Equivalent Model of Photovoltaic Power Station Considering Different Generation Units’ Fault Current Contributions

Abstract

The fault current calculation model of photovoltaic (PV) power stations is usually treated as a capacity weighted equivalent model of a single PV generation unit (PVGU). However, in the same PV power station, different PVGUs have various fault current characteristics. As a result, there are significant differences in fault current characteristics between a PVGU and a PV power station. It means that the existing capacity weighted equivalent model cannot be used for accurately describing the fault current contributions from a practical PV power station. In this paper, the fault behaviors of the PVGUs located at different access points of a PV power station are firstly analyzed. The difference in PVGUs’ fault current contributions is identified and reflected with the activation states of current limiters that are employed for PV inverters. The activation states are represented by a theoretical expression so as to distinguish the PVGUs’ fault contributions. Further, based on the proposed theoretical expression, a novel algorithm is developed for sorting all PVGUs included in a PV power station. The multi-machine calculation model is deduced in order to exactly express the fault current contribution from a PV station. Finally, some simulation tests are conducted. The tested results verify the effectiveness of the proposed calculation model. It can provide support for calculating the protection setting of power grid connected with large-scale PV stations.

Fast frequency response technology of photovoltaic power plant based on equivalent modelling

“…In formula (8), w is any photovoltaic power generation unit in the radial topology after the trunk line conversion, 1 ≤ w ≤ z, R x are the actual impedance of the collector line of the x photovoltaic power generation unit in the trunk line topology, P x is the power flowing through the impedance R x of the collector line, and R eqw is the equivalent impedance of the collector line of the w photovoltaic power generation unit in the radial topology.…”

“…The results show that the fast frequency responses of the two PVs can be performed independently without affecting each other. Reference [8] analyzed the fault behavior of different access points photovoltaic glass units (PVGU) in photovoltaic power stations. The difference of PVGU fault current contribution is identified and reflected by the active state of the current limiter used for the PV inverter.…”

Optimization and Control of New Power Systems under the Dual Carbon Goals: Key Issues, Advanced Techniques, and Perspectives

“…Guo Z M et al [20] proposed a parameter extraction technique based on a metaheuristic algorithm (i.e., the artificial rabbits optimization algorithm) for the double diode model of photovoltaic cells and the electrochemical model of solid oxide fuel cells to establish an accurate model of photovoltaic cells and fuel cells, and the established model can highly simulate the static output characteristics of the above hybrid power generation system under various operating scenarios. To address the problem that the traditional equivalent model of PV plants cannot reflect the discrepancy of fault currents of different PV power units, Liu S M et al [21] used the activation state of the current limiter of PV inverters to quantify the fault current contribution of different PV units and classified the PV units accordingly. This has important practical significance for the design and optimization of relay protection for large-scale low-inertia photovoltaic power plants.…”