KR20230053335A - Multifunctional phase measuring device with fault distance detection - Google Patents

Abstract

The present invention relates to a multi-functional phase measuring device, comprising: a first sensor unit and a second sensor unit which sense and sample the voltage and current input through a first terminal and a second terminal, respectively; a fault distance detection unit which includes a phase synchronization phasor and synchronizes the sampling data of the first sensor unit and the second sensor unit to a reference time to generate data for calculating a fault distance; a merging unit which converts the sampling data of the first sensor unit and the second sensor unit into digital data; and an Ethernet communication unit which transmits the digital data of the merging unit to a digital substation system, wherein the first terminal, the second terminal, the first sensor unit, the second sensor unit, the fault distance detection unit, the merging unit, and the Ethernet communication unit are located on the same board, and the data of the fault distance detection unit can be shared through a bus. According to the present invention, stability can be improved by minimizing the use of an open-type CT circuit.

Description

Multifunctional phase measuring device with fault distance detection

The present invention relates to a phase measuring device, and more particularly, to a phase measuring device capable of detecting a fault distance of a transmission line using a phase-locked phasor.

Recently, the development of large-scale new and renewable power sources has been made due to the government's promotion of new and renewable energy policies. Electric power produced from large-scale renewable power sources is connected to the existing transmission/distribution network, but there are cases in which system stability and power quality are adversely affected.

New 154kV substations are being operated unmanned by applying automation technology, so new digital-based devices for intelligent power facility monitoring and system protection are in demand.

As KEPCO recently announced digital convergence and is drawing up a roadmap for future power facility operation, it is necessary to develop technologies and products in preparation for the new power protection device market. The development of a multifunctional IED with a digital sensing merging transmission function for measurement-based grid fault location calculation and substation automation is required.

The grid protection function of the substation automation system needs to measure voltage and current. The analog value is measured through the instrument transformer and then fed to the protection device and processed by the protection algorithm. Conventional instrument transformers use parallel copper wires to connect directly to the protection device. This solution is proven, but requires a lot of wiring work, has physical limitations (accuracy, chroma), and has an open CT circuit risk.

This innovative solution involves placing the merging unit close to the transformer. The merger records and digitizes the transformer's measurements, then sends the sampled measured values (SMV) via fiber optic Ethernet via a data stream to one or more protection devices.

Protection relays no longer operate with analog values, but directly use the digital values of the sampled measured value data stream. The merging unit is an interoperable interface between primary and secondary equipment for process bus solutions compliant with IEC 61869 and IEC 61850-9-2. Measurements from conventional and non-traditional transformers are converted into standardized Ethernet-based telegrams (SMV).

The IEC 61850 standard is more than just an Ethernet-based substation automation protocol.

The standard comprehensively defines engineering processes, data and service models, conformance testing and overall communication within a substation. Today, IEC 61850 is firmly established in the field of substation automation, and the recently released Edition 2 makes its advantages available in other areas of the energy supply business.

Currently, products for digital substations are distributed in domestic and overseas markets by importing them in the form of complex functions such as Protection Relay+PMU, Protection Relay+Merging Unit (hereafter MU, IEC61850-based digital sensing and transmission device). Therefore, it is judged that technological and price competitiveness will increase if PMU + MU products are developed and supplied to the market, which is the technical goal of this project.

In Korea, protection relay-based PMU or fault recorder-based PMU products are in demand in the market, but in the Southeast Asian market, where power transmission and distribution systems are unstable, demand for PMU + Fault Locator (Power Grid Fault Locator, hereinafter F/L) products is the highest

This phenomenon appears to be due to the high demand for the line because the line length is long and transmission and distribution power facilities are in poor operating condition, and line breakdowns occur frequently.

PMU, F/L, and MU are participating in technology development by both large companies and SMEs, and as global companies (Schneider, SIEMENS, ABB, GE, SEL) are expected to have their own technologies, PMU, It is expected that F/L and MU will be integrated to enter the market.

In the domestic power grid, technologies in various fields such as power facility monitoring technology, facility prevention diagnosis technology, online real-time system information acquisition technology, as well as system protection technology are being researched and developed for stable power supply.

The existing analog mechanical relays were applied to the protection switchgear for each facility in the system, but most recently digital protection relays are applied.

In particular, IEC 61850, a standard for digital substations, is a standard preferred by most utilities, so it is judged that most transmission and transformation equipment will be under the influence of this standard in the near future. It is expected that the sensor field (VT, CT), which is an existing analog area, will be converted to a digital sampling method.

