Hosting Capacity of the Power Grid for Renewable Electricity Production and New Large Consumption Equipment

Abstract

After a brief historical introduction to the hosting-capacity approach, the hosting capacity is presented in this paper as a tool for distribution-system planning under uncertainty. This tool is illustrated by evaluating the readiness of two low-voltage networks for increasing amounts of customers with PV panels or with EV chargers. Both undervoltage and overvoltage are considered in the studies presented here. Probability distribution functions are calculated for the worst-case overvoltage and undervoltage as a function of the number of customers with PV or EV chargers. These distributions are used to obtain 90th percentile values that act as a performance index. This index is compared with an overvoltage or undervoltage limit to get the hosting capacity. General aspects of the hosting-capacity calculations (performance indices, limits, and calculation methods) are discussed for a number of other phenomena: overcurrent; fast voltage magnitude variations; voltage unbalance; harmonics and supraharmonics. The need for gathering data and further development of models for existing demand is emphasised in the discussion and conclusions.An international working group [22] recently presented a number of recommendations, key findings and open issues to be addressed because of the integration of solar power. Recommendations were given for a number of power-quality phenomena, including harmonics, supraharmonics, fast voltage variations (faster than 10-min time scale), slow voltage variations (slower than 10 min), overvoltage, flicker, and voltage unbalance. The hosting capacity approach, as was proposed by an international cooperation project in 2004 (see Section 2) is put forward in the report as an important tool for quantifying the impact of solar power on the power system. Additional work is needed, according to the report, for establishing suitable performance indices and corresponding limits.This paper consists of three main parts. It starts in Section 2 with an overview, partly from a historical insider perspective, of the hosting-capacity approach. This part also includes a discussion on different kinds of uncertainly. A hosting-capacity-based planning approach is presented in Section 3, applied in Section 4.1 through Section 4.6 and discussed in Section 4.7. The description and the application are for overvoltage and undervoltage as these are the phenomena, with the possible exception of overcurrent, for which the best calculation tools, performance indices and limits are available. The third part of the paper contains a detailed discussion about including other phenomena in hosting-capacity studies. For each phenomenon, performance indices, limits and calculation methods are discussed. Hosting CapacityThe term "hosting capacity" was coined in the context of distributed generation by André Even in March 2004 during discussions within the integrated European EU-DEEP project [23,24]. An approach for quantifying the hosting capacity was developed further by others within that same project [25]. The term "hosting capa...

PV Hosting Capacity Dependence on Harmonic Voltage Distortion in Low-Voltage Grids: Model Validation with Experimental Data

“…The voltage rise due to harmonic injection is analyzed and discussed with the aim of validating the discussed model and also putting forward recommendations for connecting PV generation across other network systems.Energies 2018, 11, 465 2 of 13 currents. Depending on the DER connection point and network characteristics of the electrical network system, voltage distortion caused by harmonic current injection may, or may not, reduce the system hosting capacity beyond the limits imposed by the maximum rise of the fundamental voltage component [4][5][6].The impact of DG can be quantified using a set of power indicators. The nature of the impact depends on the characteristics of the network system itself [5][6][7][8][9][10][11][12][13][14][15][16][17][18].…”

“…For these occurrences, the impact on voltage quality must be studied as well as the impact of emission by other equipment connected to the grid, where this part of the planning should cover a combination of measurements, simulation studies and relevant information about the grid [6,10-21]. Furthermore, capacity limitation, which is derived from the hosting capacity, is a function of the consequent impact on power quality, such as the voltage rise and background harmonic voltage, among others.According to [6], many studies have been done on the impact of local generation on the grid, where overcurrent and overvoltage, for example, are the capacity limitations most commonly studied to date. In other words, a large scale of active power electronics, either in production or consumption, can result in further phenomena, the interharmonics or supraharmonics cited above.…”

“…Another aspect has also been considered in current studies: the amount of capacitance connected to the grid that is expected to increase at all voltage levels in the grid, which takes further analysis in order to preclude the impacts on the power quality of the distribution grid. As we can see, [6] shows us an overview of the power quality issues which is related to major challenges in this field. This aspect is detailed in the following section and gives the validity and scope to the present work.This paper is divided into three main parts.…”

“…Energies 2018, 11, 465 2 of 13 currents. Depending on the DER connection point and network characteristics of the electrical network system, voltage distortion caused by harmonic current injection may, or may not, reduce the system hosting capacity beyond the limits imposed by the maximum rise of the fundamental voltage component [4][5][6].…”

“…The impact of DG can be quantified using a set of power indicators. The nature of the impact depends on the characteristics of the network system itself [5][6][7][8][9][10][11][12][13][14][15][16][17][18]. For PV systems, a feeder's PV hosting capacity may be defined as the largest PV generation which can be integrated without violating the limits of these feeders to which it is connected.…”