The ABB High Power Laboratory in Ludvika, Sweden, currently tests virtually all of their power products. This international industrial group tests things like switchgear, high voltage circuit breakers and transformers at various stages during product development and as part of routine testing of the finished products.The tests involve subjecting the products to extreme current and voltage stresses, then acquiring the test data at an extremely high sampling rate. Advanced test and measuring equipment is used, including the HBM Genesis HighSpeed measuring system combined with Perception software. Ludvika has been at the heart of ABB's testing activities for power products since 1933, when it housed what was at the time the largest short-circuit generator in the world. To this day, Ludvika remains a world leader in this highly specialized field. The site has two robust short-circuit generators capable of delivering a combined power of 4,000 MVA for direct testing. For synthetic testing, they can supply as much as 75,000 MVA.
"We work with extremely high currents and voltages. Many of our tests are also destructive, meaning there is not much left of the products after testing. And you obviously can't test high voltage products without a few fireworks. Even so, the test needs to work so that everything that happens in an instant is documented perfectly. We want to see an accurate, detailed curve describing the process," says Kjell Korhonen, senior engineer and specialist in measuring technology and control systems at ABB's High Power Laboratory in Ludvika.
The extreme stresses and high sampling rates (up to 100 mega samples per second) are clearly very challenging for the tools used. Back in the 1980s, ABB was already pioneering the design of digital test data systems. This early work formed the basis of what today has become a commercial product – the HBM Genesis HighSpeed family for transient logging of data. ABB still works closely with HBM as it develops the system, now in its ninth generation. "It's important to us that the system is still being developed by a commercial enterprise with a large number of other users, and that we can access support and updates. We now use Genesis and Perception in all our labs, and we have a healthy dialog with HBM with regard to improvements. It's reassuring to have a uniform and effective set of tools that are constantly being updated," adds Kjell Korhonen.
The laboratory has access to four measuring racks of the Genesis HighSpeed system. The system is flexible because the required modules can be plugged directly into the rack. For large-scale tests, multiple measuring racks can be combined. Each measuring rack has space for a receiver card with four channels each. Fiber optic cables link the channels to digitizers, which convert the signal from analog to digital and pass it on to the Perception software for verification and processing. The laboratory and the test equipment at Ludvika are operated in two shifts with around 30 highly qualified engineers.
Virtually all ABB power products are tested at various stages during product development and also in routine testing of the finished products. On average, this means two high frequency tests per day, all year round. A test can take anywhere from a couple of hours to a week, generating as much as 1,000 megabytes of data. ABB retains this data for at least ten years. All tests are carried out in accordance with international and regional standards, and the laboratory itself is subject to independent quality inspections by Swedish accreditation authority Swedac. Membership of the Scandinavian Association for Testing of Electric Power Equipment (SATS) and its international umbrella organization Short-Circuit Testing Liaison (STL) is a further mark of quality. All work must be strictly in accordance with the standards; otherwise, the equipment undergoing type testing in the laboratory cannot be certified.
Continuity is crucial in our work. We need to think about thousands of things that can potentially go wrong in a test – cabling, bugs, and positions of measuring equipment. We often only get one chance to test a product, and the whole thing is over in a matter of seconds. We simply cannot afford to lose data. For this reason, our years of experience are a major asset and we work hard to recruit the right skills and to train our employees, who come to Ludvika from all over the world.
The ABB High Power Laboratory is not exactly risk free. High currents and voltages can knock out the system, and in a worst-case scenario, sensitive components – such as the sensors used to measure network quantities like current, voltage, pressure or motion, and the digitizers that convert the signals – can burn out and require replacement. The four measuring racks for the Genesis HighSpeed system have a long service life due to the unique electrical isolation. Fiber optic links are used to connect the measuring racks in the control room to digitizers, protecting the racks as well as the personnel from high voltages.
"To stay in front, we constantly have to update our equipment to reflect the latest technology, and it's a real challenge when the time comes to switch to the next generation of measuring system. We are under constant pressure to improve measuring accuracy. We are also trying our best to grow – in terms of volume and our ability to test more objects in new ways. We'll always need to measure quantities like current and voltage, but new tests will be added in future. For example, one day we might want to measure motion in a contactless process," predicts Kjell Korhonen
Genesis HighSpeed is a system for rapid test data acquisition. The Genesis HighSpeed family can handle sampling frequencies up to 100 mega samples per second per channel on multiple channels. Because the system is based on a modular platform, the system can be configured for the particular application. The Perception software is designed to process large volumes of data quickly and reliably. With Perception, 10 gigabytes of data can be viewed on a PC in 10 seconds.