KR20080043088A - A high power quality anti-islanding method using effective power variation - Google Patents
A high power quality anti-islanding method using effective power variation Download PDFInfo
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- KR20080043088A KR20080043088A KR1020060111675A KR20060111675A KR20080043088A KR 20080043088 A KR20080043088 A KR 20080043088A KR 1020060111675 A KR1020060111675 A KR 1020060111675A KR 20060111675 A KR20060111675 A KR 20060111675A KR 20080043088 A KR20080043088 A KR 20080043088A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/381—Dispersed generators
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
- H02J13/00006—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment
- H02J13/00007—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment using the power network as support for the transmission
- H02J13/00009—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment using the power network as support for the transmission using pulsed signals
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/388—Islanding, i.e. disconnection of local power supply from the network
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/70—Smart grids as climate change mitigation technology in the energy generation sector
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
- Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
- Y04S10/00—Systems supporting electrical power generation, transmission or distribution
- Y04S10/12—Monitoring or controlling equipment for energy generation units, e.g. distributed energy generation [DER] or load-side generation
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
- Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
- Y04S40/00—Systems for electrical power generation, transmission, distribution or end-user application management characterised by the use of communication or information technologies, or communication or information technology specific aspects supporting them
- Y04S40/12—Systems for electrical power generation, transmission, distribution or end-user application management characterised by the use of communication or information technologies, or communication or information technology specific aspects supporting them characterised by data transport means between the monitoring, controlling or managing units and monitored, controlled or operated electrical equipment
- Y04S40/121—Systems for electrical power generation, transmission, distribution or end-user application management characterised by the use of communication or information technologies, or communication or information technology specific aspects supporting them characterised by data transport means between the monitoring, controlling or managing units and monitored, controlled or operated electrical equipment using the power network as support for the transmission
Abstract
Description
도 1 은 본 발명의 일 실시 예에 따른 단독운전현상을 검출하기 위한 플로우차트.1 is a flowchart for detecting a single operation phenomenon according to an embodiment of the present invention.
도 2 는 본 발명의 일 실시 예에 따른 인버터의 출력전류의 변동을 나타내는 플로우차트.2 is a flowchart illustrating a variation of an output current of an inverter according to an embodiment of the present invention.
도 3 은 본 발명의 일 실시 예에 따른 단독운전현상을 검출하기 위한 인버터의 출력전류와 출력전압의 그래프.3 is a graph of an output current and an output voltage of an inverter for detecting a single operation phenomenon according to an embodiment of the present invention.
도 4 는 본 발명의 일 실시 예에 따른 과주파수 계전기와 저주파수 계전기를 사용한 단독운전 검출을 나타낸 그래프.Figure 4 is a graph showing the detection of single operation using the over-frequency relay and low-frequency relay according to an embodiment of the present invention.
<도면의 주요부분에 대한 부호의 설명> <Description of the symbols for the main parts of the drawings>
I(RMS) : 실효치 전류 V(RMS) : 실효치 전압I (RMS): RMS current V (RMS): RMS voltage
I : 출력전류 △V(RMS) : 전압 변동분I: Output Current △ V (RMS): Voltage Variation
C : 주기 K : 전류 변화량C: Period K: Current variation
N : 지정치 Freg : 출력전압 주파수N: Specified value Freg: Output voltage frequency
OFR : 과주파수 계전기 UFR : 저주파수 계전기OFR: Overfrequency Relay UFR: Low Frequency Relay
T1 : 단독운전 발생시점 T2 : AFD 투입시점T1: When single operation occurs T2: When AFD is input
T3 : 단독운전 검출시점T3: Time to detect single operation
본 발명은 분산전원의 단독운전현상을 방지하기 위하여, 1차적으로 인버터의 출력전류의 크기를 한번은 지정치의 k% 증가시키고, 다음 한번은 지정치의 k%로 감소시키며, 마지막으로 일정기간 동안은 지정치의 전류크기를 가지도록 하여 주기적으로 동작시켜서 단독운전현상을 검출하고, 2차적으로 주파수 변동 방식(Active Frequecny Drift;AFD)을 사용하여 단독운전현상을 검출하는 유효전력 변동방식을 이용한 높은 전력품질의 단독운전 검출 방법에 관한 것이다.The present invention primarily increases the output current of the inverter once k% of the specified value, and then decreases it to the k% of the specified value in order to prevent the independent operation of the distributed power supply. High power using active power fluctuation method that detects single operation phenomenon by periodically operating by having current value of specified value and secondarily detects independent operation phenomenon by using frequency change method (Active Frequecny Drift (AFD)) It relates to a single operation detection method of quality.
