Formulation and Analysis of an Approximate Expression for Voltage Sensitivity in Radial DC Distribution Systems

Abstract

Abstract:Voltage is an important variable that reflects system conditions in DC distribution systems and affects many characteristics of a system. In a DC distribution system, there is a close relationship between the real power and the voltage magnitude, and this is one of major differences from the characteristics of AC distribution systems. One such relationship is expressed as the voltage sensitivity, and an understanding of voltage sensitivity is very useful to describe DC distribution systems. In this paper, a formulation for a novel approximate expression for the voltage sensitivity in a radial DC distribution system is presented. The approximate expression is derived from the power flow equation with some additional assumptions. The results of approximate expression is compared with an exact calculation, and relations between the voltage sensitivity and electrical quantities are analyzed analytically using both the exact form and the approximate voltage sensitivity equation.

Design and evaluation of voltage control techniques by hierarchical coordination of multiple power converters in low-voltage dc distribution systems

“…Then, voltage estimation algorithms are needed for the points that are not monitored in the distribution system. There are previous researches into application of MASbased voltage control for distribution systems [5][6][7]. Especially, references [6] and [7] presents pioneering jobs about the related issue in DC distribution systems.…”

“…There are previous researches into application of MASbased voltage control for distribution systems [5][6][7]. Especially, references [6] and [7] presents pioneering jobs about the related issue in DC distribution systems. However, reference [6] ignored line losses that can be significant in LVDC distribution system.…”

“…However, reference [6] ignored line losses that can be significant in LVDC distribution system. Reference [7] derived simplified voltage sensitivity factors but can be applied only to radial distribution system. In our system, local agents participate to build the Jacobian matrix of the distribution system together.…”

Demonstration Study of Voltage Control of DC Grid Using Energy Management System Based DC Applications

“…Calculated output adjustment value is transferred to the corresponding distributed energy resource as a command, the output is adjusted accordingly, and then the voltage violation in the power system is cleared. Figure 8 shows the entire flow chart of the voltage control algorithm [31][32][33][34][35]. Figure 9 is the configuration diagram of the demonstration site for DC distribution at the Gochang Power Testing Center of KEPCO.…”

Real-Time Coordinated Control of a Grid-VSC and ESSs in a DC Distribution System for Total Power Loss Reduction Considering Variable Droop Using Voltage Sensitivities

“…However, increased numbers of RESs can cause fluctuations in DC voltages that compromise the stabilities of utilities [4], resulting in various problems. For example, an increase in the load current is caused by a decrease in the load voltage, which thus moves away from the optimal point in terms of voltage stability [5]. Furthermore, in the absence of a reserve power margin, large DC voltage fluctuations can reduce the voltage control capacities of photovoltaics or cause disconnection of the wind systems in DC microgrids [6].…”