For more than 80 years, Siemens has been testing electro-technical equipment in high and medium voltage at its test facilities at the Schaltwerk Berlin, Germany. In this exclusive interaction with T&D India, we have Dr. Lars Klingbeil, Head of High Voltage Research and Development Test Fields, Siemens, telling us more on the Schaltwerk Berlin lab with respect to switchgear. Dr Klingbeil is confident that Siemens, thanks to its continuous monitoring of trends in power engineering, can derive new requirements for the future of switchgear testing.
What are the different types of switchgear that can be tested at the Siemens Berlin laboratory?
The research and development test fields at Berlin Schaltwerk can test a wide range of switchgear, from low- and medium-voltage up to the ultra high-voltage range.
We offer almost every test possible for switchgear and other high-voltage equipment from 36 kV to 1,100 kV. The majority of our test objects are in fact switchgear, both air- and gas-insulated. These include all varieties of one- and three-phase types and those with different insulation gases and various housing materials, from traditional porcelain and composite housings to fully metal-enclosed systems.
What are the different tests that can be performed on switchgear at the lab? [Please also explain in brief the significance of important tests]
temperature rise and environmental test labs.
At the High Power Lab we test devices like surge arrester, disconnectors, grounding switches, current and voltage transformers, and busbar systems.
We perform all kinds of type and development tests including basic short-circuit tests, short-time withstand current and peak withstand current tests, capacitive current switching tests, and surge arrestor tests with pre-stress.
In the High Voltage Lab facility, all types of dielectricIn general, our test fields consist of three labs: High Power, High Voltage, and Mechanical, including tests are conducted, such as impulse voltage, AC and DC voltage, and partial discharge measurements in shielded halls.
The Mechanical Lab covers mechanical endurance tests, temperature rise tests, and various kinds of environmental tests.
What are the international standards to which tests at the Berlin lab conform?
The scope of our accreditation encompasses not less than 118 international standards, most of them IEC but also IEEE, GB, GOST, and others. Because we focus on switching technology, most of our tests refer to the IEC 62271-family and parts relevant to circuit breakers (-100), disconnecting and grounding switches (-102), and gas-insulated switchgear (-203).
The Berlin Lab also conforms to the most common standards for other equipment like surge arresters, insulators, and instrument transformers.
The majority of our customers are Siemens R&D departments and production facilities. We offer our services to external customers too.
What are some of the recent advances in switchgear testing at the Berlin lab?
I could mention many, but these are the most important:
A four-parameter transient recovery voltage (TRV) with alternating recovery voltage up to 1,100 kV was added, along with special test circuits for three-phase testing of vacuum circuit breakers. This will allow us to perform synthetic testing of circuit breakers for higher system voltages.
In the High Voltage Lab, the superposition test has been elaborated and improved to include very high voltages in order to superimpose DC stress with impulse voltages. This is critical for HVDC transmission solutions.
And last but not least, the temperature rise lab was recently upgraded to a capability of 10,000 A, both 50 and 60 Hz AC as well as DC!
Does the Berlin lab cater only to Siemens’ internal testing requirement, or does it serve other manufacturers?
The majority of our customers are Siemens R&D departments and production facilities. We offer our services to external customers too: We’ve already served customers from Brazil to Russia and Iceland to India. Some were switchgear manufacturers, but most of our external customers need their instrument transformers, surge arresters, dividers, capacitors, machines tested.
We understand that Siemens recently launched a new medium-voltage SF6-free switchgear. Was this type-tested at the Berlin lab? Did it require specialized testing?
We didn’t test this model at the Berlin facilities. All the required tests were performed at the independent PEHLA test laboratory at Schaltanlagenwerk Frankfurt, Germany. Like all medium-voltage switchgear, the blue Siemens 8DAB 12 was tested according to the relevant IEC standards. In addition to these mandatory tests, the colleagues over there gave special attention to tests that would ensure a maintenance-free lifespan, which is standard for SF6 high technology.
Power transmission is moving toward extra- and ultra-high voltages. In general, how is switching matching up to the requirements? What implications does high-voltage switchgear have for testing?
Of course, those voltage levels increase the demands placed on the test labs. We’re in a good position to be able to do AC testing in our large open-air test field.
With respect to high power testing, the situation is somewhat easier because unit-tests are possible. That means that we can adhere to the standards for half-pole and even quarter-pole tests.
What plans does Siemens have to expand the Berlin lab for switchgear testing?
We’re continuously monitoring the trends in power engineering so we can derive new requirements for the future of switchgear testing. In the short and mid-term, we’re concentrating on a variety of measures to prepare the test labs to work with all kinds of SF6-free equipment. This covers alternative gases for insulation and arc-quenching to vacuum-breaker technologies for high-voltage applications, starting at the lower system voltage levels and stepping up to higher levels.
