Sparks Electrical News May 2020

CONTRACTORS’ CORNER

6

WORKING KNOWLEDGE WITH TERRY MACKENZIE HOY

Misconnections and the possible repercussions

W hile many businesses, homeowners and public establishments look to reduce elec- tricity usage and increase their security of power supply, it is critical that they consider their needs before deciding on new elements of power supply. This is according to Nick Oosthuizen, Manag- ing Director at Inframid and consultant in energy effi- ciency, who highlights the importance of understand- ing your electrical load before investing in new power supply systems. “Schools are a clear example of why you can- not take a one-size-fits-all approach in efforts to secure your power and save energy. School loads are not only seasonal but also vary throughout the weeks and days,” says Oosthuizen. He rec- ommends that you undertake an in-depth finan- cial feasibility study that weighs up all elements of power supply in relation to the prevention of downtime and assuring return on investment. “The first step is to conduct an ‘electrical audit’ and understand your current electrical load, which will help to identify the real needs for special sup- ply systems and avoid fruitless expenditure. It is thus important to know your electrical demand, load content, and electrical distribution architec- ture.” To assist in understanding your electrical load needs, Oosthuizen explains that there are at least five different segments to consider: essential loads, critical no-break loads, non-essential loads, energy inefficient loads, and your total load pro- file over time. It is fundamental to determine the different load categories you are dealing with, first so that the different types of power supply systems can be applied appropriately, secondly to avoid over-sized and therefore over-priced sys- tems, and thirdly so that the potential for load re- duction and renewable energy can be considered all with the view to achieving acceptable return on investment (ROI). Essential loads The essential load is made up of electrical systems that are fundamental to help the school remain op- erational, and to keep safety and security systems going. These essential loads require reliable backup power supply sources in order to maintain the elec- tricity supply under mains fail conditions for as long as needed. For schools, these normally include class- room lighting, educational sports facilities, power points for educational systems, offices, learning and admin computer systems, printers, projectors, essen- tial water pumps, etcetera. Critical no-break loads No-break loads are those elements of the essential load that need seamless power transfer and can- not tolerate even a split-second unplanned break in power supply when switching from utility supply to Being really old school I checked if all the circuits were dead with a tester. They were not. Two were still alive, prob- ably due to a back feed, I thought. So, I sorted that out and started looking. I found the cause of the fire: somebody had recently installed a power factor control system. They had installed, in a separate panel, a brand new power fac- tor control system with contactors and capacitors and a controller. There was no current sensing connection. They had just connected a four core cable directly onto the main board busbars and run it to the power factor panel. The power factor panel switches were such that all the capacitors had been switched in manually. The four core cable was too small so it overloaded and caught alight. This set some of the busbar droppers alight and soon the S ome years ago I was appointed to investigate the cause of a fire at a shopping mall in the Western Cape. It was nothing complicated – a fairly large switchboard had caught fire and burnt out. The board was a free-standing compartmentalised switchboard with a 630 amp incoming circuit breaker and various circuits fed off the busbars via circuit breakers. So I set to work.

whole board was burning. This set alight some empty boxes stored in the switch room and soon the whole place was on fire. The firemen were well trained and had the main supply isolated before putting the fire out – after which the shopping centre was fairly well damaged. It all got sorted out in the end and I got a fairly good fee for my report. I was stunned that anybody would connect anything directly to busbars. I was astonished to find that the person who had done the in- stallation was doing five other installations for the same retail group. I told the insurance people that this was a bad idea but they brushed it all off. This was about 20 years ago. Then I read about Swis- sair flight 111. On 2nd September 1998, the plane took off fromJohn F. Kennedy International Airport. On board were 14 crew members and 215 passengers. Shortly, a strange smell was detected in the cockpit, and four minutes later smoke appeared. At the time, the pilots believed there was an issue with the air conditioning system and were unaware of the rapidly intensifying fire in the ceiling. Af- ter consulting air traffic controllers, it was decided that the airplane would land in Halifax, some 56 miles (104 km)

is installed which, although it uses electricity, is not quite electrical, for some reason people think that there is no real skill needed in the installation. Even worse, when some smooth talker tells you, “We’ve done many of these, never been a problem,” it is no comfort to know that there is thus more than one de- fective installation out there. I wonder if the Swissair management were told: “Install this entertainment system in the proper way or 229 people will die,” would they have taken more care? We all should.

away. At about 10:21 pm (ADT), the pilots altered course in order to dump fuel. Three minutes later, they declared an emergency as various systems on the plane began to fail and the cockpit began to fill with smoke. Shortly thereafter air traffic controllers lost contact. The aircraft hit the water at about 10:31 pm, reportedly almost upside down, and broke apart on impact. All 229 passengers and crew died. An investigation was conducted by the Transpor- tation Safety Board (TSB) of Canada. In 2003 it an- nounced that the crash had resulted from faulty wir- ing that ignited the flammable insulation above the cockpit. The TSB had earlier recommended stricter standards concerning flammable materials and electrical wiring. Although the final report did not cite what part of the electrical wiring was at fault, a newly installed entertainment system was believed to have played a role in the fire. The phrase ‘newly installed entertainment sys- tem’ made me think of my burnt down shopping centre. The authorities are swift to make sure that regulations are complied with, but when something

