Infokum Vol.
No.
03, 2026, pp.
ISSN 2722-4635
Analysis of the Effect of Transformer Load Balancing on the Reduction Technical Shrinkages in Distribution Substations aAt Feeders JN 05 At PT PLN (PERSERO) ULP JANARATA Ivan Kristiawan Zega1 .
Dino Erivianto2 .
Muhammad Erpandi Dalimunthe3 Universitas Pembangunan Panca Budi.
Medan.
North Sumatera.
Indonesia Email: 1ivanzega978@gmail.
com, 2derivianto@gmail.
com, 3erpandi@dosen.
Electricity is a vital component in supporting activities across various sectors, particularly in industry.
The reliability of the power distribution system is crucial to maintaining the continuity of energy supply.
However, during the distribution process, power losses .
echnical losse.
frequently occur, primarily due to load imbalance in distribution This study aims to analyze transformer loading on the JN 05 feeder at ULP Janarata by calculating the load percentage, phase current imbalance, and power losses caused by neutral current.
A quantitative approach was used, based on field measurements of 16 transformers under Peak Load Conditions (WBP) and Off-Peak Load Conditions (LWBP).
Prior to load balancing, total power losses due to neutral current reached 10,190.
37 kWh during LWBP and 3,733.
41 kWh during WBP each month.
After load balancing was performed between phases, technical losses were reduced by 13,923.
77 kWh per month.
These results indicate that load balancing is an effective method to reduce power losses and improve the efficiency of the distribution system.
Keywords: Transformer load imbalance.
Neutral current, and Transformer losses.
This is an open access article under theCC BYNClicense Corresponding Author:
Ivan Kristiawan Zega Universitas Pembangunan Panca Budi.
Medan.
North Sumatera.
Indonesia 1ivanzega978@gmail.
Introduction Electrical energy is a primary need to support various human activities, including industrial, commercial, and residential sectors.
In its distribution process, electrical energy goes through several stages, from generation to transmission to distribution.
A crucial component in the power distribution system is the distribution transformer, which steps down the voltage from the primary distribution system to the voltage required by end consumers.
However, in practice, distribution transformers often experience interphase load imbalances due to uneven load distribution.
This imbalance causes high neutral currents, increases power losses, accelerates equipment wear, and reduces the efficiency and reliability of the overall electricity distribution system.
Furthermore, load imbalances can also affect the quality of voltage received by customers and potentially cause damage to electrical equipment.
PT.
PLN (Perser.
ULP Janarata is a unit that distributes electricity for Bener Meriah Regency and parts of Central Aceh Regency.
The electrical system at ULP Janarata is supplied by the Takengon Main Substation through two substations: the Janarata Substation and the Lampahan Substation.
These two substations distribute energy to the public through 14 feeders, spanning a 532.
6-kilometer Medium Voltage Network (JTM).
In the distribution of electrical energy at the Janarata ULP, many transformers are unbalanced, necessitating load balancing.
This requires analyzing the effectiveness of transformer load balancing on neutral current reduction and power losses in the distribution system, as well as evaluating its impact on the technical performance of the distribution substations.
The results of this study are expected to contribute to improving the efficiency of the electricity distribution system and support efforts to control technical losses by electricity providers.
Analysis of the Effect of Transformer Load Balancing on the Reduction Technical Shrinkages in Distribution Substations aAt Feeders JN 05 At PT PLN (PERSERO) ULP JANARATA.
Ivan Kristiawan Zega et.
Infokum Vol.
No.
03, 2026, pp.
ISSN 2722-4635
Literature Review A distribution substation is an electrical substation consisting of Medium Voltage Distribution Equipment (PHB-TM).
Distribution Transformers (TD), and Low Voltage Distribution Equipment (PHB-TR) to supply electricity to customers using both Medium Voltage (TM 20 kV) and Low Voltage (TR 220/380V) (PLN Book 4, 2.
A transformer is a static device based on electromagnetic principles, transforming alternating voltage and current between two or more windings at the same frequency and at different voltage and current values.
The main structure of a transformer consists of a primary coil, a secondary coil, and a core.
Voltage is applied to the primary coil, which generates a sinusoidal current.
This current creates a magnetic field in the magnetic core, called flux, which also has a sinusoidal shape.
The secondary coil, subjected to the flux change from the core, which is called induction, generates an Electromotive Force (EMF) that has a sinusoidal shape.
The operating principle of a transformer is based on Ampere's and Faraday's laws, namely, that an electric current can produce a magnetic field, and conversely, a magnetic field can produce an electric current.
If an alternating current is applied to one of the transformer coils, the number of magnetic lines of force changes, resulting in induction on the primary side.
