Abstract
This study investigates the impact of Time-of-Use (TOU) scheduling and battery energy storage
systems (BESS) on voltage stability in a typical Malaysian medium-voltage distribution
network with high photovoltaic (PV) system penetration. The analyzed network comprises
110 nodes connected via eight feeders to a pair of 132/11 kV, 15 MVA transformers, supplying
a total load of 20.006 MVA. Each node is integrated with a 100 kW PV system, enabling
up to 100% PV penetration scenarios. A hybrid mitigation strategy combining TOU-based
load shifting and BESS was implemented to address voltage violations occurring, particularly
during low-load night hours. Dynamic simulations using DIgSILENT PowerFactory
were conducted under worst-case (no load and peak load) conditions. The novelty of this
research is the use of real rural network data to validate a hybrid BESS–TOU strategy, supported
by detailed sensitivity analysis across PV penetration levels. This provides practical
voltage stabilization insights not shown in earlier studies. Results show that at 100% PV
penetration, TOU or BESS alone are insufficient to fully mitigate voltage drops. However,
a hybrid application of 0.4 MWh BESS with 20% TOU load shifting eliminates voltage
violations across all nodes, raising the minimum voltage from 0.924 p.u. to 0.951 p.u. while
reducing active power losses and grid dependency. A sensitivity analysis further reveals
that a 60% PV penetration can be supported reliably using only 0.4 MWh of BESS and 10%
TOU. Beyond this, hybrid mitigation becomes essential to maintain stability. The proposed
solution demonstrates a scalable approach to enable large-scale PV integration in dense
rural grids and addresses the specific operational characteristics of Malaysian networks,
which differ from commonly studied IEEE test systems. This work fills a critical research
gap by using real local data to propose and validate practical voltage mitigation strategies.