현대 전력계통에는 분산전원이라는 이름으로 태양광발전, 풍력발전, 그리고 연료전지 발전 등의 새로운 발전원들이 상용계통에 연계되어 차세대 에너지원으로 각광을 받고 있다. In the modern power system, new generation sources such as photovoltaic, wind power, and fuel cell power generation are being spotlighted as next generation energy sources in the name of distributed power generation.
그러나, 분산전원의 발전량이 점차 증대됨에 따라, 기존의 전력계통의 안정성과 전력품질에 영향을 끼치는 문제점이 있다.However, as the amount of generation of distributed power supplies is gradually increased, there is a problem that affects the stability and power quality of the existing power system.
이 중에서, 분산전원과 연계된 상용계통이 정전이 발생하였음에도 불구하고 이를 감지하지 못한 분산전원이 계속해서 독립적으로 발전을 하는 단독운전현상이 발생하는데, 이러한 분산전원의 단독운전현상은 계통유지 요원의 감전사나 혹은 상용계통 재투입시 인접 전력계통 설비의 파괴 등의 문제점을 발생시킨다.Among them, a stand-alone operation occurs in which a distributed power source that does not detect a power generation system continuously operates independently, even though a commercial system connected to a distributed power source has a power failure. Problems such as electrocution or destruction of adjacent power system facilities when re-entering commercial systems.
본 발명의 목적은 상기와 같은 종래 기술의 불편함을 해결하기 위하여, 1차적으로 인버터의 출력전류의 크기를 한번은 지정치의 k% 증가시키고, 다음 한번은 지정치의 k%로 감소시키며, 마지막으로 일정기간 동안은 지정치의 전류크기를 가지도록 하여 주기적으로 동작시켜서 단독운전현상일 때 발생하는 전압변동으로 단독운전현상임을 1차적으로 판단하고, 2차적으로 주파수 변동 방식(Active Frequecny Drift;AFD)을 사용하여 단독운전현상을 검출하는 유효전력 변동방식을 이용한 높은 전력품질의 단독운전 검출 방법을 제공하는 데에 있다.In order to solve the inconvenience of the prior art as described above, an object of the present invention primarily increases the magnitude of the output current of the inverter once by k% of the specified value, and then decreases it by k% of the specified value. Periodically operates by having a current value of a specified value for a certain period of time, it is determined primarily as a stand-alone operation due to voltage fluctuations generated during stand-alone operation, and secondly frequency change method (Active Frequecny Drift (AFD)). It is to provide a high power quality single operation detection method using the effective power fluctuation method that detects the single operation phenomenon using a.
상기 목적을 달성하기 위하여 본 발명의 유효전력 변동방식을 이용한 높은 전력품질의 단독운전 검출 방법에 있어서, 1차적으로 인버터의 출력전류의 크기를 한번은 지정치의 k% 증가시키고, 다음 한번은 지정치의 k%로 감소시키며, 마지막으로 일정기간 동안은 지정치의 전류크기를 가지도록 하여 주기적으로 동작시켜서 단독운전현상을 1차적으로 판단하고, 2차적으로 주파수 변동 방식(Active Frequecny Drift;AFD)을 사용하여 단독운전현상을 검출한다.In order to achieve the above object, in the high power quality single operation detection method using the active power fluctuation method of the present invention, the magnitude of the output current of the inverter is first increased by k% of the designated value, and the next time by the specified value. It is reduced to k%, and lastly, it operates periodically to have a current value of a specified value for a certain period of time, to judge the single operation phenomenon firstly, and to use the frequency variation method (Active Frequecny Drift (AFD)) secondly. To detect single operation.