The secondary side receives a varying number of magnetic lines of force from the primary Induction also occurs on the secondary side, resulting in a voltage difference between the two A three-phase system is a common method used to transmit electrical power.
A three-phase system can use a neutral wire or a neutral wire, more commonly known as a three-phase four- wire system with a neutral wire and a three-phase three-wire system without a neutral wire.
Low-voltage distribution networks in Indonesia generally use a three-phase four-wire system.
Figure 1.
Normal 3-Phase System Waveform with RST Sequence A 20 kV distribution transformer consisting of primary and secondary coils has varying voltage-tocurrent and voltage-to-output ratios based on the capacity of each transformer.
Differences in transformer capacity will affect the primary .
and secondary .
current values.
Figure 2.
Single Line Diagram of a 20 kV Distribution Substation The transformer capacity is used based on customer consumption needs, as per each consumer's power contract requirements.
The transformer capacity is used based on customer consumption needs, as per each consumer's power contract requirements.
Analysis of the Effect of Transformer Load Balancing on the Reduction Technical Shrinkages in Distribution Substations aAt Feeders JN 05 At PT PLN (PERSERO) ULP JANARATA.
Ivan Kristiawan Zega et.
Infokum Vol.
No.
03, 2026, pp.
ISSN 2722-4635
Table 1.
20 kV Distribution Transformer Capacity Data Voltage Capacity Current Primary (V) Secondary (V) Primary (A) Secondary (A) Method The object of this research is the Distribution Substation at the JN 05 (City Rout.
feeder of ULP Janarata PT PLN (Perser.
Figure 3.
Single Line Diagram of the JN 05 ULP Janarata Feeder The approach used in this research is descriptive because the data is measured and calculated directly, in the form of information expressed in numbers or numerical forms collected quantitatively.
The stages begin with a literature review, which involves searching, collecting, and studying theorems that support the solution to the research problem.
These theorems were obtained from scientific journals, previous research results, and reference books.
Data collection was then conducted through field surveys and measurements using an ampere meter.
From the collected data, mathematical calculations were performed to determine the percentage of load unbalance, the percentage of loading, the percentage of neutral current, and the neutral conductor power loss in the transformer before and after repairs.
Results and Discussion Analysis Transformer.
Transformer Load Unbalance Calculation Analysis Before Repair From the results of mains current measurements (R.
T, and N) conducted under WBP conditions .
:00 AM to 2:00 PM WIB) and LWBP conditions .
:00 PM to 9:00 AM WIB), using the formula:
Analysis of the Effect of Transformer Load Balancing on the Reduction Technical Shrinkages in Distribution Substations aAt Feeders JN 05 At PT PLN (PERSERO) ULP JANARATA.
Ivan Kristiawan Zega et.
Infokum Vol.
No.
03, 2026, pp.
ISSN 2722-4635
%Load Unbalance={.
}/3 x 100% The transformer load imbalance percentage is as follows:
Table 2.
Transformer Load Unbalance Percentage under LWBP Condition Kapasita
Arus
Arus
Arus
Arus
Ketidaks Trafo
Induk R Induk S Induk
Induk
Kode Gardu
VA) (A) (A) T (A) N (A) Beban (%) BAN 001
BAN 002
BAN 003
BAN 004
BAN 005
BAN 006
BAN 007
BAN 008
BAN 009
BAN 010
BAN 011
BAN 025
BAN 026
BAN 027
BAN 028
BAN 034
Table 3.
Percentage of transformer load imbalance in WBP conditions Arus Arus Arus Arus KetidakKapasitas Induk R Induk S Induk T Induk N Kode Gardu Trafo .
VA) (A) (A) (A) (A) Beban (%) BAN 001
BAN 002
BAN 003
BAN 004
BAN 005
BAN 006
BAN 007
BAN 008
BAN 009
BAN 010
BAN 011
BAN 025
BAN 026
BAN 027
BAN 028
BAN 034
Based on the results of measurements carried out before load balancing, the conditions of each substation were obtained as follows when compared with SE:NO:17:14.
Analysis of the Effect of Transformer Load Balancing on the Reduction Technical Shrinkages in Distribution Substations aAt Feeders JN 05 At PT PLN (PERSERO) ULP JANARATA.
Ivan Kristiawan Zega et.
Infokum Vol.
No.
03, 2026, pp.
