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Product category: Maintenance planning, services and equipment
News Release from: Amtech Power Software | Subject: PowerNet HV software
Edited by the Manufacturingtalk Editorial Team on 12 May 2003

Software predicts plant short-circuit
performance

By facilitating fault-level calculations for the electrical installations at a water treatment works, software achieve savings in excess of GBP 300,000 on the distribution equipment specified.

By facilitating fault-level calculations for the electrical installations at Welsh Water's new Cardiff Waste Water Treatment Works, software from Amtech has made it possible for project manager, Hyder Consulting, to achieve savings in excess of GBP 300,000 on the distribution equipment specified for the plant The savings were achieved by using Amtech's Windows-based PowerNet HV software to predict the short-circuit performance of the plant's complex electrical installation

On the basis of the results obtained, the specifications for the HV/LV transformers feeding the plant were formulated to ensure that fault levels in the LV switchboards would not exceed 50kA.

Although this approach adds a little to the cost of the transformers, it allows the use of readily available standard switchboards, rather than the costly custom-manufactured products which would otherwise have been needed.

Eur.Ing Cedric Garland (C Eng MIEE), Principal Electrical Engineer at Hyder Consulting, commented, "There's no doubt that PowerNet from Amtech played a major role in the HV design work associated with this project.

We met a number of challenging situations during the design phase, but on each occasion, PowerNet helped us to find a definitive solution - quickly and easily.

It has, for us, become a truly indispensable system design tool." Designed to process waste water from the area surrounding Cardiff, the new Cardiff Waste Treatment Works can handle flows of 6.2m3/s under storm conditions, making it one of the largest of its kind in Europe.

The plant's estimated power demand of 14MVA is supplied at 11kV by two parallel-connected 30MVA transformers.

Each separate plant process is then supplied from a local 11kV switchboard, which is fed from the main 11kV switchboard via four ring-main circuits.

LV switchboards supplying pumps and other loads are powered by 18 transformers with secondary voltages of 400V and 690V.

To ensure maximum supply security, the 11kV switchboards are normally interconnected, via switches, in such a way that the transformers are operating in parallel.

This arrangement means that LV fault levels are potentially very high, while the complexity of the system means that manual analysis of short-circuit performance would be time consuming and prone to error.

For these reasons, Hyder Consulting investigated Amtech PowerNet HV s oftware, and found it to be easy to use, dependable, and ideally suited to this application.

The software quickly showed that using standard transformers would give fault levels of up to 80kA in the LV switchboards.

It also showed, however, that by using special transformers with impedances of up to 10% in certain locations, fault levels could be reduced to 50kA.

Further, the Amtech software also demonstrated that, even with the increased impedance of the transformers, the voltage regulation at the loads would still be 5% or better.

On the basis of this data, engineers at Hyder Consulting ordered special resin-cored transformers for the project from Starkstrom Geraetebau, and specified standard 50kA fault-rated LV switchboards.

Savings on switchboard busbars and steelwork alone are estimated at GBP 331,000.

Further savings have undoubtedly been made on circuit breakers, but these have not been quantified.

Amtech is the UK's leading developer of software products designed specifically for the electrical industry.

The company's products are developed in-house, and include programs for electrical design, protection calculations, test and inspection applications, and for interior lighting design.

Committed to innovation, product quality and customer service, Amtech holds BS EN ISO 9001 TickIT accreditation for customer support services and software development activities. Request a free brochure from Amtech Power Software ...

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