Metal-oxide surge arresters for gas-insulated systems, Phases I and II. Final report
The development of metal-oxide surge arresters for gas-insulated systems is described. The arrester is contained in SF/sub 6/ gas in an aluminum enclosure which is designed to connect directly to a port in a gas-insulated substation. Special MOV blocks were produced for operation in SF/sub 6/. A technique was developed for soldering these blocks together for strength and simplicity in assembly. Special care is taken so that the soldered blocks are not affected by high-energy discharges. Three, 362kV prototype arresters were assembled, each using three parallel columns of these soldered 50-mm blocks. The electrical length of each column is 2330 mm. This MOV assembly is centered within a 660 mm (26'') diameter by 3451 mm long aluminum tank. Uniform grading along the MOV column is achieved by a series of ceramic capacitors which are connected along the column. This prototype was designed on the basis of results from three types of analytical studies. First, a heat-transfer model was developed to predict the temperature of the MOV blocks for various operating voltages, currents, and ambient temperatures. A thermal mock-up was assembled to verify this heat-transfer model and provide empirical coefficients. Second, electric-field derivations were carried out to ensure that electric stresses would be kept below 4kV (rms)/mm. Finally, an electric-circuit-equivalent model was prepared to derive the values for the grading capacitors. Continuous testing for 72 h at a-c voltage in the range of 209 to 285kV confirmed the predicted operation and thermal stability of this prototype design. The behavior of this arrester in typical power-systems applications are shown by computer calculations for lightning surges and switching operations. The expected effects of seismic activity and internal fault arcs are also derived. Basic characteristics of gas-insulated metal-oxide arresters for 69, 138, 230 and 500kV were also derived.
- Research Organization:
- Brown Boveri Electric, Inc., Chalfont, PA (USA)
- OSTI ID:
- 6394584
- Report Number(s):
- EPRI-EL-2876; ON: DE83901849
- Resource Relation:
- Other Information: Portions are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GAS-INSULATED SUBSTATIONS
LIGHTNING ARRESTERS
DESIGN
PERFORMANCE
EHV AC SYSTEMS
EXPERIMENTAL DATA
HVAC SYSTEMS
SEMICONDUCTOR RESISTORS
SULFUR FLUORIDES
SURGES
AC SYSTEMS
DATA
ELECTRICAL EQUIPMENT
ENERGY SYSTEMS
EQUIPMENT
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
INFORMATION
NUMERICAL DATA
POWER SUBSTATIONS
POWER SYSTEMS
RESISTORS
SEMICONDUCTOR DEVICES
SULFUR COMPOUNDS
200301* - Power Transmission & Distribution- AC Systems
EHV & UHV- (-1989)