The contracts were co-signed by AG Investments and Dongfang Electric International Corporation.
The projects cost around US$30 million (K98m) and fall under the Town Electrification Investment Program Tranche 2 Project funded by the Asian Development Bank (ADB).
PPL acting managing director, Carolyn Blacklock, said the maintenance works were crucial to ensure PNG achieves its targets of less-cost power generation.
She said while there are many discussions on other forms of power generation, what they should focus on is rehabilitating existing assets.