ISSN 2722-4635
Baik Cukup Kurang Buruk Baik Cukup Kurang Buruk Kondisi Ketidakseimbangan Beban Gardu Distribusi Penyulang JN 05-WBP Kondisi Ketidakseimbangan Beban Gardu Distribusi Penyulang JN 05-LWBP Analysis of Transformer Load Unbalance Calculations after Repair After determining the load imbalance values at each JN 05 feeder distribution substation, load balancing was performed at each unbalanced substation by moving the house line cables from the high phase to the low phase to achieve interphase balance.
Table 4.
Implementation of SR Cable Transfer
Nama Realisasi Pemindahan SR
Gardu R ke S (A) R ke T (A) S ke R (A) S ke T (A) T ke R (A) T ke S (A) BAN 001
BAN 002
BAN 003
BAN 004
BAN 005
BAN 006
BAN 007
BAN 008
BAN 009
BAN 010
BAN 011
BAN 025
BAN 026
BAN 027
BAN 028
BAN 034
The following are the load values for each phase and the percentage of unbalance between phases for each substation under both WBP and LWBP conditions.
Table 5.
Percentage of Transformer Load Unbalance under LWBP Conditions Kapasit
Arus
Arus
Arus
Arus
Ketidakas Trafo Induk R
Induk
Induk
Induk
Kode Gardu
VA) (A) S (A) T (A) N (A) Beban (%) BAN 001
BAN 002
BAN 003
BAN 004
BAN 005
BAN 006
BAN 007
Analysis of the Effect of Transformer Load Balancing on the Reduction Technical Shrinkages in Distribution Substations aAt Feeders JN 05 At PT PLN (PERSERO) ULP JANARATA.
Ivan Kristiawan Zega et.
Infokum Vol.
No.
03, 2026, pp.
BAN 008
BAN 009
BAN 010
BAN 011
BAN 025
BAN 026
BAN 027
BAN 028
BAN 034
ISSN 2722-4635
Table 6.
Percentage of transformer load imbalance in WBP conditions Kapasit
Arus
Arus
Arus
Arus
Ketidakas Trafo Induk R
Induk
Induk
Induk
Kode Gardu
VA) (A) S (A) T (A) N (A) Beban (%) BAN 001
BAN 002
BAN 003
BAN 004
BAN 005
BAN 006
BAN 007
BAN 008
BAN 009
BAN 010
BAN 011
BAN 025
BAN 026
BAN 027
BAN 028
BAN 034
Analysis of Transformer Load Unbalance Percentage Before & After Repairs The load balancing activities carried out have had a positive percentage of transformer load imbalance in the JN 05 feeder.
on reducing the Figure 4.
Percentage of Transformer Load Unbalance in WBP condition before and after repair Analysis of the Effect of Transformer Load Balancing on the Reduction Technical Shrinkages in Distribution Substations aAt Feeders JN 05 At PT PLN (PERSERO) ULP JANARATA.
Ivan Kristiawan Zega et.
Infokum Vol.
No.
03, 2026, pp.
ISSN 2722-4635
Figure 5.
Percentage of Transformer Load Unbalance in LWBP condition before and after repair Analysis of the Effect of Transformer Load Balancing on Neutral Current The reduction in load imbalance on the JN 05 feeder transformer also resulted in a decrease in the neutral current in the neutral conductor.
The magnitude of the neutral current reduction can be seen in the following graph.
Figure 6.
The value of the neutral current in the WBP condition before and after repairs Figure 7.
The value of the neutral current in LWBP conditions before and after repairs Analysis of the Effect of Transformer Load Balancing on the Reduction Technical Shrinkages in Distribution Substations aAt Feeders JN 05 At PT PLN (PERSERO) ULP JANARATA.
Ivan Kristiawan Zega et.
Infokum Vol.
No.
03, 2026, pp.
ISSN 2722-4635
Analysis of Losses in Neutral Conductors Caused by the Emergence of Neutral Current before and after Figure 8.
Power loss due to neutral current before and after load balancing From the load balancing activity, the reduction in neutral current also had a significant impact on reducing losses or saving kWh by 13,923.
77 kWh.
Converted to Rupiah using the average kWh tariff of the Janarata ULP, it is:
Savings = 13,923.
77 kWh x Rp 628.
11/kWh = Rp 8,745,662.
00/month Conclusion Based on the previously analyzed data, it can be concluded that:
The power losses caused by the current flowing in the neutral conductor of the JN 05 feeder transformer on the LWBP before balancing were 16,369.
8 kWh, while on the WBP it was 6,459.
21 kWh.
The power losses caused by the current flowing in the neutral conductor of the JN 05 feeder transformer on the LWBP after balancing were 6,179.
43 kWh, while on the WBP it was 2,725.
kWh.
From these improvement activities, the total kWh savings achieved were 13,923.
77 kWh/month, or Rp 8,745,662.
00/month.
References