HVDC GREEN: HVDC GRid for intErconnEcting Nusantara

Project summary

Indonesia electricity demand is to increase 76% in the next 10 years. As of today, the majority of electricity consumption is in Java, where the majority of people (56%) and industry locates. Currently, 69.5% of the energy in Java already comes from coal-fired power plants. Indonesia should reduce the use of coal due to negative impacts on local environment and health such as: CO2 emission, decrease in fish catches and agricultural yields, and premature deaths. One way is to use renewable energy sources (RES). However, Java has limited space and resources, while other islands have large potential (up to 209 GW) and low demand. HVDC-VSC technology has the ability to transmit large amounts of power with high degree of flexibility and reliability. In the Indonesian context, the technology shows very high potential, because it can transmit large quantities of power between electrical islands and over wide water bodies. HVDC links would allow transmitting carbon-neutral power from islands where its generation is more efficient and viable to those with high consumption, while improving the grid reliability by increasing the level of interconnection.

However, existing HVDC links connect to strong AC grids (grids with high generation/consumption and well interconnected) or to generation islands, as offshore wind farms. Island grids in Indonesia with good potential for RES are weak grids and existing HVDC control strategies will underperform or not operate. To implement an HVDC link in these conditions requires a radical new approach. To adapt existing techniques is not enough. It is necessary to research new control principles for implementing this technological solution in Indonesia.

This leads to the project main research question: How to implement an efficient and reliable HVDC technology connecting the main Indonesia islands, when accounting the low grid strength, for allowing the replacement of coal generation by RES in Indonesia?

Outputs

Midterm report
A strong Indonesian grid over a large geographic area is required to integrate wind, solar and other renewable energy sources. HVDC links would allow transmitting carbon-neutral power from islands where its generation is more efficient and viable to those with high consumption. However, the weak electrical strength of the many islands poses a serious challenge to the implementation of the technology and new innovative solutions are required. To support the use of HVDC in Indonesia, the HVDC GREEN project has the following objectives:
1.To research a novel DC secondary control capable of operating when connected to weak AC grids.
2.To design a methodology to reinforce the islanded HVAC grids and to optimise the location of HVDC links so that large amounts of power can be transmitted via the DC links, without leading to grid instability.
3.To research a control strategy for taping into AC areas with lower power production or consumption.

So far, the project has developed detailed simulation of several Indonesian islands, it studied the stability limits for the weak islands when connected to a HVDC link and developed a new DC/DC converter solution for DC tapping. Different control algorithms are being implements, tested and adapted for operating in very weak grids.
A dozen of related bachelor and master projects have been supervised. Two scientific papers were accepted for a IEEE flagship conference (POWERTECH) and two journal papers are under review at IEEE and CIGRE.