STARON 25–500 kV — OIP Transformer Condenser Bushings, Porcelain and Composite Insulator (IEEE Standard)

STARON — taking up the challenge

Siemens Energy offers an extensive range of high voltage products, fully complying with the IEEE market requirements. Together with STAROIP, which provides the unique feature of a stainless-steel bellow as oil expansion chamber, STARON completes the offer with a conventional IEEE design, providing an oil sight glass to allow the regular check operations.

STARON is the enhanced generation of Siemens Energy OIP (Oil Impregnated Paper) condenser bushing, with voltage ratings between 25 and 500 kV, specifically designed to meet IEEE market requirements, with an optimized design based on the conventional IEEE standards. The portfolio is designed following the high-quality standards of Siemens Energy and provides increased grid safety thanks to the electrical and thermal margins included in the design and type tests performed beyond IEEE Standard requirements.

The cutaway diagram on page 2 labels the six main components: 1 Terminal, 2 Oil filling, 3 Insulator, 4 Active part, 5 Flange, 6 Oil-side end.

Standards

The STARON series complies with world-wide international standards and has been specifically designed and tested according to IEEE C57.19.01-2017 and IEEE C57.19.00-2004.

The STARON portfolio meets all applicable dimensional requirements of the IEEE Standard C57.19.01-2017, allowing interchangeability with your installed base.

Design and insulating oil

The fine capacitance graded core is wound onto the winding support inserting aluminum foils to control the electrical field both radially and axially. The head and flange consist of a weather resistant aluminum alloy. All O-ring seals are in a self-contained chamber and are made of temperature resistant elastomers.

The bushing is filled with mineral oil as a part of the insulation. The oil used in STARON bushings has a very low affinity of solubilizing copper, therefore the copper migration phenomenon into the insulation is avoided.

Design characteristics

Air side insulator: porcelain cemented into the flange for increased cantilever withstand capability; the design is available with porcelain and composite insulators. The oil side epoxy insulator provides high impact resistance and reduced size. An embedded end shield in the epoxy insulator eliminates external shielding in draw lead applications up to 230 kV and provides greater internal clearances.

Horizontal transportation and storage is possible. Draw lead adapters allow replacement of old draw lead bushings without modification of the existing stud & cable.

Standard creepage distance of 44 mm/kV (heavy pollution) USCD as per IEEE C57.19.100-2012, with 54 mm/kV (extra heavy pollution) available for ratings up to 230 kV.

Installation altitude: standard 1.000 m (3.300 ft), design available on request up to 3.000 m (10.000 ft) — thousands separators as printed in the source.

Oil sight glass or magnetic oil level options are available to allow the standard maintenance checks.

Seismic: high performance level acc. to IEEE 693-2018, based on composite insulator design — 161 kV to 500 kV: reports based on comparable shake table test performed; below 161 kV: qualified by static pull test or inherently acceptable.

STARON — your benefits

Maximum reliability due to special design, rigorous testing and use of proven materials. More robust electrical design validated by highest requirements of IEEE and IEC standards.

Syphon design (a feature inside the bushing head) allows storage and installation in different positions. High interchangeability with existing IEEE designs makes them suitable for many retrofitting cases. Qualified for optional ambient temperature down to -60°C.

Large variety of bottom terminals

Bottom terminals according to IEEE Std. C57.19.01-2017 are shown as dimension drawings: Fig. 2.4 (Ø 9/16" holes ×2), Fig. 2.5 (Ø 9/16" holes ×4, 1¾" spacing), a threaded part (dimensions according to table), Fig. 3.4, and Figs. 3.5 and 3.6 (R4", Ø 8¼", ½"-13 (×8), ¾" DEEP (6.75" BCD) holes).

Additional terminals are available: a draw-lead design with embedded shield, and a removable split conductor with 4 fixing screws and threaded part (dimensions according to drawing), rated 1200 A.

Taps designed for different requirements

Test tap: STARON IEEE bushings rated 69 kV and below are provided with a test tap. This tap is usually grounded and is intended for measurement of power factor, capacitance from conductor to tap, as well as offering the possibility to connect to an on-line monitoring system. Since the capacitance from tap to ground is not controlled, the tap is not intended for use as a voltage divider during normal operation.

Voltage tap: bushings with rated voltage starting from 115 kV and above are provided with a voltage tap as required by IEEE Std. C57.19.01-2017. Under normal operation the tap cover is installed and the tap is grounded. When opening the cap, it's possible to connect the bushing to a monitoring device.

Oil sampling plug: the oil sampling valve is available on all voltage levels at the flange position. The plug allows all maintenance operations to be performed as described in the instruction manual.

Rigorous testing and conductor types

The STARON condenser bushing with OIP active part is tested with stringent requirements: type test performed as per IEEE C57.19.00-2004, with electrical test levels at the highest electrical values between IEEE and IEC Standards (IEC 60137-2017).

Depending on the current rating, STARON is provided with different conductor and connection designs. Draw-lead conductor: when the rated current is relatively low, a dedicated connection to the internal draw-lead bolt is provided; the draw-lead can be customized with adapters to facilitate interchangeability with an existing bushing to be replaced. Removable conductor: delivered for medium current ratings, it provides the possibility to install the lower part directly in the transformer turret, facilitating installation. Fixed conductor: when higher current capability is required; the bottom terminal is made out of copper and according to IEEE dimensions.

Electrical characteristics

Full electrical characteristics table for all 34 STARON bushing styles, transcribed verbatim from page 6. The brochure notes: dimensions listed in this document are for general reference and may be subject to change — for specific dimensions, refer to the outline drawing.

Fidelity notes: cell values are transcribed as printed, including '13.38(340)' and '84.645(2150)' without a space in the 1200 A rows; the three 345 kV maximum-altitude cells carry colored revision highlights in the source PDF (values transcribed as printed).

Mechanical characteristics

Full mechanical characteristics table for all 34 STARON bushing styles, transcribed verbatim from page 7. Footnote: *Oil length without bottom connection.

Fidelity notes: terminal thread notations are transcribed as printed, including the mixed '×'/'x' multiplication signs (e.g. '1.5-12UNF-2A x 2' in some 1200 A rows); the Q value for STARON 1675-500-2000 E23 is printed '24 (584.2)' while the sibling -800 and -3000 rows read '23 (584.2)' — transcribed as printed. Several cells and the Bottom terminal / Top terminal / Flange bolt holes column headers carry colored revision-highlight and comment-bubble annotations in the source PDF; values are transcribed as printed.

Type designation

The brochure explains the STARON product designation using the example STARON 150-25-800 E21: the first number is the lightning impulse voltage 1.2/50 μs (kV), the second is the system voltage (kV), the third is the rated current (A), and the final element is the CT pocket length (in) — E21 corresponding to the 21 in (534 mm) CT pocket and E23 to the 23 in (584 mm) CT pocket listed in the mechanical table.

Publisher

Published by Siemens Energy Global GmbH & Co. KG, Transmission, Freyeslebenstr. 1, 91058 Erlangen, Germany; for the U.S. published by Siemens Energy, Inc, Transmission, Raleigh, NC, USA. Article No. PTNP-B10018-00-7600. © Siemens Energy, 2021. Siemens Energy is a trademark licensed by Siemens AG. Subject to changes and errors; performance features are binding only when expressly agreed upon in the concluded contract.

Figures & drawings

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