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Abstract This paper discusses the power variation of photovoltaic power plant (PVPP) impact on the frequency response of an isolated island microgrid. An island microgrid with PVPPs and diesel generators is selected for study. The power system network, diesel generation units, load and PVPP data are collected in detail. And the one-line diagram of the study system with regarding peak and off-peak loading is set up in the simulation software for the steady state load flow analysis. After that, the transient stability analysis is executed with considering the tripping and power variation of various PVPP ramp rates with and without considering the over frequency compensation of photovoltaic (PV) inverters. The dynamic response of diesel generators and system frequency are examined carefully. It is found that the over frequency phenomenon can be controlled effectively by the regulation of PV inverters to achieve better reliability of the microgrid. [ABSTRACT FROM AUTHOR]

To enhance the outage quality of a distribution system with a high penetration of photovoltaic (PV) renewable energy, this paper proposes a coordinating control strategy for an on-load tap changer (OLTC) of the main transformer in a distribution substation and PV smart inverters. The voltages at the end points of all distribution feeders that are served by the main transformer and the power generation of each PV system are collected using a SCADA system. The hourly tap position of the OLTC is then derived from the daily profiles of feeder voltage and the injected power that is generated by all PV systems along the feeder. Thereafter, the PV smart inverters perform autonomous control of reactive power compensation so that the voltage at the point of common coupling can be fixed at the specified voltage level. To demonstrate the effectiveness of the proposed voltage-control strategy, a main transformer, which serves six feeders of the Taiwan Power Company(Taipower) with high PV penetration, was considered in a case study. The proposed coordinating control of the OLTC and PV smart inverters dramatically improved the voltage quality of the distribution feeder and enabled the effective mitigation of the impact of large PV integration in the distribution system. [ABSTRACT FROM AUTHOR]

This paper proposes an innovative transformer management system (TMS) for energy control of customer loads and photovoltaic (PV) systems to solve the problems of transformer overloading and overvoltage due to power injection by PV renewable energy. The operation status of distribution transformers is monitored by transformer terminal unit (TTU) and reported to the control master station via the hybrid communication system. The demand response of customer load control is activated to reduce the loading level of transformers for mitigation of overloading problem. For the residential customers with installation of roof top PV system, the TTU is applied to perform the power factor control of smart inverter to prevent the overvoltage problem. The hybrid communication system consisting of power line carrier, LoRa radio frequency, and optical fiber is used to provide two-way communication for data collection and controls of customer loads and PV system. According to the field testing of the proposed TMS in Taiwan Power Company, the adaptive energy control of customer loads by TTU is executed when the overloading problem of distribution transformer occurs. The TTU also performs the power factor control of PV smart inverters to solve the overvoltage problem due to too much of PV power being injected during the solar peak period. The overvoltage problem due to PV power injection has also been solved by TTU for control of PV smart inverters to perform the proper reactive power compensation. [ABSTRACT FROM AUTHOR]

The PV penetration level of a distribution system is often limited by the violation of voltage variation caused by large intermittent power generation. This study investigates the use of a distribution static compensator (DSTATCOM) in reactive power compensation for system voltage control, during peak solar irradiation, in order to increase the PV installation capacity of a distribution feeder and avoid the voltage violation problem. PV power generation is simulated using hourly solar irradiation and temperature data provided by the weather bureau. The voltage variation at the point of common coupling (PCC) is also derived by executing the 3-\varphi load flow analysis to determine the maximum PV power injection without causing voltage violation. By applying the proposed voltage control scheme of DSTATCOM during high solar irradiation periods, the total power generation and the total energy delivered by the PV system over one year are determined according to the annual duration of solar irradiation. The annual sales of PV power, the system O&M cost, the cost of DSTATCOM installation and the initial capital investment for a PV system are then used to calculate the cash flow over the system life-cycle and the final net present value (NPV) of the PV project. With the proposed DSTATCOM voltage control to perform reactive power compensation, the optimal installation capacity of PV systems can be determined by maximizing the net present value of the system to ensure the best cost-effectiveness of the PV project and to better utilize solar energy. [ABSTRACT FROM PUBLISHER]

Abstract: This paper investigates a simulated stadium-scale photovoltaic generation system (PVGS) impact on energy demand and its financial analysis. By applying the limit of voltage variation ratio on the system, the PVGS with a maximum capacity of 690 kWp is supposed to be constructed in the National Main Stadium (NMS) in Kiribati. Meanwhile, the voltage variation and system loss of the power grid are analyzed by executing the load flow analysis with and without considering the impact of the PVGS. Also, the payback years (PBY) and the internal rate of return (IRR) of the PVGS are derived considering the cash flow of annual power generation, the operation cost, the maintenance cost and the capital investment costs of the PVGS. It is concluded that although the selling price of PV generation has to be designed according to the conditions of solar irradiation and temperature so that sufficient incentives can be provided. [Copyright &y& Elsevier]

To promote the photovoltaic (PV) installation, a large-scale PV system installed in the Main Stadium of the 2009 World Games has been investigated for the design of selling price of PV power generation. The PV power generation is simulated according to the hourly solar irradiation and temperature provided by the weather bureau. The cash flow of annual power generation, the O&M cost, and the capital investment cost of the PV system is then used to derive the payback years and the internal rate of return for the PV system under different selling price of PV power generation. The voltage variation and the power system loss of the distribution feeder, which serves the Main Stadium, are also performed by executing the 3-\varphi load flow analysis for the impact analysis of the PV system. The results indicate that the reduction of voltage drop and power system loss can be obtained with the PV system installed to provide the dispersed generation for the local loads. However, the PV system penetration is limited due to the violation of voltage variation introduced by the large intermittent PV power generation. The selling price of PV generation has to be designed according to the conditions of solar irradiation and temperature so that sufficient incentives can be provided to encourage more customers to participate the PV program. [ABSTRACT FROM AUTHOR]