PRZEGLĄD ELEKTROTECHNICZNY, ISSN 0033-2097, R. 97 NR 6/2021 113 Ikhlas KITTA 1 , Salama MANJANG 1 , Ida RACHMANIAR 1 , Wahyu SANTOSO 1 , Makmur SAINI 2 Hasanuddin University (1), State Polytechnic of Ujung Pandang (2), Indonesia doi:10.15199/48.2021.06.21 Mini Hydro Power Plant connected to 20 kV network as a replacement of Diesel Power Plant Abstract. Renewable energy power plants such as Mini Hydro Power Plants are currently being developed in Indonesia to fulfill electrical energy. Generally, the location of the Mini Hydro Power Plant (MHPP) far from the load center, and it requires a long electricity network so it is necessary to know the optimal position when connecting to a 20 kV distribution system. The technical and economic approach is carried out on the interconnection of the MHPP to the 20 kV distribution system. One thing that needs to be added to the selection of connection point locations is the environmental criteria that are intended to reduce GHG emissions by reducing the use of oil-fired plants such as Diesel Power Plants. Because sometimes the decision to choose the location of the generator connection point is technically and economically more optimal than other locations, but from an environmental perspective it is less than optimal compared to other locations. As explained in the decision making of the Rongkong MHPP which is directly connected to Masamba which can reduce the power capacity of the Cakaruddu Diesel Power Plant (Diesel-PP) maximally, even though the connection investment costs are more expensive than the closest location to the Diesel-PP. Streszczenie. W Indonezji trwają prace nad budową elektrowni wykorzystujących energię odnawialną, takich jak mini elektrownie wodne, które mają dostarczać energię elektryczną. Generalnie lokalizacja Mini-Elektrowni Wodnej (MHPP) z dala od centrum obciążenia wymaga długiej sieci elektroenergetycznej, dlatego konieczna jest znajomość optymalnego położenia przy podłączaniu do systemu dystrybucyjnego 20 kV. Do wyboru lokalizacji przyłącza należy dodać kryteria środowiskowe, które mają na celu redukcję emisji gazów cieplarnianych poprzez ograniczenie wykorzystania elektrowni opalanych olejem, takich jak elektrownie Diesla. Czasami decyzja o wyborze lokalizacji punktu przyłączenia generatora jest technicznie i ekonomicznie bardziej optymalna niż inne lokalizacje, ale z punktu widzenia ochrony środowiska jest mniej niż optymalna w porównaniu z innymi lokalizacjami. Jak wyjaśniono w procesie decyzyjnym Rongkong MHPP, który jest bezpośrednio połączony z Masamba, co może maksymalnie zmniejszyć moc elektrowni Diesla Cakaruddu (Diesel-PP), mimo że koszty inwestycji w przyłączenie są wyższe niż lokalizacja najbliższa Diesel-PP. (Mini elektrownia wodna dołączona do sieci 20 kV jako alternatywa dla generatora Diesla) Keywords: Renewable energy, Mini Hydro Power Plant, 20 kV distribution system Słowa kluczowe: Energia odnawialna, Mini Elektrownia Wodna, dystrybucja 20 kV 1. Introduction Energy plays an important role in humans, especially in modern life like today, humans cannot live without energy [1]. Human activity is highly dependent on the availability of energy for various purposes, namely transportation, electricity, household needs, and the needs of Mini and macro industries. Energy is very broad when viewed from its source, the most common of which is fossil energy in the form of oil, natural gas, and coal but recently there are new and renewable energies. In 2015, Indonesia's need for 166 MTOE fulfilled its needs by using petroleum (oil) as the main source. Fig. 1 concerning Indonesia's National Energy Mix in 2015 shows that new and renewable energy (NRE) has been used as much as 5% of the total national energy mix [2]. The installed capacity of the Renewable Energy power plant in 2015 was recorded at 8215 MW of the total potential of 443208 MW, in other words, only 1.9% of the total potential of Renewable Energy in Indonesia has been successfully utilized. Fig. 1. Indonesial energy mix in 2015 With reference of National Energy Policy (NEP) as stipulated in the Government Regulation of the Republic of Indonesia No.79 of 2014, the realization of the use of Renewable Energy in the national energy mix is targeted to reach 23% in 2025 and 31.2% in 2050. Hydropower is a very large potential source of renewable energy, but the utilization is still far below its potential. The potential for hydropower in the South Sulawesi area (one of the provinces in Indonesia located on the island of Sulawesi) is estimated at around 3709 MW [3]. Renewable energy power plants in the form of Mini Hydro Power Plant (MHPP) are generally located in suburban areas far from the load center [4]. To make use of it, the Mini hydro power plant is interconnected in the electricity system, especially in the 20 kV electric power distribution system. Long distances will result in reduced power that reaches the load due to power losses. When connecting the MHPP to the 20 kV power distribution system, it will have a positive and negative impact on technical and economic parameters [5]. There are several kinds of sources of electrical energy supply in the distribution network, namely: (a) a network whose source is directly supplied from Substation, (b) there is a system supplied by a substation and a conventional energy power plant in the form of a Diesel Power Plant (Diesel-PP), (c) there are those from substations and renewable energy power plants such as Mini Hydro Power Plants, (d) and those supplied from substations and a mixture of Renewable Energy (MHPP) and conventional power plants (Diesel-PP). One of the objectives of developing a renewable energy power plant in the form of a MHPP is to reduce energy consumption from petroleum, where this petroleum energy will produce carbon dioxide (CO 2 ) which has an impact on the increase in emissions of the Greenhouse Gasses (GHG) [6]. Therefore, in this paper, it is explained how the interconnection process of a MHPP in a 20 kV distribution system which is supplied from the Grid, MHPP and Diesel- PP. This interconnection study is approached technically, economically, and environmentally. An environmental approach is carried out by reducing as much as possible the power capacity of the Diesel Power Plant when the MHPP is connected to the system.