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 Case StudiesVirtual ControlSite Adoption
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Case Studies | ||||||||||||||
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Typical Case studies The following is a simple list of small problems that we have recently dealt with on a some sites and although not major problems the provision of suitable engineers who are able to identify risks and work with many organisations can provide cost effective project management that can quickly pay for itself by reducing wasted expenditure. Co-ordinated Activities between all Agencies The FM company arranged construction work that necessitated the re routing of the HV cables and the addition of a new transformer. The company providing on site AP services were not made aware of the changes until the day before work was due to start and had to rapidly make arrangements for shutdowns and a total review of the protection grading on the site. By having a project manager dedicated to the site this problem would not have occurred as the long term development of the site would be discussed at regular intervals in meetings held with all active parties on the site. Poor network Design Maintenance on a transformer was not carried out in a safe method as the network had been changed to prevent the sae isolation of the transformer on its own. Although there transformer was dead and had been safely proven dead many of the safety rules could not be complied with and there was no safety earthing provided for the work as the network could not be shut down to an extent where the earth could be safely applied. By having a dedicated site manager this situation would not have arisen as he would have investigated all shut down situations and made recommendations on where the potential weaknesses in operating capability existed. Lack of record keeping and Management When work had to be carried out on site the AP brought in to do the work noticed that the diagram was out of step with the labelling on the switchgear. It subsequently became clear that many changes had been made to the network which the FM company running the site had not considered the need to update the network diagram. Although their own mimic diagram had been updated paper copies of the diagram, Substation names and switchgear labels had not been changed. By having a dedicated site Manager frequent checks would be made to ensure that the operation fo the network was safe. He would have checked that site labels switchgear labels etc all matched up with the current paper and mimic diagrams and would ensure that all staff had access to controlled copies of the network diagram. One of our key processes is to build a network diagram and publish this on our Intranet site so that we are certain that at any time all staff operating at the site can get the latest version of the diagram. A company were called in to carry out changes to the protection settings on a circuit breaker controlling a 1600kVA transformer. This was as a result of a protection review following the buildings construction prior to completion and handover of the building to the site FM company. When the site was visited by an engineer to carry out the changes it was found that the type of relay on site either needed to be on load or have a separate battery pack to allow changes to be made. This had not been specified and the job which included major commissioning tests on the sites generators could not be carried out until a battery pack could be provided over 1 week later. It subsequently became clear that there had been little co ordination between the parties on site and that an inappropriate type of circuit breaker and relay had been used and on further review it was clear that there was no need for the circuit breakers to be on site at all as they were in series with the electricity board main supply breakers which in effect protected 50m of HV cable between the incoming substation and the transformers. Simple transformer feeders would have been cheaper to build, cheaper to operate and maintain and offer more reliability than the installed design. By getting us to oversee the design and work closely with all of the parties involved with the building at an early stage the duplication in protection would have been identified and raised as an issue at a time when it could have been resolved. IF the network had been passed to us for management when reviewing the network our engineer would have identified the need for the battery pack to be made available on site. A company operating in a dusty environment used 11kV oil filled Circuit breakers to control the operation of a number of motors used for milling and crushing. Due to the operating nature of the site and the frequent operation fo the circuit breakers maintenance was being carried out at 3 monthly intervals with subsequent lost production costs and high maintenance costs as well as the risk that the circuit breakers would not operate properly if called upon to do so in an emergency. Our dedicated engineer would have offered the site owners the option of changing the circuit breakers to a type that could more easily cope with the environment and the frequent switching and therefore need less maintenance and therefore offer a very fast payback of investment While carrying out transformer maintenance safety rules could not be complied with due to the operator of the site building a temporary security wall to segregate the HV switches from the LV switchgear panels in an effort to restrict entry to the HV plant area to HV AP staff only. Unfortunately he had not understood the principles of withdrawable switchgear and it was not possible to rack the circuit breaker out the housing due to the close proximity to the security wall. Our site engineer would have immediately identified the need for a segregated area and would have worked with the site owners to ensure that all means of access to the switchgear was sufficient to allow normal safe operation. |
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