Brochure · EN — Siemens Energy brochure for the Power VT, an inductive voltage transformer for high-voltage substations whose improved winding design also lets it act as on-site high-voltage test equipment for the GIS primary system. It keeps all standard VT values (type-tested to IEC 61869-1 and IEC 60044-2, rated voltage up to 170 kV, voltage factor 1.9 for 8 h, accuracy class 0.2 at 100 VA / class 0.5 at 200 VA, measuring frequency 50/60 Hz) and adds high-voltage testing per IEC 62271-203 table 107 at test frequency 100 Hz ± 20 % over a test section of up to 2 bays. The brochure lists the operational benefits of testing without external test sets, the field record (working in GIS substations for more than 8 years, approx. 200 units in operation in 32 countries, no incidents, also available for SF6-free blue GIS substations), and single-line examples of optimal Power VT placement in six GIS busbar arrangements. No detailed per-rating technical table is included in this document.
Inductive voltage transformers (VT) are an essential part of high-voltage substations whether air- or gas insulated. They are typically used to provide measuring signals for control, protection and metering systems and thus ensure the reliability of the switchgear. With an improved design of the windings, the Power VT becomes your high-voltage test equipment, which then allows for standard high-voltage tests of the primary system.
With the Power VT you can rely on all standard values of every common voltage transformer:
Type-tested according to IEC 61869-1 and IEC 60044-2.
Rated voltage up to 170 kV.
Voltage factor 1.9 for 8 h.
Accuracy: class 0.2 at 100 VA, class 0.5 at 200 VA.
Measuring frequency 50/60 Hz.
The brochure states these headline values only; it contains no detailed per-rating technical data table.
With the Power VT you can benefit from additional functions compared to a standard component:
High-voltage testing according to IEC standards and proposed test levels at your site (IEC 62271-203 table 107).
Test frequency 100 Hz ± 20 %.
Test section up to 2 bays.
A simplified diagram shows the test set-up: a control & feeding unit (diagram labels: CPC 100, CP TR1, CP CR1; 90 Hz – 120 Hz) feeding the Power VT installed in the GIS.
Test preparation within minutes allows re-testing at any time over the whole life cycle, e.g. after GIS extension, reassembling or extensive service activities, quality and performance tests.
GIS operation can start directly after the test without mechanical work on the primary circuit and removing the high-voltage test set.
No extra space needed for temporary installation of huge high-voltage testing facilities.
Low investments in site-based testing facilities.
Stay independent as tests can be conducted by any neutral testing company worldwide.
No need of large container with high-voltage test equipment.
Small and lightweight testing equipment can be transported as carry-on luggage.
Standard socket can be used as power supply (e.g. 3-phase, 400 V, 20 A).
High-voltage tests are as easy as testing a protection relay.
Our Power VTs are working in GIS substations for more than 8 years.
Approx. 200 Power VTs are currently in operation, in 32 countries worldwide, with no incidents.
Also available for blue GIS® substations (SF6-free) — no SF6-gas handling at site is needed for test preparation.
The brochure shows single-line diagrams of where to place a Power VT instead of a standard VT for six typical GIS configurations: single busbar (>5) with busbar section analyzer, double busbar (>5) with busbar section analyzer, cable in the middle, ring arrangements, H arrangements, and 1 ½ circuit-breaker arrangements.
Click any figure to enlarge.