“…The resonant frequency of the RLC load is the same as grid line frequency. Usually unity power factor condition combined with the RLC load, the worst case of islanding detection when the active power or the reactive power is 100% match between the load and the DG output [2], [7]. The experiment will build Islanding condition by off-grid (off switch) between the Point of Common Coupling (PCC) and Utility.…”
Section: Experiments and Resultsmentioning
confidence: 99%
“…NDZ of OUV/OUF of Inverter-Based DG Zhihong Ye, Amol Kolwalkar, Yu Zhang, Pengwei Du, and Reigh Walling propose a nondetection zone (NDZ) of inverter-based DG as a performance index to evaluate different anti-islanding schemes. The NDZ for under/over voltage and under/over frequency are derived analytically and validated by PSCAD simulation [7], [12].…”
Section: Islanding Conditionmentioning
confidence: 99%
“…Therefore, investigation relationship between voltage and NDZ of OUV of local islanding detection techniques by used inverter-based DG, the NDZ of active power of inverter-based DG [7], [12] is 2 2 max min…”
Section: ) Case Of Inverter-based Dgmentioning
confidence: 99%
“…Comparison is measured voltage at PCC point (V PCC ) if V PCC > 110% or V PCC < 88% shown that islanding condition occurs [6]. Usually Nondetection Zone (NDZ) of islanding detection techniques is difficult evaluation but some techniques have effort such phase jump [7], active frequency drift (AFD) [8] and Sandia frequency shift (SFS) [9]. Especially OUV/OUF of islanding detection techniques can evaluation of NDZ by Inverter-based DG and evaluation of NDZ by Synchronous Distributed Generator (SDG) [7], [10].…”
mentioning
confidence: 99%
“…Usually Nondetection Zone (NDZ) of islanding detection techniques is difficult evaluation but some techniques have effort such phase jump [7], active frequency drift (AFD) [8] and Sandia frequency shift (SFS) [9]. Especially OUV/OUF of islanding detection techniques can evaluation of NDZ by Inverter-based DG and evaluation of NDZ by Synchronous Distributed Generator (SDG) [7], [10]. Furthermore, over/under voltage (OUV) of islanding detection technique has been used in inverters such grid-connected inverter of Sunnergy Technology Co., Ltd., Thailand.…”
Abstract-The objective of this paper is to investigate relationship between voltage and nondetection zone of OUV/OUF of local islanding detection techniques of distributed generation in electric power system network. This paper shows experimental results of inverter-based DG and synchronous-based DG with parallel RLC load that causes the most difficulty in detection. The experiments have shown that, case of inverter-based DG: variation of active power associated with variation of off-grid voltage at V PCC , case of synchronous-based DG: variation of off-grid voltage at V PCC was not associate with variation of active power but variation of off-grid voltage at V PCC associated with variation of reactive power. Nondetection zone of OUV of synchronous-based DG are very possibility that Q can more than -9.6 MVAR or Q can less than 3.6 MVAR which they can affect the V PCC to outside of normal voltage range when islanding condition is happen.
