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All Journal ELPOSYS: Jurnal Sistem Kelistrikan
Rachmat Sutjipto
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Control & Systems Engineering Electrical & Electronics Engineering Energy Engineering Industrial & Manufacturing Engineering

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Analisis Penggunaan Transformator Sisipan Untuk Mengatasi Rugi Tegangan dan Pembebanan Lebih Rachmat Sutjipto; Heri Sungkowo; Epiwardi; Dhimas Dhesah Kharisma
Elposys: Jurnal Sistem Kelistrikan Vol. 10 No. 3 (2023): ELPOSYS vol. 10 no. 3 (2023)
Publisher : Politeknik Negeri Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33795/elposys.v10i3.4223

Abstract

On the JD267 distribution transformer with a capacity of 100 kVA at the Kalibaru feeder on the PT PLN (Persero) ULP Genteng experienced overloading at WBP (88.03%) and high voltage losses. The magnitude of the load exceeds 80% of the standard transformer capacity and is in the bad category (load >= 80%) according to Table I. SE No. 0017.E/DIR/2014, related to transformer loading percentage. Meanwhile, the voltage loss of the JD267 transformer when the WBP is in Phase R is 19.05%, Phase S is 17.08%, and Phase T is 18.33%. This exceeds the voltage tolerance limit in SPLN 1:1995 that the voltage is not allowed to exceed +5% and -10% of the PLN standard voltage, namely 220 V. To handle this problem, PT. PLN (Persero) ULP Genteng carried out the installation of insert transformers by estimating load growth in the next 5 years using the Least Square method. After the addition of the insert transformer, the loading on the JD267 distribution transformer fell to 58.93% on WBP. Meanwhile, the magnitude of the JD267 transformer voltage loss when the WBP after insertion in the R Phase decreases to 0.84%, the S Phase is 1.04%, and the T Phase is 1.63%, and when the LWBP after insertion in the R Phase decreases to 0 .76%, S Phase 0.30%, and T Phase 0.6%. Based on the data above, adding an insert transformer can improve the loading percentage on the transformer and reduce voltage losses that occur at the end voltage of the transformer.
Analisis Kondisi Isolasi Pada Station Service Transformer (SST) Rachmat Sutjipto; Harrij Mukti K; Kharisma Eka Dzulfiqar
Elposys: Jurnal Sistem Kelistrikan Vol. 11 No. 2 (2024): ELPOSYS vol. 11 no. 2 (2024)
Publisher : Politeknik Negeri Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33795/elposys.v11i2.5186

Abstract

There is an identified oil leak in SST Unit 1 at Paiton Power Plant, discovered after a fault indicator in Central Control Room. Visual inspection revealed that the gasket seal on the fastening bolts was damaged due to the seal reaching its lifetime limit. Continuous oil leaks degrade the transformer's oil, reducing its volume and impairing the transformer's cooling performance. The research aims to evaluate the insulation condition of the SST transformer before and after replacing the damaged gasket seal (repacking). This evaluation ensures the transformer's optimal performance and reliability by preventing potential failures caused by degraded insulation. The research employs a quantitative approach, using various tests to assess the insulation resistance of the transformer, including the Polarization Index (PI), Tangent Delta, and Breakdown Voltage tests. Data were collected from technical assessments and measurements conducted on-site at PT. PLN Nusantara Power (PLN NP). The comparison of data before and after repacking indicated significant improvements in the insulation condition of the SST transformer. All test results—PI, Tangent Delta, and Breakdown Voltage—met the standards post-repacking, showing better performance than before. Specifically, the Polarization Index and Tangent Delta values improved substantially, aligning with the IEEE C57.152-2013 standard, and the Breakdown Voltage met the IEC 60156-95 standard. The findings suggest that timely maintenance, such as gasket seal replacement, is crucial for maintaining the insulation quality and overall performance of transformers. Regular inspections and adherence to testing standards can prevent operational failures and extend the lifespan of critical electrical equipment.
Efektivitas Mutasi Transformator Dalam Mengatasi Fluktuasi Beban Pada Trafo Distribusi ULP Bululawang Harrij Mukti K.; Rachmat Sutjipto; Vidiasih
Elposys: Jurnal Sistem Kelistrikan Vol. 11 No. 2 (2024): ELPOSYS vol. 11 no. 2 (2024)
Publisher : Politeknik Negeri Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33795/elposys.v11i2.5187

