KR100940175B1 - Voltage control device for protecting surge arrestor - Google Patents

Abstract

PURPOSE: A voltage controller for protecting a lightning arrester is provided to prevent damage to the lightning arrester due to frequent TSC(Thyristor Switched Capacitor) switching operations of an SVC(Static Var Compensator) by controlling an operation of the SVC according to the temperature of the lightning arrester. CONSTITUTION: A temperature sensor(20) converts the temperature of a lightning arrester into a digital signal. An operator(30) includes a transformer, a first memory, and a comparator. The transformer calculates a storage energy value from the digital signal. The first memory stores the energy capability of the lightning arrester. The comparator compares the energy capability with the storage energy value. An auxiliary controller(50) controls the on/off status of the SVC of a main controller(40) according to the comparison result of the operator.

Description

Voltage control device for lightning arrester protection {VOLTAGE CONTROL DEVICE FOR PROTECTING SURGE ARRESTOR}

TECHNICAL FIELD The present invention relates to the field of power device protection technology, and more particularly, to a voltage control device for protecting an arrester attached to a thyristor switched capacitor (TSC) included in a static var compensator (SVC).

FIG. 1A is a schematic configuration diagram of an SVC system according to the prior art, FIG. 1B is a schematic configuration diagram of a TSC circuit and an arrester of the SVC system according to the prior art, and FIG. 1C shows a voltage- reactive current compensation control characteristic of an SVC. It is a graph. 1A to 1C, a conventional SVC is composed of a Thyristor Switched Capacitor (TSC) and a Thyristor Controlled Reactor (TCR), and performs an operation with a voltage- reactive current compensation control characteristic as shown in FIG. 1C. In the case of TCR, continuous firing angle control is performed through the thyristor power device, but in the case of TSC, continuous firing angle control is impossible due to the characteristics of the capacitor bank, and thus only the switch on / off control is performed.

FIG. 2 is a diagram illustrating a bypass current of an arrester according to the voltage exceeding the voltage protection level of the arrester when the TSC is off and the amount of energy accordingly. As shown in FIG. 2, the switching of the TSC puts a lot of stress on the thyristor power device. Therefore, in the case of the TSC, the thyristor power device stage can be bypassed as shown in FIG. 1B for the protection of the thyristor power device. The arrester is installed.

The role of the arrester is not only to protect the thyristor power device of the TSC in case of disturbance from the external system, but also to protect the thyristor power device from the overvoltage generated during the switching operation of the general TSC, especially during the off operation.

To this end, as illustrated in FIG. 1B, an arrester having an appropriate protection level and sufficient energy content is selected and installed. The reason for installing an arrester having an appropriate level of protection and a sufficient amount of energy is to prevent damage to the arrester itself while efficiently protecting the thyristor power device.

However, unlike the use of lightning arresters in general transmission substations, SVC sometimes performs very frequently TSC on / off in a short time to perform voltage control. In this case, if the arrester increases in stress (energy) accumulation and is not given enough time to dissipate it as heat, it is likely that the energy content is exceeded and the arrester may be damaged.

On the other hand, in the existing SVC, there is no method for protecting the arrester, and therefore, a means capable of preventing the damage of the arrester due to frequent switching is needed.

The present invention has been devised to solve the above problems of the prior art, and an aspect of the present invention is to install a temperature sensor in the vicinity of the arrester, and compare the energy value of the arrester with the energy value measured from the temperature sensor and compare the energy content of the arrester. According to the result, a voltage arrestor protection voltage control device capable of controlling the SVC by assisting the main controller of the SVC is provided.

According to an aspect of the present invention, there is provided a lightning arrester protection voltage control device added to an SVC in support of a main controller, the voltage control device comprising: a temperature sensor for measuring and outputting a temperature generated by the arrester; A calculator for converting the measured temperature into an energy value and comparing it with an energy content value of the arrester; And an auxiliary controller including an output control section and activating the output control section in response to a comparison value from the operator to control the SVC from operating during the output control section.

The calculator converts a temperature measured by the temperature sensor into an energy value, a first memory for storing an energy content value of the arrester, and an energy value from the converter and an energy content stored in the first memory. It may include a comparator comparing the values and outputting a first or second value.

The auxiliary controller may include a second memory for setting and storing the output control section, an activator for activating or deactivating the output control section according to an output value from the operator, and a first controller so that the main controller is not operated during the output control section. It may include a command signal generator for outputting a second value.

As described above, the arrester protection voltage control device of the present invention can measure the temperature change of the arrester and control the operation of the SVC based on the measured value, thus preventing the lightning arrester due to frequent TSC switching operation of the SVC. Can be.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings, wherein like reference numerals refer to like elements. The terms or words used in the specification and claims are not to be construed as being limited to conventional or dictionary meanings, but should be construed as meanings and concepts corresponding to the technical matters of the present invention.

