a schematic configuration of an embodiment of a system voltage stabilizing device including a reactive power compensating device of the present invention.

FIG. 2 is a schematic diagram showing an example in which the system voltage stabilizer of FIG. 1 is installed on a pole.

FIG. 3 is a diagram showing a modification of the reactive power compensator of FIG. 1;

FIG. 4 is a diagram showing a schematic configuration of a system voltage stabilizing device including a conventional reactive power compensating device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Reactive power compensator, 11 ... Main circuit part, 13 ... Control circuit, 14 ... Simulated ground fault signal generation part, 30 ... Switch, 31
... Contact, 32 ... PT (instrument transformer), 33 ... CT (current transformer), 34 ... ZCT (zero-phase current transformer), 35 ... trip coil, 40 ... monitoring station, 41 ... SOG relay, 42 …
Communication unit, L ... power system

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Seiki Ito 2-56, Suda-cho, Mizuho-ku, Nagoya-shi, Aichi Japan Insulator Co., Ltd. (56) References JP-A-3-226221 (JP, A) JP-A Sho 55-133620 (JP, A) JP-A-8-211951 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02H 3/34 H02H 3/347 H02J 3/18 H02J 13 / 00

Claims (2)

(57) [Claims] 1. When the system voltage of the power system fluctuates, the same power
Equipped with a reactive power compensator that stabilizes voltage fluctuations in the system
System voltage stabilizing device, wherein the reactive power compensator is connected to the power system via a switch.
Connect and monitor the status of the power system to
A monitoring slave station that notifies the monitoring status by communication with the master station
Connected to the switch, the reactive power compensator compensates the reactive power of the power system
A main circuit unit for controlling and operating the main circuit unit.
A control circuit for detecting an abnormality in the main circuit section;
Generates a simulated ground fault signal when an abnormality is detected in the main circuit
A simulated ground-fault signal generator, and a simulated ground-fault signal generator in the switch.
A zero-phase current transformer that outputs a ground fault signal in response to a ground fault signal;
A contact connecting the reactive power compensator to the power system
Provided trip coil for opening and closing, and outputs a ground fault signal when said zero-phase current transformer for detecting the simulated ground No. fault signal sent from said simulated grounding signal generator, this
The monitoring slave station sends a trip signal before Symbol trip coil based on the ground fault signal, to characterized in that the trip coil is so as to opening operation of the contacts of the switch is excited by the trip signal system voltage stabilizer having a reactive power compensator that. 2. The switch comprises a voltage detection sensor and a current detection sensor, and the reactive power compensator reduces the reactive power of the power system based on detection values detected by the voltage detection sensor and the current detection sensor. The system voltage stabilizing device comprising the reactive power compensating device according to claim 1 , wherein the system voltage is calculated and the reactive power of the power system is compensated based on the calculated value.