본 발명에서, 데이터를 샘플링하여 출력 전압의 제로 크로싱이 맞춰지는 단계를 포함하고, 상기 제로 크로싱 상태에서 인버터의 출력전류가 주기적으로 변동되는 단계를 포함한다. 그리고, 상기 출력전류의 변동에 의해 그에 따른 출력전압이 변동되는 단계를 포함하고, 상기 출력전압의 변동 상황에서 상기 출력전류의 주파수 변동 방식을 사용하여 단독운전을 검출하는 단계를 포함하는 것이 바람직하다.In the present invention, the method includes sampling the data to adjust the zero crossing of the output voltage, and periodically changing the output current of the inverter in the zero crossing state. The method may further include a step of varying the output voltage according to the change of the output current, and detecting a single operation using a frequency variation method of the output current in a change state of the output voltage. .
본 발명에서, 상기 인버터의 출력전류의 변동 주기는 한 번은 k% 증가하고, 다음 한번은 k% 감소하며, 그 다음은 일정하게 유지하는 것을 한 주기로 설정하는 것이 바람직하다.In the present invention, it is preferable that the period of variation of the output current of the inverter increases once by k%, then decreases by k%, and then maintains constant by one cycle.
본 발명에서, 상기 실효치 전압의 크기 변화분이 설정 값과 같거나 클 경우에는 주파수를 변동하는 것이 바람직하다.In the present invention, when the magnitude change of the effective value voltage is equal to or larger than the set value, it is preferable to vary the frequency.
본 발명에서, 상기 주파수 변동 방식은 2개의 주기 사이의 실효치 전압의 크기 변화분을 사용하는 것이 바람직하다.In the present invention, it is preferable that the frequency variation method uses a magnitude change of the effective value voltage between two periods.
이하, 본 발명의 바람직한 실시 예를 첨부한 도면을 참조하여 설명하기로 한다. 하기의 각 도면의 구성 요소들에 참조 부호를 부가함에 있어서, 동일한 구성 요소들에 한해서는 비록 다른 도면상에 표시되더라도 가능한 한 동일한 부호를 가지도록 하며, 본 발명의 요지를 불필요하게 흐릴 수 있다고 판단되는 공지 기능 및 구성에 대한 상세한 설명은 생략한다.Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings. In adding reference numerals to components of the following drawings, it is determined that the same components have the same reference numerals as much as possible even if displayed on different drawings, and it is determined that they may unnecessarily obscure the subject matter of the present invention. Detailed descriptions of well-known functions and configurations will be omitted.
도 1 은 본 발명의 일 실시 예에 따른 단독운전현상을 검출하기 위한 플로우차트이다.1 is a flowchart for detecting a single operation phenomenon according to an embodiment of the present invention.
도 1 을 참조하면, 사용하고자 하는 아날로그 신호를 특정간격마다 주기적으로 추출함으로써 디지털로 전환하는 Date Sampling(S100)의 과정을 거친 정보를 얻는다.Referring to FIG. 1, information obtained through a process of date sampling (S100) for converting an analog signal to be used into digital by periodically extracting at a specific interval is obtained.
상기 정보에서 얻어진 출력 전압의 주파수는 정현파인 교류 출력전압에서, (-)값에서 (+)값으로 변하는 순간부터 다음번 (-)값에서 (+)로 변하는 순간까지의 시간을 측정하는 제로 크로싱을 측정하게 된다. The frequency of the output voltage obtained from the above information is zero crossing for measuring the time from the change of the negative value to the (+) value to the next change of the (-) value to the (+) value at the AC output voltage which is a sine wave. Will be measured.
다시 말하면, 상기 동작은 Zero Crossing of Output Voltage(S110) 일 경우에는 다음 동작인 Iinv_pk Periodic Variation(S120)을 실행한다.In other words, in the case of Zero Crossing of Output Voltage (S110), the next operation, Iinv_pk Periodic Variation (S120), is executed.