“…The resonant frequency of the RLC load is the same as grid line frequency. Usually unity power factor condition combined with the RLC load, the worst case of islanding detection when the active power or the reactive power is 100% match between the load and the DG output [2], [7]. The experiment will build Islanding condition by off-grid (off switch) between the Point of Common Coupling (PCC) and Utility.…”
Section: Experiments and Resultsmentioning
confidence: 99%
“…NDZ of OUV/OUF of Inverter-Based DG Zhihong Ye, Amol Kolwalkar, Yu Zhang, Pengwei Du, and Reigh Walling propose a nondetection zone (NDZ) of inverter-based DG as a performance index to evaluate different anti-islanding schemes. The NDZ for under/over voltage and under/over frequency are derived analytically and validated by PSCAD simulation [7], [12].…”
Section: Islanding Conditionmentioning
confidence: 99%
“…Therefore, investigation relationship between voltage and NDZ of OUV of local islanding detection techniques by used inverter-based DG, the NDZ of active power of inverter-based DG [7], [12] is 2 2 max min…”
Section: ) Case Of Inverter-based Dgmentioning
confidence: 99%
“…Comparison is measured voltage at PCC point (V PCC ) if V PCC > 110% or V PCC < 88% shown that islanding condition occurs [6]. Usually Nondetection Zone (NDZ) of islanding detection techniques is difficult evaluation but some techniques have effort such phase jump [7], active frequency drift (AFD) [8] and Sandia frequency shift (SFS) [9]. Especially OUV/OUF of islanding detection techniques can evaluation of NDZ by Inverter-based DG and evaluation of NDZ by Synchronous Distributed Generator (SDG) [7], [10].…”
mentioning
confidence: 99%
“…Usually Nondetection Zone (NDZ) of islanding detection techniques is difficult evaluation but some techniques have effort such phase jump [7], active frequency drift (AFD) [8] and Sandia frequency shift (SFS) [9]. Especially OUV/OUF of islanding detection techniques can evaluation of NDZ by Inverter-based DG and evaluation of NDZ by Synchronous Distributed Generator (SDG) [7], [10]. Furthermore, over/under voltage (OUV) of islanding detection technique has been used in inverters such grid-connected inverter of Sunnergy Technology Co., Ltd., Thailand.…”
Abstract-The objective of this paper is to investigate relationship between voltage and nondetection zone of OUV/OUF of local islanding detection techniques of distributed generation in electric power system network. This paper shows experimental results of inverter-based DG and synchronous-based DG with parallel RLC load that causes the most difficulty in detection. The experiments have shown that, case of inverter-based DG: variation of active power associated with variation of off-grid voltage at V PCC , case of synchronous-based DG: variation of off-grid voltage at V PCC was not associate with variation of active power but variation of off-grid voltage at V PCC associated with variation of reactive power. Nondetection zone of OUV of synchronous-based DG are very possibility that Q can more than -9.6 MVAR or Q can less than 3.6 MVAR which they can affect the V PCC to outside of normal voltage range when islanding condition is happen.
Summary
Many issues are arising during the operation like interruption, disorder, and uncertainty in energy systems. One of the situations is islanding and that is required to protect humans and converter devices, those are working in interconnected electrical energy system environment. Variable converter pulse (VCP) method is proposed to identify the islanding detection (ISD) with rate of change of under/over voltage and rate of change of under/over frequency. Adaptive ISD algorithm is developed for proper tuning of VCP and used to identify ISD events in integrated utility grid. When a network is extended by means of new small‐scale energy systems that is, distributed generation (DG) and operating with main grid network, the possibility of pre‐existence of ISD data is also reconsidered for generating trip signal to isolate DG. In this paper, updating VCP‐based control as function of change in voltage and frequency at point of common coupling (PCC) with island events and non‐island events. Number of pulses and those are variable during island conditions and updated control vector to meet an objective of proposed ISD method. Especially multiple DG connected to PCC is also addressed in proposed method.
To carry out the study and simulations of anti-islanding systems, it is necessary to take into account the generic system proposed by the IEEE 929-2000 and IEEE 1547 standards, where the network, the RLC load, and PV inverter are connected in parallel to the PCC. The IEEE 929-2000 standard defines the quality factor to have a standard test condition. The paper presents a modified Active Frequency Drift (AFD) algorithm to detect the islanding of grid-connected photovoltaic (PV) systems with low harmonics levels without degrading their power factor.Severe issues such as deterioration in power quality and electric shock can occur when a PV inverter operates in islanding mode. Various islanding detection techniques have been investigated in the literature in the last two decades among which, AFD is a typical method. However, a prominent drawback of AFD is its relatively large Non-Detection Zone (NDZ). The improved AFD method that this paper suggests allows the frequency of the inverter current to be controlled slightly lower (or higher) than the frequency of the terminal voltage. The islanding condition is detected by calculating the changing parameter that relates to the change of the chopping fraction and the line frequency periodically. The frequency deviation is then detected to determine the chopping and a changing parameter, which accumulates to the threshold value when the inverter is shut down. The proposed algorithm overcomes the conventional AFD issues by improving the accuracy of detection, eliminating the NDZ, and reducing the current harmonic distortion. The proposed method is validated with the help of simulated and experimental results of a 350 W PV inverter using IEEE Standards.
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