Hey everyone! I'm currently training at an electricity utility in Sri Lanka (LECO), and I've been given a case study regarding voltage problems in distribution networks caused by a surge in rooftop solar installations. The main issue occurs when solar energy production peaks, especially during midday hours, leading to voltage imbalances across phases because many inverters used are older models that can't manage reactive power or Volt/VAR adjustments. My supervisor wants me to explore global methods to tackle this issue. I've found some solutions like using smart inverters, on-load tap changers, battery storage, phase balancing, and advanced control systems, but I'm really looking for the most cost-effective and practical starting point for implementation. What have other countries or utilities done to combat these voltage imbalances due to high solar penetration, and where should I suggest starting? Any experiences or studies would be greatly appreciated!
3 Answers
I think a couple of approaches could work here. First, remote disconnects could be an option, where older inverter users get cut off power until they upgrade to a smart inverter that can modulate output. Alternatively, implementing an energy market could incentivize consumers to self-consume instead of feeding power back to the grid, especially during peak times when power is abundant. It might also be useful to establish dump loads where high electricity users can buy excess energy cheaply and shift their usage to times when there's overflow.
I've noticed imbalances on larger installations too. Often, it's due to phases being out of sync with other loads, and when the solar kicks in, the regulated grid can't adapt quickly enough. Local utilities sometimes work on adjusting regulation settings to manage this better. But generally, it's a tough issue that mainly utilities can resolve, especially if you're working with smart inverters.
From what I’ve seen, capacitors and battery systems could help manage both high and low voltage swings. Grid-scale battery storage is a popular solution. Plus, virtual power plants are becoming a trend, where they can coordinate with consumers' batteries or EVs to balance the excess power. There’s also programs that get utilities to communicate about excessive power generation and incentivize users to consume energy during peak solar production. Check out some info on losing power purchase during negatives prices; it’s become quite the innovation in some regions!
I've heard that some countries are diving into green hydrogen production using those peak energy hours! It's a big investment but there’s a huge potential for those projects.