TEKNOSAINS: Jurnal Sains, Teknologi dan Informatika
Vol 13 No 1 (2026): TEKNOSAINS: Jurnal Sains, Teknologi dan Informatika

Technical evaluation of kVar import anomalies on main transformer number 2 at Siman Hydroelectric

Mohamad Farel Firmansyah (Universitas Negeri Malang, Indonesia, 65145)
Arya Kusumawardana (Universitas Negeri Malang, Indonesia, 65145)
Royb Fatkhur Rizal (Universitas Negeri Malang, Indonesia, 65145)
Soraya Norma Mustika (Universitas Negeri Malang, Indonesia, 65145)
Hafidz Malkanz Chaironi (Universitas Negeri Malang, Indonesia, 65145)
Ruth Nike Dauhan (Universitas Negeri Malang, Indonesia, 65145)



Article Info

Publish Date
31 Jan 2026

Abstract

An issue of reactive power import (negative kVar) was identified in Main Transformer No. 2 at PLTA Siman, resulting from mismatched voltage ratios and impedance values among parallel-operated transformers. This mismatch induced a circulating current and led to reactive power being absorbed from the external grid, increasing energy losses and operational costs. This study aims to investigate the root cause of the anomaly, propose technical solutions, and evaluate their effectiveness. The analysis was conducted out through system simulation using ETAP software, testing three technical scenarios: installation of a 569.9 kVar capacitor bank, implementation of a Standard Operating Procedure (SOP) for PMT disconnection during standby conditions, and replacement of the transformer with one that matches the specifications of the other units. The simulation results revealed that SOP implementation eliminated kVar import by 100% during standby, the capacitor bank reduced it by approximately 70%, and transformer replacement fully eliminated the circulating current. The findings suggest that a combined approach involving SOP and capacitor installation offers an optimal solution without major infrastructure replacement.

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Journal Info

Abbrev

tekno

Publisher

Subject

Description

Aim and Scope Aim The aim of this journal publication is to disseminate the fundamental ideas or ideas that have been accomplished and the study findings in technology, science and informatics. In terms of community sector study outcomes, the Journal of Technoscience primarily reports on the main ...