Abstract
Large-scale photovoltaic power station access to the grid will profoundly change the fault current characteristics of the power station’s outgoing lines. This change results in adaptive problems in traditional protection phase selection components, which may cause incorrect actions in reclosing, protection ranging, and distance protection. Based on the fault current characteristics of the large-scale photovoltaic power station transmission line, this paper analyzes the adaptability of the phase current difference mutation and the sequence component phase selection component in protecting the Photovoltaic (PV) power plant side of the transmission line. Based on the fault current analytical formula, the phase relationship between the phase current difference and the current sequence component under different control targets, such as suppressing negative sequence current, suppressing the active power fluctuation, and suppressing the reactive power fluctuation, is derived. The operational performances of the phase–phase current difference of the abrupt phase selection component and the sequence component phase selection component of the power station side are degraded, which may cause incorrect operation of the phase selection component. Based on the actual engineering parameters of a PV power plant, a simulation model was built in Power System Computer Aided Design (PSCAD) to verify the correctness of the theoretical analysis.
Highlights
With the continued improvement of photovoltaics, photovoltaic power generation technology has been transformed from initial small-capacity distributed access to the development and utilization of large-scale centralized photovoltaic power plants [1]
Based on the actual engineering parameters of a 150 MW PV power plant, the simulation model shown in Figure 1 was built in Power System Computer Aided Design (PSCAD)/EMTDC: The PV power plant capacity was 150 MW; a total of seven collection lines of 35 kV were included, and the main transformer rated capacity was 200 MVA, with a rated transformation ratio of 230:37 kV, an YNd11 wiring group, a short circuit impedance of 16%; a delivery line voltage level of 220 kV, a line length of 5.334 km, and with positive sequence and zero-sequence impedances of 0.107 + 0.427 Ω/km, 0.535 + j1.153 Ω/km, respectively
Based on the fault current characteristics of the large-scale photovoltaic power station transmission line, this paper analyzes the adaptability of the abrupt change in the phase current difference and the sequence component phase selection components in the protection of the PV power plant side
Summary
With the continued improvement of photovoltaics, photovoltaic power generation technology has been transformed from initial small-capacity distributed access to the development and utilization of large-scale centralized photovoltaic power plants [1]. The access of large-scale photovoltaic power plants to the grid has profoundly changed the fault characteristics of traditional power grids. When the negative sequence current is suppressed as the control target of the grid-connected inverter, there is no negative sequence current in the fault current of the photovoltaic power station side. There is much literature on the effects of inverter-type new energy access to the grid on distance protection, reclosing, and differential protection [3,4,5,6,7,8]. The authors in [3] analyze
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