그리고, 상기 Zero Crossing of Output Voltage(S110)이 되지 않을 경우에는 다음 동작을 실행하지 않고, 상기 출력전압의 제로 크로싱을 다시 맞추도록 한다.When the zero crossing of output voltage (S110) does not occur, the next operation is not executed, and the zero crossing of the output voltage is set again.
상기 Iinv_pk Periodic Variation(S120)은 상기 출력전류의 크기를 주기적으로 변동하는 것으로서, Iinv_pk는 Peak Value of Inverter Current를 의미한다.The Iinv_pk Periodic Variation (S120) periodically changes the magnitude of the output current, and Iinv_pk means Peak Value of Inverter Current.
상기 출력전류의 변동은 인버터의 출력전류의 크기를 그대로 적용하지 않고, 한 번은 지정치의 110%(S200) 다음 한 번은 지정치의 90%(S210)로 전류 크기의 명령을 변화시키고, 마지막으로 일정기간 동안은 지정치의 전류크기(S230) 명령을 인가하여 단독운전의 유무를 판단하여 검출한다.(도 2 참조) The variation of the output current does not apply the magnitude of the output current of the inverter as it is, once the 110% (S200) of the specified value and then once the 90% (S210) of the specified value changes the command of the current magnitude, and finally During a certain period of time, a current magnitude (S230) command of a predetermined value is applied to determine whether or not a single operation is performed.
이때, 상기 지정치의 k%로 전류 크기의 명령을 변화시킬 때, k는 사용자가 임의로 지정한다. At this time, when changing the command of the current magnitude by k% of the specified value, k is arbitrarily designated by the user.
그러나, 상기 인버터의 출력전류의 크기변화에 따른 전압의 변화는 상기 인버터의 출력전류가 아닌 상용계통에 의한 전압 변화와 구별하기 어려운 단점이 있어서, 2차적으로 주파수 변동 방식(Active Frequecny Drift;AFD)을 사용하여 단독운전의 유무를 판단한다.However, the change in voltage according to the change in the magnitude of the output current of the inverter is difficult to distinguish from the change in voltage due to the commercial system, not the output current of the inverter, and thus, a secondary frequency change method (AFD) is used. Use to determine the existence of single operation.
상기 주파수 변동 방식은 2개의 주기 사이의 실효치 전압의 크기 변화분인 △Voltage(RMS)의 값과 설정값(Designed Value)의 크기 차이를 사용하는 방법이다.The frequency variation method is a method of using a difference between a value of ΔVoltage (RMS) and a designed value, which is a change in magnitude of an effective voltage between two periods.
△Voltage(RMS) <= Designed Value(S130) 단계에서는 비교된 값이 △Voltage(RMS) < Designed Value 경우에는 정전이 발생하지 않은 상황으로서 출력전류의 주파수 변동을 일으키지 않아도 된다. 즉, CF(Chopping Fraction)=0(S140)으로 하기 때문에, 전력품질은 높아진다.In step ΔVoltage (RMS) <= Designed Value (S130), when ΔVoltage (RMS) <Designed Value, the power failure does not occur and the frequency of the output current does not need to be caused. That is, since CF (Chopping Fraction) = 0 (S140), the power quality is increased.
상기 비교된 값이 Voltage(RMS) >= Designed Value 경우에는 단독운전이 발생했을 가능성이 높아짐으로, 상기 주파수 변동 방식을 일정기간 사용한다. 여기서, 일정기간이란 상기 주파수 이동방식을 사용했을 경우에 인버터가 정지할 수 있는 충분한 시간으로 주파수 라인 주기는 사용자가 설정하는 값에 따라 달라질 수 있다.When the compared value is Voltage (RMS)> = Designed Value, it is more likely that single operation has occurred, and thus the frequency variation method is used for a certain period of time. Here, the predetermined time period is a sufficient time for the inverter to stop when the frequency shift method is used. The frequency line period may vary according to a value set by the user.
