Voltage Control in Active Distribution Grids: A Review and a New Set-Up Procedure for Local Control Laws

Abstract

Planning, operation and control of active distribution grids by increasing the number of dispersed generators is becoming more important but also more complex. Hence, the importance of controlling the voltage is highlighted in many research papers. Traditionally, in passive distribution networks the voltage rise has been mitigated by network reinforcement. Nowadays, local voltage control, coordinated voltage control and centralized voltage control have been discussed for active networks in research papers. Although all the approaches have been proven to solve the problem of voltage rise in distribution grids, using plenty of sensors to gather huge number of measurement could cause complexity. This paper represents a literature review of different voltage control approaches in active distribution grids and proposes a new procedure to set up a local voltage control law devoted to properly manage the voltage profile (e.g. minimizing losses on MV feeders).

Voltage Control Methodologies in Active Distribution Networks

“…As discussed in Section 3.2., if this reduction in reactive power margins makes it impossible for the ORPF to find a feasible operating point, then the elastic constraints (15) need to allow the relaxation of this limit. For this reason, following a series of preliminary tests, the penalty coefficients c 1, j and c 2,j of objective function (16) were set up to 100 and 300, respectively. Figure 18 shows the results related to the ORPF constraints for the first step of Configuration 1 in variant a, i.e., ORPF 1.1.a.…”

“…Nowadays, the DNs are still managed as passive networks; a limited set of measurements is available at the HV/MV primary Substations level, and some measurements are available for a minor number of DNs at the secondary MV/LV Substations level, while the network is operated mainly through long-term off-line Thus, depending on the SCADA evolution level, various innovative algorithms for the automatic real-time operation of DN can be designed, from the simple, with reduced controllability, to the complex, with maximum controllability. This paper focuses on voltage control algorithms, which can be classified into three main groups [16]: (1) Local Control, which relies on local measurements, (2) Coordinated Control, an evolution of Local Control, working with a base telecommunication system, and (3) Centralized Control, which involves the complete observability and controllability of the DN. The goal of voltage control is not only to mitigate voltage limit violations and, implicitly, to increase Hosting Capacity (HC) for DGs, but it also represents a resource for optimizing the DN according to different objectives, such as system losses reduction or power factor optimization.…”

Feasible Islanding Operation of Electric Networks with Large Penetration of Renewable Energy Sources considering Security Constraints

“…Mathematically, the model shown in Equations (1)-(4) still holds except for the calculation of the regulating energy. Thus, substituting index i with j in Equations (1)-(4) and rewriting Equation (2) as (5), the model is fully described.…”

“…Due to the wide spread of RES in the electric networks, these proposals need to be de-centralized and they generally fall in the field of the so-called smart grids. Recent years have seen a large amount of research being carried out for the normal operation of the electrical networks: papers [1][2][3] and [4,5] are just a few examples for the transmission and distribution levels, respectively. Article [1] shows an optimization procedure to optimally coordinate the DGs at distribution level to fulfill TSO voltage control requirements at the TSO-DSO interface, article [2] proposes a simple, but robust, on-line procedure to mitigate unpredictable congestions, while [3] shows how the RES time-based LS in presence of high penetration of RESs is proposed in [21].…”

Network Coordination, Self-Regulation Mode, and Autonomous Control Space Planning of Microgrid

“…e impact of multi-microgrid high-permeability grid connection on distribution managers not only stays at the physical level such as the traditional trend direction, size changes, and node voltage changes, and the network reconstruction and reactive power optimization caused by it [1][2][3][4]. e solution is not only the optimization goal of the distribution network when multiple grids are connected to the grid and an optimal scheduling algorithm that seeks a global optimal solution [5][6][7].…”