Medium Voltage Uninterruptible Power Supply

ABB developed its first medium-voltage power protection system to help meet the needs of a growing number of potential customers with sensitive or critical loads.

The company’s PCS100 MV uninterruptable power supply was developed at the company’s power conditioning centre for excellence in Napier.

ABB says the growing size of semi-conductor factories and data centres makes medium-voltage protection systems a better option for those clients.

Not only can the units provide complete facility protection, but they have a world-class efficiency level of 99.5 per cent as lower current at medium voltage results in lower losses.

ABB says they are also cheaper and simpler to operate, and easier to install and maintain. Their physical location is more flexible, meaning they can be placed in MV electrical rooms or plant substations. That in turn frees up space for more important customer infrastructure such as servers or manufacturing tools.

ABB says the company had to translate the concepts behind its low-voltage offline UPS systems to medium-voltage and upscale it in power. The company’s previous limit had been 480 V AC.

The change also required the up-skilling of its engineering workforce for MV. The company also drew on expertise from Christchurch-based power electronics specialists ELMG and Roger McKenzie of R2B2 Engineering.

ABB says the main development was a three-phase switch of 6 MVA at 6.6 kV, capable of being turned off in two milliseconds. The switch had a powerful digital signal processing (DSP)-based controller, firing 18 silicon controlled rectifiers. The SCR stacks were provided by ABB Lenzburg in Switzerland.

ABB says it placed huge emphasis on reliability and robustness and many of its fail-safe features were developed in-house.

But the modularity that ensures availability and reliability also increased the complexity of the product’s coordination and control system. The 6 MVA machine contains 50 DSP processors, which ABB says was an extensive software engineering exercise.

Operating a medium-voltage test environment was also a new challenge for the Napier operation, given the access restrictions and onerous energisation and de-energisation protocols required, and the resulting time that took.

ABB initially targeted the Japanese market and has so far sold 20 MW of medium voltage UPS. It is also looking to develop 10 kV, 11kV and 15 kV products for UK-influenced markets, China and the US respectively.

The expanding internet-of-things will also likely require greater digitisation and connectivity of the units in the future.

ABB says the global market size for the MV UPS is USD$350 million a year and growing strongly.  Given the entire value chain is based in New Zealand, the product’s success is growing ABB’s business in New Zealand with positive benefits for employment and local suppliers.

The Energy Technology of the Year award category is sponsored by Callaghan Innovation