상기 주파수 변동 방식을 사용하였을 경우에, 측정된 인버터 출력전압의 주파수 크기가 60Hz 보다 크거나 같으면(Freqv>=60)(S150), 주파수 변동이 60Hz보다 커지게 하기 위해 (+)값의 CF0을(S160) 투입시킨다.In the case of using the frequency variation method, if the frequency magnitude of the measured inverter output voltage is greater than or equal to 60 Hz (Freq v > = 60) (S150), CF0 of positive value is set to make the frequency variation larger than 60 Hz. (S160) is injected.
그리고, 상기 측정된 인버터의 출력전압의 주파수 크기가 60Hz 보다 작을경 우에는 60Hz 이하의 방향으로 주파수를 변동시키기 위해 (-) 값의 CF0을(S170) 투입시킨다.When the frequency magnitude of the measured output voltage of the inverter is smaller than 60 Hz, CF0 of negative value (S170) is input to change the frequency in a direction of 60 Hz or less.
상기 CF0의 값은 상수값으로, 사용자가 임의로 결정하여 사용할 수 있다.The value of CF0 is a constant value and can be arbitrarily determined by a user.
Islanding Confirmed(S180) 단계에서는 상기 CF 값을 정해진 주기동안 투입하였을 때, 단독운전상태라고 판단될 경우에 인버터를 정지시키며, 상기 인버터가 정지를 되지 않는다면, 단독 운전상태가 아니라고 판단하여 CF=0(S190)으로 하여 초기 상태로 돌아간다.In the Islanding Confirmed (S180) step, when the CF value is input for a predetermined period, the inverter is stopped when it is determined to be in the stand-alone operation state. S190) to return to the initial state.
본 발명에 의하면, 단독 운전 발생 시점을 출력전압의 변동으로 판별한 뒤, 2차 보충 판별법으로 AFD(Active Frequecny Drift) 기법을 사용하였으나, 이외에 AFDPF(Active Frequecny Drift with Positive Feedback) 방법 혹은 SMS(Slip Mode frequency Shift) 방법 등 다른 기법들을 응용하여 사용할 수 있다.According to the present invention, after determining the occurrence of single operation by the variation of the output voltage, AFD (Active Frequecny Drift) technique is used as the secondary supplemental discrimination method, but in addition, AFFF (Active Frequecny Drift with Positive Feedback) method or SMS (Slip) Other techniques such as the mode frequency shift method can be used.
도 3 은 본 발명의 일 실시 예에 따른 단독운전현상을 검출하기 위한 인버터의 출력전류와 출력전압의 그래프이고, 도 4 는 본 발명의 일 실시 예에 따른 과주파수 계전기와 저주파수 계전기를 사용한 단독운전 검출을 나타낸 그래프이다.3 is a graph of an output current and an output voltage of an inverter for detecting a standalone operation according to an embodiment of the present invention, and FIG. 4 is a standalone operation using an overfrequency relay and a low frequency relay according to an embodiment of the present invention. Graph showing detection.
도 3 을 참조하면, 인버터의 실효치 전류(I(RMS))를 샘플링하여 나타낸 그래프를 보면, 상기 실효치 전류(I(RMS))는 지정치(N)의 크기로 전송될 때, 일정한 전류 변화량(K)을 지정하여 주는데, 한번은 상기 전류 변화량(K)만큼 증가시키고, 다음 한번은 상기 전류 변화량(K)만큼 감소시키며, 그 다음에는 일정시간 동안 상기 지정치(N)의 크기로 흐르며, 이에 따라 한 주기(C)를 이룬다.Referring to FIG. 3, when the effective value current I (RMS) of the inverter is sampled, the graph shows that the effective value current I (RMS) is a constant amount of current change when transmitted at a predetermined value N. K) is specified, one time increases by the current change amount K, the next time decreases by the current change amount K, and then flows to the size of the specified value N for a predetermined time. Attain cycle C.
