Wide‐area measurement system‐based online calculation method of PV systems de‐loaded margin for frequency regulation in isolated power systems

Abstract

This study proposes a photovoltaic (PV) systems de-loaded margin online calculation method that allows PVs to participate in isolated power system frequency regulation with a proper de-loaded margin. The de-loaded margin determines PVs' frequency regulation capacity. The larger de-loaded margin of PVs provides more reserve capacity for frequency regulation, while more economic benefits are sacrificed correspondingly. Therefore, a tradeoff between PVs' economic benefit and their frequency regulation reserve capacity is necessary. Taking into account these two factors, a dynamic calculation method of PVs optimal de-loaded margin based on the systems real-time operation condition is proposed. Real-time monitoring of the systems operation condition is realised by wide-area measurement system. The calculated de-loaded margin can meet the system frequency regulation requirement with PVs' minimum economic loss. RTDS simulation is conducted in an actual industrial isolated system driven by thermal power and PVs to verify the effectiveness of the proposed method.

Active Power Dispatch for Supporting Grid Frequency Regulation in Wind Farms Considering Fatigue Load

“…where ω g is the measured generator speed; B is the main shaft viscous friction coefficient. According to (11) and (12),…”

“…These matrices change every other dispatch cycle. Then, the continuous state space model is discretized with the sampling period t s , which is Substituting (6) and (11), the shaft torque T s can be calculated by…”

“…Wind power generally does not participate in frequency regulation due to the decoupling of the WT rotor and the grid frequency, so large-scale wind power access to the grid will significantly weaken the frequency regulation capability of the grid [9,10]. With the continuous increase of the wind power penetration rate, the influence of wind power volatility and uncertainty on the frequency regulation of power systems is also increasing [11][12][13][14][15]. In order to meet grid frequency requirements, active power control (APC) method for wind power is critical to actively maintaining a balance between power generation.…”

Flexible power‐point‐tracking‐based frequency regulation strategy for PV system

“…However, unlike conventional generators, PV systems have no natural inertia and must reserve some of the available power to participate in the system frequency response [8][9][10]. In principle, there is two methods for implementing the power reserve: (i) installation of an energy storage device, such as a battery or a supercapacitor, which has the disadvantage of increasing the system maintenance costs and complexity [5,8,[11][12][13][14][15]; (ii) operation of PV systems at a suboptimal power point to reserve partial frequency regulation power, which is simple and costeffective [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31]. This study is focused on the latter method.…”

“…The second category is to estimate MAP by the offline or online fitting. In [21][22][23], the offline fitting function is used to estimate the parameters of the PV array, and then, the MAP is calculated from measurements of irradiance and temperature. However, the main shortcoming of this method is the need for additional sensors, especially the expensive irradiance sensor.…”