As a technology for detecting the location of a transmission line failure, Registration Patent No. 10-2121046 (registered on June 3, 2020, complex transmission line failure detection device) is known.

In the above registered patent, a configuration for collecting fault current from a plurality of sensors and detecting a fault location based on a phase change of the synchronized fault current is described.

That is, a method of providing PMU data measured by the phase measurement unit (PMU) of the current transformer sensor to a separate fault location detector and calculating a fault distance from the fault location detector is used.

This uses the phase angle change of the fault current and the occurrence time of the fault current. A sensor that detects the fault current and a configuration that determines the fault location using the data detected by the sensor are provided separately, so that each device can be maintained and repaired. It is not easy, and there is a problem that the cost increases.

In addition, the conventional technology uses an analog electrical signal and has a problem in that it cannot be applied to a digital substation.

In view of the above problems, an object of the present invention to be solved is to provide a PMU capable of calculating a fault distance required for monitoring a transmission line fault by itself using phase-synchronized phasor data calculated through a unique function of the PMU.

Another object of the present invention is to provide a PMU capable of digitally converting and transmitting an analog electrical signal required for operating a digital substation.

In order to solve the above technical problem, the multifunctional phase measurement device capable of detecting the distance to a fault of the present invention has a first sensor unit for sensing and sampling voltage and current input through a first terminal and a second terminal, respectively, and a second sensor unit for sampling. A sensor unit and a failure distance detection unit generating data for calculating a failure distance by synchronizing the sampling data of the first sensor unit and the second sensor unit with a reference time including a phase-synchronized phasor; A merging unit that converts the sampling data of the sensor unit into digital data, and an Ethernet communication unit that transmits the digital data of the merging unit to a digital substation system, including the first terminal, the second terminal, the first sensor unit, and the second sensor. The unit, the fault distance detection unit, the merging unit, and the Ethernet communication unit are located on the same board, and the data of the failure distance detection unit can be shared through a bus.

In an embodiment of the present invention, the failure distance detection unit includes a GPS module for receiving a GPS satellite signal and generating a measurement synchronization signal, a timer for outputting a timing signal of a certain period, and reliability according to whether or not the GPS satellite signal is reliable. When there is, a measurement synchronization signal of the GPS module is selected, and when there is no reliability, a timing signal of the timer is selected to generate a synchronization signal.

In an embodiment of the present invention, the fault distance detection unit includes an analog-to-digital conversion unit that converts the sampled data into digital data, and a phase-locked phasor that synchronizes the sampled data converted into digital data with the sync signal to detect a phase. and a bus driver for transmitting an output of the phase-locked pager through a bus.

In an embodiment of the present invention, the fault distance detection unit includes an analog-to-digital conversion unit that converts the sampled data into digital data, a phase-locked phasor that synchronizes the sampled data converted to digital data with the synchronization signal and detects a phase, , a fault distance calculation unit that detects a phase change point in the output of the phase-synchronized pager and calculates a fault distance, and a bus driver that transmits the calculation result of the fault distance calculator through a bus.

In an embodiment of the present invention, the merging unit may include an analog-to-digital converter that converts the sampling data into digital data, and a signal processor that converts the data of the analog-to-digital converter into data suitable for communication.

The present invention has the effect of reducing cable equipment and maintenance costs by providing a phase measuring device that combines various functions.

In addition, the present invention has an effect of improving stability by minimizing the use of an open type CT circuit.

In addition, the present invention provides a cut-off signal directly to a digital protection relay suitable for operating a digital substation, so that it can be applied to a digital substation and does not require the development and application of additional facilities, thereby reducing costs.

1 is a block diagram of a multi-function phase measuring device capable of detecting a fault distance according to a preferred embodiment of the present invention.
2 is a block configuration diagram of a failure distance detection unit.
3 is a block diagram of a merging unit.

In order to fully understand the configuration and effects of the present invention, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, and may be implemented in various forms and various changes may be applied. However, the description of the present embodiment is provided to complete the disclosure of the present invention, and to completely inform those skilled in the art of the scope of the invention to which the present invention belongs. In the accompanying drawings, the size of the components is enlarged from the actual size for convenience of description, and the ratio of each component may be exaggerated or reduced.