단독운전이 발생했을 경우(T1)에는, 상기 전류 변화량(K)에 해당하는 전압 변동분(△V(RMS))이 발생하게 된다. 이때 상기 전압 변동분(△V(RMS))이 설정 값 이상이 되면 주파수 변동 방식(AFD)이 투입(T2)되어 주파수 변동을 일으키고, 상기 주파수 변동에 따라 주파수 계전기가 작동되며, 상기 주파수 계전기의 작동에 의해 인버터를 정지시켜 단독운전 현상을 검출(T3)한다.When single operation occurs (T1), a voltage variation ΔV (RMS) corresponding to the current change amount K is generated. In this case, when the voltage variation ΔV (RMS) is equal to or greater than a set value, the frequency variation method AFD is inputted T2 to cause a frequency variation, and the frequency relay is operated according to the frequency variation, and the frequency relay is operated. The inverter is stopped to detect an independent operation phenomenon (T3).
그리고, 단독운전이 발생하기 전에는 상용계통의 상태나 전압의 계측 오차로 인해 출력전압 주파수(Freg)가 60Hz보다 클 수도 있고, 적을 수도 있다. 이에 따라, 단독운전현상을 빠르게 검출하기 위하여, 상기 주파수 변동 방식(AFD)을 사용(T2)한다.Before the single operation occurs, the output voltage frequency Freg may be greater than or less than 60 Hz due to the state of a commercial system or a measurement error of the voltage. Accordingly, in order to quickly detect a single operation phenomenon, the frequency variation method AFD is used (T2).
상기 출력전압 주파수(Freg)가 60Hz보다 큰 경우에는, (+)값의 CF0을 투입하고, 주파수 변동에 의한 상기 출력전압 주파수(Freg)의 값이 과주파수 계전기(OFR)의 설정지점에 도달하게 되면 인버터를 정지시켜 단독운전 현상을 검출(T3)한다.If the output voltage frequency Freg is greater than 60 Hz, CF0 of a positive value is inputted so that the value of the output voltage frequency Freg due to the frequency variation reaches the set point of the overfrequency relay OFR. When the inverter is stopped, the single operation phenomenon is detected (T3).
상기 출력전압 주파수(Freg)가 60Hz보다 작은 경우에는, (-)값의 CF0을 투입하여 주파수 변동에 의한 상기 출력전압 주파수(Freg)의 값이 저주파수 계전기(UFR) 설정지점에 도달하면, 인버터를 정지시키고 단독운전 현상을 검출(T3)한다. (도 4 참조)If the output voltage frequency Freg is less than 60 Hz, input CF0 of a negative value and when the value of the output voltage frequency Freg due to the frequency variation reaches the low frequency relay UFR set point, the inverter is turned off. It stops and detects a single operation phenomenon (T3). (See Figure 4)
즉, 단독운전이 발생(T1)하여 상기의 출력 전압 변동분(△V(RMS))이 설정 값 이상이 되면, 상기 주파수 변동 방식(AFD)을 투입(T2)하여 주파수 변동에 따라 과주파수 계전기(OFR) 또는 저주파수 계전기(UFR)을 사용하여 인버터를 정지시킴으로써 단독운전 현상을 검출(T3)한다.That is, when the single operation occurs (T1) and the output voltage variation ΔV (RMS) becomes equal to or greater than the set value, the frequency variation method AFD is inputted (T2) to overfrequency relay ( The solenoid phenomenon is detected (T3) by stopping the inverter using OFR) or a low frequency relay (UFR).
상기의 방법을 사용함에 따라, 단독운전이 발생하기 전 인버터의 출력전류의 크기변화는 인버터 출력전력품질에 악영향을 끼치지 않고 높은 전력품질을 유지하며, 일정기간 동안 지정치의 전류명령을 인가함으로써 계통에 대한 충격을 완화시킨다.According to the above method, the change of the magnitude of the output current of the inverter before the single operation occurs does not adversely affect the inverter output power quality and maintains high power quality, and by applying the current command of the specified value for a certain period of time. Mitigates the impact on the system.
그리고, 출력전류의 크기를 증가시키는 만큼 감소시킴으로 출력전력의 평균량을 동일하게 하여 이러한 전류 크기 변화는 인버터의 DC Link 커패시터에 충방전 전류로 나타남으로 인해서 태양광 발전의 경우 태양전지 입력의 최대 전력 추종 성능에 영향을 끼치지 않는다.And, by decreasing the size of the output current by increasing the average amount of output power equal to this amount of current changes due to the charge and discharge current in the DC Link capacitor of the inverter, the maximum power of the solar cell input in the case of solar power generation Does not affect tracking performance.
