Voltage Control with PV Inverters in Low Voltage Networks—In Depth Analysis of Different Concepts and Parameterization Criteria

Bletterie, Benoît; Kadam, Serdar; Bolgaryn, Roman; Zegers, Antony

doi:10.1109/tpwrs.2016.2554099

Cited by 92 publications

(42 citation statements)

References 19 publications

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“…Usually, an assumption is used such that, from the network nodes’ point of view, the knowledge of the uncertainty of one PV output is similar to the knowledge of the neighboring PV. In other words, PVs installed on different buses are modeled to inject power according to the same probability density functions (PDFs) . The same may apply for random variables of loads wherein, for one feeder, load profiles may share the same characteristics, following the behaviors of dwellers .…”

Section: Introductionmentioning

confidence: 99%

New risk analysis considering spatial correlations among connected PVs for bidirectional distribution feeders

Al‐Saadi

Živanović

Al-Sarawi

2020

Int Trans Electr Energ Syst

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Summary The distribution networks are in a transition stage from being “passive” (consuming energy and typically with unidirectional power flows) into “active” (consuming/producing energy with bidirectional power flows). This transition has exposed the networks to stochastically behaving risks such as violation of the prescribed limits of power quality or overloading the network elements. The current paper presents a new risk analysis to quantify the risks of violating operational constraints due to a large number of small‐size Photovoltaics (PVs). Risk's likelihood and severity are estimated based on the relative frequency of the number and the relative frequency of the accumulative depth of a violation, respectively. This article has two objectives. The first is to determine the hosting capacity of the targeted network. The second is to address the effect of spatial correlation on risk quantification, specifically the effect of perfectly positive correlation (PEC) to the effect of partially positive correlation (PAC). Modelling PAC through spatial rank correlation is established utilizing the Nataf transformation due to the non‐Gaussianity of the probability densities of PV uncertainties. The approach is implemented on two distribution networks: IEEE 13 bus test distribution feeder and a large distribution network with multiple zones situated in South Australia. The approach is location‐specific and time‐varying. Hosting capacity is determined with the results of PEC showed an overestimation of the problem in comparison with the more realistic simulation under PAC. The analysis outcomes can help distribution network operators in managing and regulating the growing risks of high PV penetration.

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Section: Introductionmentioning

confidence: 99%

New risk analysis considering spatial correlations among connected PVs for bidirectional distribution feeders

Al‐Saadi

Živanović

Al-Sarawi

2020

Int Trans Electr Energ Syst

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“…Local cosϕ(P)-and Q(U)-control of PV-inverters [13,14,17,22,23] are often used for voltage control in LV grids. As an alternative, references [19][20][21] propose to install inductive devices equipped with local L(U)-control close to the end of the violated LV feeders.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Local Volt/var Control Strategies for PV Hosting Capacity Enhancement of Low Voltage Feeders