The embodiments described in the specification and the configuration shown in the drawings are preferred embodiments of the present invention, and do not represent all of the technical idea of the present invention, various equivalents and modifications that can be substituted for them at the time of the present application are There may be.

Prior to explaining the embodiment of the present invention with reference to the accompanying drawings will be described the basic concept of the present invention.

As described above, the control of the grid voltage is performed by combining the TSC switching control and the TCR firing angle control in the SVC. The amount of energy applied to the arrester according to the TSC operation of the SVC may be expressed by Equation 1 below.

Where Va is the voltage across the arrester, Ia is the current through the arrester, and td is the current impulse time applied to the arrester.

According to the circuit theory, energy is represented as in Equation 2 below, but in the case of the lightning arrester, since the voltage-current characteristic as shown in FIG. 3 has nonlinearity, it can be represented by Equation 3 below.

As in Equation 3, the energy applied to the arrester may be represented by Joule heat (J).

Therefore, the present invention attaches a temperature sensor to the arrester, measures the thermal energy generated by the arrester through the temperature sensor, and suspends the operation control of the SVC within the dead band of the output of the SVC when the measured thermal energy is larger than the energy content of the designed arrester. Let's do it. Therefore, when the operation control of the SVC is paused, the switching operation of the TSC is also stopped, and thus the energy applied to the arrester is also stopped, and thus Joule heat generated by the arrester can be reduced.

The present invention has been devised based on the above concept.

Hereinafter, a lightning arrester protection voltage control device according to an embodiment of the present invention will be described with reference to FIGS. 4, 5A, and 5B.

Figure 4 is a schematic view showing a state in which the lightning arrester protection voltage control device according to an embodiment of the present invention is attached to the SVC system, Figure 5a is a block diagram showing a voltage control device of the SVC system according to the prior art 5b is a block diagram further including a lightning arrester protection voltage control device according to an embodiment of the present invention.

4 to 5B, the voltage control device for protecting the lightning arrester 12 according to the exemplary embodiment of the present invention is connected to the SVC so as to be switchable to control the SVC by assisting the main controller 40 and the temperature sensor 20. ), An operator 30, and an auxiliary controller 50.

The temperature sensor 20 is installed near the arrester 12 to detect joule heat generated by the arrester 12 and to measure the temperature. The temperature sensor 20 may also convert the measured temperature into a digital data value and supply it. To this end, the temperature sensor 20 may include (not shown) a digital data value generator for outputting the digital data value separately or in the inside thereof.

The calculator 30 compares the temperature value measured and output from the temperature sensor 20 with the energy content of the arrester 12 already stored in the (not shown) memory. If the comparison result is greater than the set margin may generate a command signal to operate the auxiliary controller 50.

The calculator 30 may include (not shown) a memory or the like for storing the energy content of the arrester 12 separately or therein. The calculator 30 may use a general type comparator implemented with OP-Amp to compare the measured temperature value and energy content with each other, but is not particularly limited thereto. A more detailed description of the calculator 30 will be described later with reference to FIG. 6.

The auxiliary controller 50 serves to assist the main controller 40 for controlling the operation of the SVC. First, the main controller 40 serves to turn on / off the SVC operation. Operation control of the SVC by the master controller 40 may be implemented manually by an administrator or automatically through a computer control device when a problem such as a defect or damage occurs in the SVC.

The auxiliary controller 50 according to the present invention assists and controls the main controller 40 for controlling the operation of the SVC. More specifically, when the output control section (Dead Band) is set in the auxiliary controller 50 and a command signal for performing an operation from the operator 30 is input, the auxiliary controller 50 receives the dead band set therein. It activates and generates a command signal to the main controller 40 so that the main controller 40 of the SVC does not operate during this dead band.

The main controller 40 receiving the command signal from the auxiliary controller 50 does not perform the SVC output control in the dead band section in response thereto. At this time, the value of the dead band width may vary depending on the voltage of the system.

If the measured thermal energy of the arrester 12 is returned to a stable state having a margin higher than or equal to the energy content of the arrester 12, the auxiliary controller 50 cancels activation of the dead band so that the main controller 40 of the SVC can be cancelled. Can be restored to perform the original operation control.

A more detailed description of the auxiliary controller 50 will be described later with reference to FIGS. 7A and 7B.

6 is a block diagram showing an internal structure of a calculator included in the arrester protection voltage control apparatus according to an embodiment of the present invention.

Referring to FIG. 6, the calculator 30 included in the lightning arrester protection voltage control device according to an embodiment of the present disclosure may convert a temperature value measured by the temperature sensor 20 into an energy value A −. From the energy value A and the memory 32 from the energy value conversion unit 31, the memory 32 for storing the energy content value B of the arrester 12, and the temperature-energy value conversion unit 31; It may include a comparator 33 for comparing the energy content value (B) of each other.