Know your electrical load before investing in new supply systems

Bird deterrent laser prevents second biggest cause of substation power outages I nnovative bird deterrent lasers provide success- ful results at substations that are plagued by bird-caused power outages. This high-tech solu- tion to a longstanding problem will help substation operators prevent outages, improve reliability, and reduce repair and equipment costs. Birds are the second biggest cause of power outages in the U.S. according to a December 2015 report by T&D World, an online publication that covers matters relating to the electric power-de- livery system. An IEEE survey reported that 86% of the utility companies that responded indicated birds caused major problems in substations, sec- ond only to squirrels. Electrical substations are plagued by bird roosting and bird droppings. One bird left 24 000 people without power in San Diego, California, in November last year by coming into contact with a substation, affecting schools and residents in the area. Many were without pow- er for hours. The currently available bird deterrents – coverups, noisemakers, fake predators, fog ma- chines – only provide temporary, spotty relief. La- sers offer a superior alternative and a long-term solution. The AVIX Autonomic laser bird deterrent technology takes advantage of bird’s natural in- stincts. Birds perceive an approaching laser beam as a predator and flee to seek safety when the laser beam passes by. There are a couple of thou- sand users of the bird deterrent lasers worldwide. TransGard, a leading expert in animal-deterrence at substations, confirmed the need for this tech- nology. “15 utility companies in 10 U.S. states are already using the AVIX Autonomic lasers,” says Bill Reichard, TransGard President. “Power outages have a serious impact on our daily life. Autonomic lasers offer a unique – and uniquely effective – solution. They will be able to protect hundreds of substations at risk for bird-caused outages.” The AVIX Autonomic lasers are designed and manufactured by Bird Control Group. Their laser products have demonstrated their effectiveness in a wide range of sectors, including agriculture, aq- uaculture, commercial buildings and airports. Steinar Henskes, CEO of Bird Control Group, is excited about helping utility companies to solve their bird problems. “I am proud that we can now provide the utility market with a successful bird deterrence solution, next to the other sectors we are also serving.”

pumps are other considerations. In general, pumps have a very low power factor, which means they draw higher current than necessary. “Where schools have many pumping systems, it is worth considering power factor correction to these loads to increase the power factor, which will decrease the reactive power with various cost benefits, such as lower demand charges, avoiding reactive power penalties and freeing up dis- tribution system capacity” advises Oosthuizen. Load Profile “When determining your school’s power supply needs, some forethought can go a long way to ensuring ap- propriate systems,” says Oosthuizen. “You should de- termine your total load profile for at least a year, bear- ing inmind that school loads are seasonal and change from day to day. When determining your load, don’t only use utility account information – this normally only provides monthly maximum demand where ap- plicable and energy usage. In addition, it is important to understand which parts of your load can be moved to non-operational times, such as after 15h00, when total consumption is less. There are many timer and automation technologies on the market that can help with load shifting in order to spread the usage curve,” says Oosthuizen. “Investing in an alternative power supply sys- tem for your school is a good idea, but for it to be a feasible investment you must clearly understand your load requirements before making any deci- sions. Knowing what you have is the critical first step to knowing what you need next. Analysing this resultant need for alternative power supply solutions against your potential loss of business, loss of information, and energy savings forms the essence of your business case for investment,” concludes Oosthuizen.

backup power. In a school, seamless transfer is need- ed in areas such as administration and classroom computing systems where valuable information will be lost if power supply is interrupted. “These no-break loads require uninterrupted power supply (UPS) sys- tems when the main power supply fails,” says Oost- huizen. As these UPS systems are normally battery and sometimes solar supported and very costly, it is important to know exactly what size the no-break loads are and how long they will need to be supplied by the UPS systems. Non-essential loads “Non-essential loads include those systems for which you don’t need backup in any form. It is the part of your load that the school can do without while remaining operational during mains fail conditions. An example of this might be geysers, heaters, air-conditioners, pool heating, and pool pumps, which are not essential for running a school.” However, if you lose your utility supply for long periods, the situation might change, as will the definitions of the non-essential loads. Inefficient energy loads According to Oosthuizen, inefficient energy loads include electrical elements that can be replaced by energy-efficient alternatives to make the load less bearing. “These lend themselves to energy saving in day-to-day operations. For example, all new geysers must comply with the new minimum standard as set by the Department of Energy, namely Class B, as specified in SANS 151, to ensure less pressure on your electrical load,” he explains. In schools, the replace- ment of air conditioners and electric heaters with the latest state-of-the-art low energy and unity power factor technology will have quite an impact on en- ergy consumption. Changing older light fittings to the newest technology LED fittings will also have a sig- nificant impact on energy usage. Water and sewage

Enquiries: www.birdcontrolgroup.com

Enquiries: www.inframid.co.za

SPARKS ELECTRICAL NEWS

MAY 2020