Schultis¹

2019

Energies

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The PV hosting capacity of low voltage feeders is restricted by voltage and current limits, and in many cases, voltage limit violations are the limiting factor for photovoltaic integration. To control the voltage, local Volt/var control strategies absorb or inject reactive power, provoking an additional current. This study analyzes the hosting capacity increase potential and the associated additional grid losses of local cosφ(P)- and Q(U)-control of photovoltaic inverters, and of local L(U)-control of inductive devices and its combination with Q-Autarkic prosumers. Therefore, four theoretical and one real low voltage test-feeders with distinct structures are considered: long overhead line, short overhead line, long cable, short cable and branched cable. While the theoretical test-feeders host homogeneously distributed PV-plants, the real one hosts heterogeneously distributed PV-plants. Each test-feeder is used to conduct load flow simulations in the presence of no-control and the different control strategies separately, while gradually increasing the PV-penetration. The minimum PV-penetration that provokes voltage or current limit violations is compared for the different control strategies and test-feeders. Simulation results of the theoretical test-feeders show that the hosting capacity increase potential of all local Volt/var control strategies is higher for the overhead line feeders than for the cable ones. Local L(U)-control, especially its combination with Q-Autarkic prosumers, increases the hosting capacity of all low voltage test-feeders significantly. The PV-inverter-based local Volt/var control strategies, i.e., Q(U)- and cosφ(P)-control, enable lower hosting capacity increases; in particular, cosφ(P)-control causes high additional currents, allowing the feeder to host only a relatively small PV-module rating per prosumer. Q(U)- and cosφ(P)-control are not sufficient to increase the hosting capacity of the long cable feeder significantly; they provoke high additional grid losses for the overhead line test-feeders. Meanwhile, L(U)-control, especially its combination with Q-Autarkic prosumers, increases the hosting capacity of the long cable feeder significantly, causing high additional grid losses during peak production of PV-plants. Regarding the real test-feeder with heterogeneously distributed PV-plants, on the one hand, the same trend concerning the HC increase prevails for the real branched cable test-feeder as for the theoretical short cable one. On the other hand, higher losses occur for the branched feeder in the case of L(U)-control and its combination with Q-Autarkic prosumers, due to the lower voltage set-points that have to be used for the inductive devices. All in all, the use of local L(U)-control, whether combined with Q-Autarkic prosumers or not, enables the effective and complete utilization of the existing radial low voltage feeders.

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“…The latter can be set by remote control, i.e., online presetting of target values, or by schedules [13]. The set value may be a constant power factor [12][13][14][15][16][17], constant reactive power [12][13][14]16,17], constant voltage at a given bus [13,18], Q(U) characteristic [11,[14][15][16][17][18][19][20][21][22][23], or cosϕ(P) characteristic [12,14,16,17,[21][22][23]. P and Q are the active and reactive power provided by inverter; cosϕ is the power factor set at inverter level; U is the voltage of the feeder bus where the inverter is connected.…”

Section: Introductionmentioning

confidence: 99%

Effectiveness of Distributed vs. Concentrated Volt/Var Local Control Strategies in Low-Voltage Grids

2018

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This paper introduces a novel local Volt/var control strategy in a low-voltage smart grid. Nowadays, various Volt/var local control strategies built on customer photovoltaic inverters, e.g., cosφ(P) and Q(U), are introduced to mitigate the upper voltage limit violations in feeders with high prosumer share. Nevertheless, although these strategies are further refined by including more local variables, their use is still very limited. In this study, the effects of a new concentrated Volt/var local control strategy in low-voltage grids are investigated. Concentrated var-sinks, e.g., coils-L(U), are set at the end of each violated feeder. The concentrated local control strategy L(U) is compared with the distributed cosφ(P) and Q(U) strategies. Initially, both control strategies are theoretically investigated, followed by simulations in a test feeder. Finally, the expected practical significance of the findings is verified through simulations in a real typical urban and rural grid. Additionally, the impact of the different local control strategies used in low-voltage grids on the behavior of the medium-voltage grid is analyzed. The results show that the concentrated Volt/var control strategy eliminates the violation of upper voltage limit even in longer feeders, where both distributed local strategies fail. In addition, the concentrated L(U) local control causes less reactive power exchange on the distribution transformer level than the distributed cosφ(P) and Q(U) strategies. Therefore, the reactive power exchange with the medium-voltage grid and thus the distribution transformer loading are smaller in the case of concentrated local control strategy.

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Voltage Control with PV Inverters in Low Voltage Networks—In Depth Analysis of Different Concepts and Parameterization Criteria

Cited by 92 publications

References 19 publications

New risk analysis considering spatial correlations among connected PVs for bidirectional distribution feeders

New risk analysis considering spatial correlations among connected PVs for bidirectional distribution feeders

Comparison of Local Volt/var Control Strategies for PV Hosting Capacity Enhancement of Low Voltage Feeders

Effectiveness of Distributed vs. Concentrated Volt/Var Local Control Strategies in Low-Voltage Grids

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