The temperature-energy value converting unit 31 may be implemented using a general type calculator. The memory 32 may be used regardless of its form such as cache, ROM, RAM, EPROM, and the like.

Or it may be implemented in the form of a buffer for temporarily storing the user input by the (not shown) input unit, the present invention is not particularly limited.

The comparator 33 compares the energy value A and the energy content value B with each other and if the energy value A is greater than the energy content value B, as a result, for example, a value of 1 can be outputted. If (A) is equal to or less than the energy content value B, a value of 0 can be output.

An output value of 1 from the comparator 33 means that the energy value A of the arrester 12 is greater than the energy content value B of the arrester 12, which means that the arrester 12 is overheated and thus protects. Indicates that there is a need.

An output value of 0 from the comparator 33 means that the energy value A of the arrester 12 is equal to or less than the energy content value B of the arrester 12, which means that the arrester 12 is now stable. It indicates that you are operating in a state and therefore can continue to perform actions.

The output values 1 and 0 may be transmitted to the auxiliary controller 50 to act as the command signal for controlling the operation of the auxiliary controller 50.

FIG. 7A is a block diagram illustrating an internal structure of an auxiliary controller included in an arrester protection voltage control device according to an embodiment of the present invention, and FIG. 7B is a graph showing a dead band set in the auxiliary controller.

The auxiliary controller 50 included in the lightning arrester protection voltage control device according to an embodiment of the present invention performs the operation from the dead band storage memory 51 and the calculator 30 to set and store the dead band. When the command signal is input, that is, the output value from the operator 30 in FIG. 5 is 1, the activator 52 for activating the dead band set and stored in the memory 51, and the main controller of the SVC during this dead band. The command signal generator 53 generates a command signal so that the 40 does not operate, and transmits a value of 0 to the main controller 40, for example, of 1 and 0 digital signals.

The main controller 40 does not perform SVC output control in the dead band section in response to the command signal, for example, the value of zero. At this time, the value of the dead band width may vary depending on the voltage of the system.

If the measured thermal energy of the arrester 12 is returned to a stable state with a margin higher than or equal to the energy content of the arrester 12, the activator 52 in the auxiliary controller 50 deactivates the dead band and generates a command signal. The unit 53 generates, for example, a value of 1 and transmits the master controller 40 to the master controller 40 so that the master controller 40 operates.

The master controller 40 may be restored to its original operating state in response.

The technical spirit of the present invention has been described above with reference to the accompanying drawings, but this is by way of example only and not by way of limitation to the present invention. In addition, it is obvious that any person skilled in the art can make various modifications and imitations without departing from the scope of the technical idea of the present invention.

1A is a schematic structural diagram of an SVC system according to the prior art;

1B is a schematic configuration diagram of a TSC circuit and an arrester of an SVC system according to the prior art;

1C is a graph showing voltage- reactive current compensation control characteristics of an SVC;

FIG. 2 is a diagram illustrating a bypass current of an arrester according to a voltage exceeding a voltage protection level of the arrester when the TSC is turned off, and a corresponding amount of energy; FIG.

3 is a graph showing current and voltage characteristics applied to an arrester;

4 is a view schematically showing how a lightning arrester protection voltage control device according to an embodiment of the present invention is attached to an SVC system;

5A is a block diagram showing an SVC system voltage control apparatus according to the prior art;

Figure 5b is a block diagram further comprising a voltage arrester protection voltage control device according to an embodiment of the present invention;

6 is a block diagram showing the internal structure of a calculator included in the arrester protection voltage control apparatus according to an embodiment of the present invention;

Figure 7a is a block diagram showing the internal structure of the auxiliary controller included in the voltage arrester protection voltage control apparatus according to an embodiment of the present invention; And

7B is a graph illustrating dead bands set in an auxiliary controller.

Claims (3)

An SVC system including an SVC including a TSC, a main controller for controlling an on / off operation of the SVC, and an arrester for protecting the TSC, A temperature sensor measuring a temperature generated by the arrester and converting the temperature into a digital signal; A calculator for calculating a stored energy value from the digital signal converted by the temperature sensor and comparing it with an energy content value of the arrester; And And an auxiliary controller configured to auxiliary control the SVC on / off operation of the main controller based on a comparison result in the calculator. The method of claim 1, wherein the calculator, A converting unit calculating a stored energy value from the temperature measured by the temperature sensor; A first memory for storing an energy content value of the arrester; And comparing the accumulated energy value calculated by the converter with the energy content value stored in the first memory, and outputting a first value when the accumulated energy value is greater than the energy content value, and outputting a first value when the accumulated energy value is less than or equal to the energy content value. A comparator for outputting a value of 2; The auxiliary controller, A second memory for setting and storing an output control section; An activator for deactivating an output control section stored in the second memory when the output value from the calculator is the first value, and activating the output control section when the output value is the second value; And a command signal generator for transmitting the second value to the main controller so that the main controller does not operate while the output control section is activated. delete

Images