Bushing Refurbishment Service

Circuit Breaker / Voltage Transformer / Current Transformer / Transformers

Background

High Voltage Solution (HVS) undertakes specialist high voltage On Line Partial Discharge & asset management services, to the Australian & New Zealand HV industry. HVS has identified an industry problem & provides asolution to aging HV bushings which fail resulting in expensive outages leading to complete replacement ofthe asset concerned. (CB, CT, VT & transformers). HVS has teamed up with a highly respected UK companycalled ALW (www.alwgroup.co.uk) to undertake refurbishment / replacement of bushing ranging up to 132kV.

Problems

The primary function of a high voltage bushing (HVB) is to conduct high voltage from the bus connection through the outer steel frame to the inside of the high voltage CB, CT, VT & transformer.Degradation of gasket sealing components, conductor insulation, or porcelain insulator cracking can lead to HVB failure affecting reliability and availability. Deterioration of these critical components is a process directly related to operational service conditions. Once a key HVB component has failed, it is difficult to repairtions

Options

By undertaking an in service Partial Discharge survey using specialised equipment which identifies the asset at risk we would recommend to the client to removal the asset from service or if this is not possible place a restriction of entry into the switch yard. Once removed, the asset can be replaced with from critical spares the client holds (After these spares have been tested for their integrity prior to being placed into service) If no spares are available, then ALW Services via High Voltage Solution offers several options to provide the most reduced cycle time to return the failed asset back into service, such as providing a new or a complete refurbishment of the existing bushing.

Service You Expect (Complete bushing disassembly)

• Assessment & evaluation of all components
• Replace all gasket seals with Viton
• Inspection / Replacement (if required) of porcelain insulator
• Cleaning of all components to 'as new' condition
• Silver plating connection ends
• Reassembly
• Electrical testing including Hi Pot and Doble
• Pressure testing or tests as required by the client

The ability to replace porcelain insulators particularly distinguishes ALW from its competition. Most vendors have abandoned the use of ceramic materials and have substituted composite material.

ALW Bushing Services Experience

• 15 day cycle on refurbished bushings
• 30 day turnaround on new bushings
• Significant cycle reduction on replacement HVB with available stock
• Ability to restore both standard and non-standard OEM

Refurbishment cost is much less than the purchase of new bushings. Refurbishment provides an opportunity to upgrade bushing components. Turn around time can often be much less than waiting for a new bushing, we may already have the exact bushing you need in our finished inventory.