Voltage stability analysis: Case study in Madura 150 kV transmission system

Voltage stability problem during the operation of the power system cause serious failures in the power system, so that making the development of stability analysis an important necessity. In this study, the data taken were Gilitimur, Bangkalan, Sampang, Pamekasan and Sumenep bus obtained from PT. PLN (Persero) UP2B East Java Madura 150 kV system area. In March 2019 there was a large voltage drop on the Sumenep bus so that the voltage was 133 kV. In power systems, the system voltage must be maintained within the limits (+ 5%) and (-10%) of the nominal voltage. Based on these regulations, the voltage condition on the Sumenep load bus experiences a voltage drop of 17 kV or >10% so that the voltage drop has exceeded the allowable voltage standard, whereas on other buses in Madura the region has also experienced a voltage drop that is almost close to the standard limit as in the Sampang bus has a voltage drop of 137 kV. To predict the voltage stability of the system in Madura, it can be done with a voltage stability analysis study using the Q-V Sensivity Analysis method. This analysis can be useful to determine which buses are prioritized for maintenance. In the Q-V Sensivity Analysis it is assumed that the bus voltage and load is absolute, when the value of Jacobian reduction (JR) is negative, indicating that the bus condition is unstable. In the analysis of the Sumenep bus the negative value is -0.015 while the other buses are positive namely the Gilitimur bus = 1.225, Bangkalan bus = 0.502, Sampang bus = 0.448 and Pamekasan bus = 0.287, so it can be concluded that the 150 kV Madura transmission system has unstable buses is the Sumenep bus