Abstract

Transformer is a very important component in the distribution of electricity from the distribution substation to consumers. Overloading and underloading of transformers can lead to significant inefficiencies and increased losses in the electrical distribution system. Based on data measurement of the ULP Bululawang transformer in 2022, it was found that the C0177 transformer (100 KVA) was overloaded (88.4%) and the C0254 transformer (160 KVA) was underloaded (21.4%). Load forecasting for 2027 predicts that the C0177 transformer load will reach 107%, causing overheating, while the C0254 transformer will remain underloaded at 23.68%. To address these issues, a transformer mutation was proposed. This study aims to evaluate the effectiveness of transformer mutation in redistributing loads and improving efficiency. The method involved measuring transformer loads before and after mutation and using the Least Square method for load forecasting. Post-mutation measurements showed the C0177 transformer load reduced to 62.6% and the C0254 transformer load increased to 37%. These results indicate that the transformer mutation significantly balanced the load distribution. The study also adjusted the protection settings, including FCO, output cable, main switch, PHB-TR, and NH Fuse output cable. The findings suggest that transformer mutation can effectively address load imbalances, improve operational efficiency, and reduce power losses in the distribution system.
Implementasi Least Square Method Dalam Evaluasi Hasil Uprating Transformator Distribusi Rachmat Sutjipto; Sungkowo, Heri; Khristiana , Harrij Mukti; Kharisma , Dhimas Dhesah; Galang Putra Fauzy; Faradina Agiesta Anjali
Elposys: Jurnal Sistem Kelistrikan Vol. 12 No. 1 (2025): ELPOSYS vol. 12 no. 1 (2025)
Publisher : Politeknik Negeri Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33795/elposys.v12i1.6450

Abstract

Overloading in distribution transformers negatively affects operational reliability, efficiency, and equipment lifespan. At Gardu Distribusi C0058 PT PLN (Persero) ULP Bululawang, the transformer with a 160 kVA capacity exceeded the safe loading threshold of 80%, reaching 92.2% in the first semester of 2022 and 90.1% in the second semester of 2022. This study aimed to analyze the effectiveness of the uprating method as a solution to mitigate overloading issues while ensuring long-term transformer performance. The research employed quantitative analysis with direct measurement, load factor evaluation, and load forecasting using the Least Square method. Before the uprating process, the transformer experienced a peak load of 147.55 kVA (91.7%), significantly surpassing the recommended safety limits. The uprating process increased the transformer capacity from 160 kVA to 200 kVA, reducing the loading percentage to 73.57%, which brought it back within the acceptable operational range. Furthermore, load forecasting using the Least Square method predicted that the transformer would remain within a safe load level, reaching 79.73% in 2027, ensuring stability for the next five years. These findings align with previous studies emphasizing the effectiveness of transformer uprating as an alternative to relocation or additional transformer installation. However, further research is required to evaluate the impact on protective devices and system reliability. This study highlights the viability of uprating as an efficient and cost-effective strategy for managing transformer overloading in distribution networks.
Evaluasi Operasional Pemutus Tenaga Gas SF6 di Gardu Induk 150 kV Rachmat Sutjipto; Heri Sungkowo; Muhammad Khairan; Slamet Nurhadi; Muhammad Fahmi Hakim
Elposys: Jurnal Sistem Kelistrikan Vol. 12 No. 1 (2025): ELPOSYS vol. 12 no. 1 (2025)
Publisher : Politeknik Negeri Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33795/elposys.v12i1.6847

Abstract

Circuit Breaker (CB) is a critical component in high-voltage substations that functions to switch and disconnect electrical currents under normal and fault conditions. Over time, operational aging and environmental factors may degrade the performance of CB, potentially impacting power system reliability. This study aimed to evaluate the feasibility of 150 kV CB at Probolinggo Substation, particularly in Transformer Bay 1 and Transformer Bay 3, through a comparative analysis of insulation resistance, contact resistance, contact simultaneity, and SF6 gas purity based on tests conducted in 2021 and 2023. The study employed experimental methods and standard-based evaluations, referring to VDE (Catalogue 228/4), IEC 60694, SKDIR-0520/2014, and CIGRE standards. The findings revealed that although insulation resistance values showed slight degradation in 2023, they remained above the minimum threshold, ensuring safe operation. Contact resistance increased marginally due to dust accumulation and aging but still met the IEC 60694 standard. Contact simultaneity remained well within SKDIR-0520/2014 limits, indicating proper switching operation. SF6 gas purity tests showed a minor increase in moisture content due to condensation, yet all parameters complied with CIGRE standards. These results align with previous studies that highlight CB degradation over time but confirm that regular maintenance can sustain its operational reliability. This research underscores the importance of periodic monitoring and predictive maintenance strategies. Future work should explore real-time IoT-based monitoring and numerical simulations to enhance failure prediction models and optimize maintenance strategies for high-voltage circuit breakers.
Co-Authors Dhimas Dhesah Kharisma Epiwardi Faradina Agiesta Anjali Galang Putra Fauzy Harrij Mukti K Harrij Mukti K. Kharisma , Dhimas Dhesah Kharisma Eka Dzulfiqar Khristiana , Harrij Mukti Muhammad Fahmi Hakim Muhammad Khairan Slamet Nurhadi Sungkowo, Heri Vidiasih