상기와 같이, 본 발명의 바람직한 실시 예를 참조하여 설명하였지만 해당 기술 분야의 숙련된 당업자라면 하기의 특허청구범위에 기재된 본 발명의 사상 및 영역으로부터 벗어나지 않는 범위 내에서 본 발명을 다양하게 수정 및 변경시킬 수 있음을 이해할 수 있을 것이다.As described above, it has been described with reference to a preferred embodiment of the present invention, but those skilled in the art various modifications and changes of the present invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.
상술한 바와 같이 본 발명에 따르면, 전류 크기를 증가시키는 만큼 다음에 감소시키므로, 발전시키는 출력전력의 평균량을 동일하게 하여 고조파나 역률에 악영향을 끼치지 않음으로 전력품질을 우수하게 하는 효과가 있다.As described above, according to the present invention, since the current is reduced by increasing the magnitude of current, the average amount of output power to be generated is the same, so that it does not adversely affect harmonics or power factor, thereby improving power quality. .
또한, 일정기간 동안은 지정치의 전류 명령을 인가함으로 상용계통에 대한 충격을 완화하는 효과가 있다.In addition, by applying a current command of a predetermined value for a certain period of time there is an effect to mitigate the impact on the commercial system.
그리고, 단독운전 검출 성능이 우수하여 계통유지 요원의 감전사나 혹은 상 용계통 재투입시 인접 전력 계통 설비의 파괴를 방지하는 효과가 있다.In addition, the excellent operation performance of the detection of the operation alone has the effect of preventing the destruction of the adjacent power system facilities when the system maintenance personnel electrocution or re-entry the commercial system.
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101048290B1 (en) * | 2009-12-18 | 2011-07-13 | 한국전기연구원 | Active single operation detection method and apparatus of distributed power supply using voltage positive feedback control |
| CN103645404A (en) * | 2013-12-16 | 2014-03-19 | 辽宁工业大学 | Micro-grid islanding detection method |
| CN103760434A (en) * | 2013-12-27 | 2014-04-30 | 浙江工业大学 | Self-adaption phase deviation island detection method based on fuzzy control |
| WO2015174569A1 (en) * | 2014-05-16 | 2015-11-19 | 공주대학교 산학협력단 | Afd islanding detection module for solar photovoltaic inverter system and afd islanding detection method using same |
| CN107329514A (en) * | 2017-06-28 | 2017-11-07 | 青岛大学 | A kind of periodic voltage or electric current quick sampling adjusting method |
| CN112462181A (en) * | 2020-11-20 | 2021-03-09 | 哈尔滨理工大学 | Distributed inverter grid-connected system island detection method based on phase angle random disturbance |
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2006
- 2006-11-13 KR KR1020060111675A patent/KR20080043088A/en not_active Application Discontinuation
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101048290B1 (en) * | 2009-12-18 | 2011-07-13 | 한국전기연구원 | Active single operation detection method and apparatus of distributed power supply using voltage positive feedback control |
| CN103645404A (en) * | 2013-12-16 | 2014-03-19 | 辽宁工业大学 | Micro-grid islanding detection method |
| CN103760434A (en) * | 2013-12-27 | 2014-04-30 | 浙江工业大学 | Self-adaption phase deviation island detection method based on fuzzy control |
| WO2015174569A1 (en) * | 2014-05-16 | 2015-11-19 | 공주대학교 산학협력단 | Afd islanding detection module for solar photovoltaic inverter system and afd islanding detection method using same |
| CN107329514A (en) * | 2017-06-28 | 2017-11-07 | 青岛大学 | A kind of periodic voltage or electric current quick sampling adjusting method |
| CN112462181A (en) * | 2020-11-20 | 2021-03-09 | 哈尔滨理工大学 | Distributed inverter grid-connected system island detection method based on phase angle random disturbance |
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