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Detection and control of the island effect solar generator
Detection and control of the island effect solar generator
Detection and control of the island effect solar generator
Inverter power grid directly, must not only have basic protection functions, also has the special function of anti-islanding. From the safe use of electricity and electric energy quality into consideration, the island effect is not allowed; islanding occurs must be fast, accurate removal of grid-connected inverter, which leads to the islanding detection control.
Islanding detection is generally divided into passive and active. Passive detection is the use of grid monitoring conditions such as voltage, frequency, phase as the judgment whether the basis of grid fault. If it matched with the inverter output load network, passive method will not be able to detect islanding occurs. Active detection method is through the power inverter timing of interference signals, in order to observe the grid are affected as the basis of judgment, such as injection method, pulse current output power change detection method, active frequency drift method and sliding mode frequency shift method etc.. They have been applied in actual grid-connected inverter, but there are also shortcomings. When the voltage amplitude and frequency range is less than a certain value, the frequency offset method can't detect islanding effect, there is "the detection blind area. The output power change detection method is not the existence of "blind area", but the photovoltaic grid-connected system affected by illumination effects, the PV output power at any time in the fluctuation of the inverter, adding active power disturbance, will reduce the efficiency of photovoltaic array and the inverter system. In order to solve this problem, the PV grid-connected power and without power control method are proposed.
With the wide application of PV grid-connected system further, when the plurality of inverter and grid-connected inverter output, change is very large, leading to possible failure above method. Therefore, research on inverter grid-connected communication, the cooperative control has become a research trend detection and control of the island effect.
Inverter power grid directly, must not only have basic protection functions, also has the special function of anti-islanding. From the safe use of electricity and electric energy quality into consideration, the island effect is not allowed; islanding occurs must be fast, accurate removal of grid-connected inverter, which leads to the islanding detection control.
Islanding detection is generally divided into passive and active. Passive detection is the use of grid monitoring conditions such as voltage, frequency, phase as the judgment whether the basis of grid fault. If it matched with the inverter output load network, passive method will not be able to detect islanding occurs. Active detection method is through the power inverter timing of interference signals, in order to observe the grid are affected as the basis of judgment, such as injection method, pulse current output power change detection method, active frequency drift method and sliding mode frequency shift method etc.. They have been applied in actual grid-connected inverter, but there are also shortcomings. When the voltage amplitude and frequency range is less than a certain value, the frequency offset method can't detect islanding effect, there is "the detection blind area. The output power change detection method is not the existence of "blind area", but the photovoltaic grid-connected system affected by illumination effects, the PV output power at any time in the fluctuation of the inverter, adding active power disturbance, will reduce the efficiency of photovoltaic array and the inverter system. In order to solve this problem, the PV grid-connected power and without power control method are proposed.
With the wide application of PV grid-connected system further, when the plurality of inverter and grid-connected inverter output, change is very large, leading to possible failure above method. Therefore, research on inverter grid-connected communication, the cooperative control has become a research trend detection and control of the island effect.
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