Increasing Feeder PV Hosting Capacity by Regulating Secondary Circuit Voltages

Abstract

Voltage rise is one of the major concerns that limits the photovoltaic (PV) hosting capacity or the maximum amount of PV generation that a distribution circuit can accommodate. This paper examines the effectiveness of low-voltage distribution static compensators (LV-DSTATCOMs) in increasing the PV hosting capacity of distribution circuits by mitigating voltage rise. Stochastic analysis framework is used to determine the PV hosting capacity while an iterative placement technique is used to identify effective device locations. To provide insights on the optimal device size, number, and control settings, sensitivity analysis is carried out. The results show that, with appropriate size and control settings, installation of few LV-DSTATCOMs in a distribution circuit can significantly increase its PV hosting capacity. For the circuit under consideration, a set of 23 devices has increased the PV hosting capacity from 15% to 100% of the median day time peak load.

Review on the PV Hosting Capacity in Distribution Networks

“…The HC of the shortest feeder (888) turned out to be highest as 132% among the five distribution feeders due to the short feeder length and lowest impedance value in [14]. Similarly, authors in [48] attributed the low value of HC, 15.5% of the peak load, to the length of the feeder despite having a higher voltage class. The base HC (w.r.t Customer PVs) without the employment of OLTC of a real LV UK network (55.3781 • N) of 9.2 km total length has been reported as 40% in [31] as compared to a 30% PV HC [75] in real LV UK network with same geographical location and HC reference.…”

“…Although, the HC value should be higher in case of feeder 1 with lower impedance value but the lower voltage class of feeder 1 resulted in lower HC value validating the HC dependence on voltage classes as well. Two distribution networks in California (36.7783 • N) reported substantially disparate HC values as 132% and 15.5% of peak load in [14] and [48], respectively. The prime reason for such drastic change in the HC of two networks despite similar geographical location is attributed to the feeder lengths.…”

“…The authors of [3,5,9,10,14,24,44,48,[54][55][56][57][58][59][60][61][62][63][64] defined PV HC with reference to the peak load of the feeder as the ratio of the maximum capacity of the PV installation to the maximum load of the feeder. In [65], the authors investigated the HC of a rural European three-phase balanced system for two types of simulations that is one-time slot simulation and time series simulation and an estimated HC of 86% of peak load has been observed.…”

“…This section is concentrated solely on the voltage violations taken as the main limiting factor by the authors and the limits defined as per standards. The HC research conducted in [7,[9][10][11], [41,45,48,53,54,56,66,67,86,87] defined the voltage violation limits complying with ANSI standard. The ANSI limits defined for overvoltage violation, voltage deviation and voltage unbalance are 0.95 p.u.-1.05 p.u., 0.03 p.u.…”

“…The dynamic loading of components alleviates the voltage stability issues resulting from cloud movements especially in case of small geographical areas that are otherwise not handled by static load modeling [41]. Moreover, some HC increasing methods employ ancillary devices for voltage regulation such as inverter PF control [3,44], Smart Inverters [2,45,46], Static Compensators [47,48] and Secondary VAr Controllers (SVCs) [10].…”