Terms such as 'first' and 'second' may be used to describe various elements, but the elements should not be limited by the above terms. The above terms may only be used for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a 'first element' may be named a 'second element', and similarly, a 'second element' may also be named a 'first element'. can Also, singular expressions include plural expressions unless the context clearly indicates otherwise. Terms used in the embodiments of the present invention may be interpreted as meanings commonly known to those skilled in the art unless otherwise defined.

Hereinafter, a multi-function phase measuring device capable of detecting a fault distance according to a preferred embodiment of the present invention will be described with reference to the drawings.

1 is a block diagram of a multi-function phase measuring device capable of detecting a fault distance according to a preferred embodiment of the present invention.

Referring to FIG. 1, the multifunctional phase measuring device 100 of the present invention includes a first terminal 130 and a second terminal 140 to which voltage and current at different positions of a transmission line are input, and the first terminal 130 ) And the first sensor unit 150 and the second sensor unit 160 that detect voltage and current values input through the second terminal 140 and perform high-speed sampling, and the first sensor unit 150 ) and the sampling data of the second sensor unit 160 and the failure distance detection unit 110 that detects the failure distance using GPS time synchronization, and the sampling of the first sensor unit 150 and the second sensor unit 160 A merging unit (MU) 120 converts data into digital signals and transmits them to the outside through the Ethernet communication unit 170.

Hereinafter, the configuration and operation of the present invention configured as described above will be described in more detail.

First, the first terminal 130 and the second terminal 140 are electrically connected to two arbitrary positions of the transmission line. The first terminal 130 may be connected to the input side of the transmission line, and the second terminal 140 may be connected to the output side of the transmission line, but the present invention is not limited thereto.

For example, a transmission line may be divided into a plurality of divided regions, and the present invention may be applied to each divided region.

The multifunctional phase measurement device 100 of the present invention is mounted on one card (board), and a set of these cards and a main board for data processing and display can be mounted on the same system.

That is, the present invention can make a merging unit for fault distance calculation and digital substation into a single system by communicating with a plurality of expandable cards through a data bus (BUS).

Voltage/current input through the first terminal 130 and the second terminal 140 are detected and sampled by the first sensor unit 150 and the second sensor unit 160, respectively.

The first sensor unit 150 and the second sensor unit 160 each include a plurality of voltage/current sensors, and samples detection values of the voltage/current sensors at high speed. This means that all channels are sampled at the same time, and more than 128 samples are sampled per cycle.

The sampled data is input to the fault distance detection unit 110 and the merging unit 120.

2 is a block configuration diagram of the failure distance detection unit 110.

The fault distance detection unit 110 includes a GPS module 111 that generates a measurement sync signal based on a GPS satellite signal, a timer 112 that generates a timing signal, and a rise of the measurement sync signal when the GPS signal is reliable. Alternatively, a microcontroller (MCU, 113) for detecting a time interval between measurement synchronization signals according to a falling edge and setting the cycle of the output signal of the timer 112 to the detected time interval when it is not reliable, and A phase-locked phasor 114 that synchronizes the output of the microcontroller and the sampling data to detect a phase change of the fault current, and a distance for calculating a fault distance through a phase measurement result of the phase-locked phasor 114 and a calculation algorithm. It includes a calculation unit 115 and a bus driver 116 outputting the calculation result of the distance calculation unit 115 through a bus.

In the above configuration, the GPS module 111 generates accurate measurement synchronization signals based on GPS satellite signals. The measurement synchronizing signal is for determining the exact time point of occurrence of the fault current.

Satellite signals received by the GPS module 111 may not be received due to various factors. It is assumed to have reliability when the satellite signal has a good reception state, and to have no reliability when the reception of the satellite signal is not good.

In the present invention, the timer 112 is used to accurately determine the time of occurrence of a fault current when there is no reliability in satellite signal reception. The timer 112 outputs a timing signal at regular intervals.

The MCU 113 selects the measurement synchronization signal of the GPS module 111 when the satellite signal has reliability, and selects the timing signal of the timer 112 as the measurement synchronization signal when the satellite signal does not have reliability, and synchronizes accordingly. output a signal

The phase-synchronized pager 114 synchronizes sampling data in synchronization with the synchronization signal of the MCU 113 and detects a phase change thereof. It is assumed that the sampling data at this time are converted into digital data through the analog-to-digital conversion unit 117.

That is, when there is no fault current, the phase is constant, and when a fault current occurs, the phase changes.

