NOJA Power News

Issue 13

OSM Recloser Interface Test Set

The implementation of testing procedures is an integral aspect of both the switchgear manufacturing and servicing processes. Possessing the ability to conduct testing both in house and on the field ensures the safety, lifespan and rated operation of switchgear devices.

Due to the large range of primary fault currents (up to 16000A), relays are generally tested using secondary injection, whereby the relays are subjected to the same currents they would normally receive from the secondary of a CT. However, unlike general protection relays, the OSM recloser does not provide discrete inputs for CT connections, making it difficult to introduce a secondary signal to the MPM. Furthermore, the recloser utilises Rogowski sensors within the cubicle instead of CT's, which output a voltage signal proportional to the input current. This does not allow for a current signal to be injected into the MPM.

NOJA Power Interface Test Set

To overcome this problem, NOJA Power provides an Test Set to simulate the current and voltage signals generated by sensors inside the OSM15 and OSM27 recloser bushing.
The Interface Test Set uses Rogowski transformers to convert an injected current signal into the voltage signal that the MPM is expecting. When used in conjunction with a power system and three phase test set it can be used to conduct the following tests:

Three phase short circuit
Phase to phase short circuit
Earth fault
Upstream broken wire
Low source voltage
Loss of supply

In addition to this functionality, this device has external voltage free contacts both normally open and normally closed that simulate the positioning of the contacts. The simulator also allows coil faults to be actioned and include; Mechanical Trip / Manual Trip, Simulator Coil Short Circuit, Simulator Coil Open Circuit.

The Interface Test Set allows for either the OSM or Simulator to be selected for coil operation from the MPM. This offers several advantages during application. As the MPM provides directional protection using voltage as a reference to determine current directions, the Interface Test Set provides an interface so that LV can be applied that the MPM will interpret as MV to allow for directional testing. This also provides the means to test UV1, Uv2 and UV3 based protection.

NOJA Power Awarded for Exporting Success

In 2002, NOJA Power made its first ever sale of medium-voltage reclosing switchgear to China, a country renowned for embracing new technologies.

In just five years NOJA Power has developed markets on every continent on Earth, an impressive feat that has earned the company the title of Queensland Exporter of the Year at the 2007 Premier of Queensland Export Awards. 2007 also saw NOJA Power awarded with the Latin American Business Award and the British Chamber of Commerce Export Award.

Managing Director Neil O'Sullivan describes the company as being “born global”, and that the key to NOJA Power's exporting success is the development of a product suitable for the global market rather than any single market.

While Australia traditionally sees itself as a country built on mining exports, Neil states that high-tech innovations offer the same massive export potential.

“We realised early on that our world-first technologies, which increase the reliability of electricity supply, had many global applications so it was always our intention to sell overseas as well as domestically,” he said.

“Our export business has established channels to market in 70 countries and we currently supply switchgear products to 46 of them”.

Highly skilled staff and an ongoing commitment to research and development ensure the success of NOJA Power's cutting-edge product range in the worldwide marketplace.

Where other switchgear manufacturers utilise the insulation properties of the environmentally harmful gas SF6, NOJA Power Switchgear remains SF6 free by utilising solid dielectric technology. NOJA Power also holds the patent on the arc fault contained and vented vessel to create a safe and environmentally friendly product.

Since the company was established, their number of employees has grown ten-fold.

“Because of our cutting edge technology, we tend to attract high performers who seek challenges and job satisfaction beyond the monetary rewards ”.

“We offer apprenticeships and traineeships that lead into engineering degrees and our employees can then take on more senior roles,” Neil said.

The NOJA Power Switchgear team at the 2007 Queensland Export Awards

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