Thereafter, the distance calculation unit 115 calculates the fault distance using an algorithm that interprets the detection result of the phase-locked pager 114. An EMTP simulator can be used to calculate the failure distance.

The calculated fault distance is transmitted to other cards through the bus driver 116 and the bus.

In the drawings, the failure distance detection unit 110 has been illustrated and described as including the distance calculation unit 115, but the distance calculation unit 115 may be located on the main board.

That is, the fault distance detection unit 110 generates synchronized phase information using the phase synchronization pager 114, and outputs the synchronized phase information to the outside using the bus driver 116 to externally output the separated main board as another card. The failure distance can be calculated from .

As such, the present invention can improve reliability and reduce costs by generating a synchronization signal using the timer 112 together with the GPS module 111.

3 is a simplified block configuration diagram of the merging unit 120.

The merging unit 120 converts the analog-to-digital converter 121 that converts the sampling data of the first sensor unit 150 and the second sensor unit 160 into digital data, and the digital data of the analog-to-digital converter 121. It may include a signal processing unit 122 that processes suitable for Ethernet communication.

In addition, a memory may be included, but it is omitted for convenience of description.

The merging unit 120 converts the analog data sampled through the first sensor unit 150 and the second sensor unit 160 into digital signals and transmits them to the digital substation, thereby operating the protection relay of the digital substation when a fault current occurs. can be controlled.

That is, the present invention can be applied to a digital substation and can protect a power system from a fault current without using a separate sensor.

As described with reference to FIGS. 2 and 3, it has been described that the analog-to-digital converters 117 and 121 are used for the fault distance detection unit 110 and the merging unit 120, respectively, but by integrating them into one analog-to-digital converter It can be shared by the fault distance detection unit 110 and the merging unit 120.

Embodiments according to the present invention have been described above, but these are merely examples, and those skilled in the art will understand that various modifications and embodiments of equivalent scope are possible therefrom. Therefore, the true technical protection scope of the present invention should be defined by the following claims.

110: failure distance detection unit 111: GPS module
112: timer 113: MCU
114: phase synchronization phasor 115: distance calculator
116: bus driver 117: analog-to-digital converter
120: merging unit 121: analog to digital conversion unit
122: signal processing unit 130: first terminal
140: second terminal 150: first sensor unit
160: second sensor unit 170: Ethernet communication unit

Claims (5)

a first sensor unit and a second sensor unit that sense and sample the voltage and current input through the first terminal and the second terminal, respectively;
a failure distance detection unit generating data for calculating a failure distance by synchronizing the sampling data of the first sensor unit and the second sensor unit with a reference time, including a phase-synchronized pager;
a merging unit converting the sampling data of the first sensor unit and the second sensor unit into digital data; and
An Ethernet communication unit for transmitting digital data of the merging unit to a digital substation system,
The first terminal, the second terminal, the first sensor unit, the second sensor unit, the fault distance detection unit, the merging unit, and the Ethernet communication unit are located on the same board,
The multi-function phase measuring device, characterized in that the data of the fault distance detection unit is shared through a bus. According to claim 1,
The fault distance detection unit,
a GPS module for generating a measurement synchronization signal by receiving a GPS satellite signal;
a timer outputting a timing signal of a constant period; and
A multifunctional phase measurement device including a microcontroller for generating a synchronization signal by selecting the measurement synchronization signal of the GPS module when reliability is present and selecting the timing signal of the timer when reliability is unreliable, depending on whether or not the GPS satellite signal is reliable. . According to claim 2,
The fault distance detection unit,
an analog-to-digital converter converting the sampling data into digital data;
a phase synchronization phasor that synchronizes the sampling data converted into digital data with the synchronization signal to detect a phase; and
Multifunctional phase measuring device further comprising a bus driver for transmitting the output of the phase-locked pager through a bus. According to claim 2,
The fault distance detection unit,
an analog-to-digital converter converting the sampling data into digital data;
a phase synchronization phasor that synchronizes the sampling data converted into digital data with the synchronization signal to detect a phase;
a fault distance calculation unit for calculating a fault distance by detecting a phase change point in the output of the phase-synchronized phasor; and
Multifunctional phase measuring device further comprising a bus driver for transmitting the calculation result of the fault distance calculation unit through a bus. According to claim 1,
The merging unit,
an analog-to-digital converter converting the sampling data into digital data; and
A multi-function phase measurement device including a signal processing unit that converts the data of the analog-to-digital conversion unit into data suitable for communication.

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