Do away with outdated tests and adopt environment-friendly practices, say Sandeep Ghosh and Narayan Bhat.The electrical equipment industry has a very promising future with the expected industry growth and planned power capacity addition in the 11th and 12th Plan period. The switchgear industry reported average combined annual growth rates of around 14-15 per cent whereas the cables segment registered the highest growth of around 16 per cent. Accelerated power growth plans of the government and reforms in transmission and distribution has opened a big venue for these industries but the market is even wider as most plants in oil and gas and other industries have reached the stage of replacement of their age-old systemsMost Indian manufacturers are struggling to achieve margins in view of low-cost products from China while the price of steel, copper, aluminium, etc., is rising. Stiff challenges are faced with the entry of low-cost suppliers and also with high-quality sophisticated technology suppliers. The renovation and modernisation of the industry has given a large opportunity for low voltage (LV) and medium voltage (MV) market, but extreme competition is seen in this segment with the entry of new players and the tolerance of the buyer to low quality and low-cost products. While growth of HV and extra high voltage segment is directly driven by capacity addition and transmission and distribution (T&D) plans, the sophisticated product entry from international suppliers affects electrical manufacturers of India. Though Indian manufacturers have mastered the technology of circuit breakers like bulk oil, minimum oil, air blast and vacuum to SF6 ranging from 240 V to 800 kV, still gas-insulated switchgear technology has not matured in India.Safety of switchgearSwitchgear technology was built over the years for safety, reliability and efficient operation of electrical systems. In general, switchgears have a proven record of reliability and performance. Failures are rare, but when they occur, the results can be catastrophic. Oil-filled switchgear failures like tank ruptures can result in burning of oil and gas clouds can cause death, injury and damage the immediate vicinity. Modern technology with sulphur hexafluoride (SF6) and/or vacuum has removed the hazard of burning oil but introduced other risks that need to be managed. The ability to perform safely depends on its condition of operations. The use of vacuum and SF-6 circuit breakers has made the size of switchgears more compact when compared to oil or air-circuit breakers.The main application of switchgears is in the protection of circuits against damage caused by faults and the restoration or preservation of supplies to as large a part of the system as possible following a fault. The fundamental principle on which switchgears are designed is to quench the arc, separate contacts to overcome high potential due to transient at the required speed. The governing factor has been the rate of rise of recovery voltage (RRRV). This is achieved in circuit breakers using oil, gas, vacuum or air and constructed with required dampening. Emerging technologies have added new concepts like soft starters, intelligent relays, intelligent bus bar etc., to cut short the time to respond during the transient or faults. Hydraulic-based circuit-breakers have advantages in terms of response time as compared to mechanical, spring-charged power units. The technology of SF6 with puffer or piston system aimed at the arc helps to create a jet that aids arc extinguishing and also helps in keeping the contact movement to the minimum through sliding sleeves. Graphite contact tips are more effective technologies in the breaker today. They provide long lasting contact tips as compared to copper or copper-silver alloys.Obvious delays in response associated with oil-filled switchgear and its bulkiness, are mostly a reason for their fading in the market. However, the technology being proven, they are still deployed in remote, unmanned substations in India. Vacuum technology has its own limitation in terms of voltage rating - rarely are ratings above 11 kV seen in the market. Technology with sulphur hexafluoride (SF6) has shown promising features with an advantage in terms of speed and high voltage ratings in the range of 15 to 400 kV and flexibility to enhance ratings to 800 kV or more with synchronised series combination.GIS-based switchgear units have their own merits with their compactness - better insulation technology and retardance at fire-hazard zones. However, the upkeep and maintenance of such gas-based sub-stations remains high. GIS technology leads to compact substations. With abundant land availability in India the need to shrink a substation size is not yet a priority. Thus, such GIS may have restricted applications in India like for instance in nuclear power stations where the perimeters are strictly defined and controlled. The world is moving towards reliable and safe technology and India needs to gear up its usage.Challenges in the cable industryIn the cable industry, power cables are especially growing very rapidly. The challenge of the cable industry lies in satisfying the market need at an economic cost amid new technologies and players. Extruded cable manufacturing is fast-growing for high voltage and extra high voltage. The highest standards need to be implemented in materials, manufacturing and installation and in O&M to assure reliability as well as cost-efficiency.Are we following old standards?Cables are subjected to various tests like type, acceptance and routine tests from the design phase of a cable to the installation phase for checking their proper functioning. Also tests are conducted after installation. During the O&M phase, diagnostic tests are carried out to find out their condition. The types of tests vary with construction features like shielded or screened or non-shielded or unscreened depending on their voltage rating. Mostly cables are made to comply with IS standards except for special tests conducted in line with IEC or IEEE. Many a times it has been observed that clients and consultants still specify the age-old tests which are irrelevant with modern and improved technology of manufacturing cables. Avoidance of some of these tests may prevent the release of harmful gases in to the atmosphere. For instance, the fire retardant low smoke (FRLS) tests involve actual burning of the sheath and insulation to determine acceptance. With very refined polymers now available, such tests not only meet the specified requirements, but exceed them by a 50 per cent margin in most cases. Thus, the effort to rig up the test, conduct and measure are meaningless. Not to add that the toxic fumes released by burning these cable components are not environment-friendly. These tests could easily be avoided by much safer tests on the polymer to determine FRLS properties.Another area that will affect the cable industry in India soon will be the supply of cable drums. In the case of low voltage cables up to 120 sq mm, these cable drums are made of wood and are hardly re-usable. Compare this with steel drums (mostly used in XLPE cables) which are collapsible and re-usable. Given the restrictions on forest land coming in, there is already a supply constraint on wood for cable drums. The wood used for cable drums in India are extremely low quality and thus cannot be re-used at the end of a single delivery and is mostly scrap. The West has for long switched over to polymer drums for smaller size cables, which are re-usable. Cable companies provide a cash incentive to the buyer to return the drums for re-use. This operation is certainly more environment-friendly and can go a long way towards protecting our depleting forest resources. Indian manufacturers could adopt this in future.The growth and fortunes of the electrical industry are largely dependent on the overall industry growth. Highly competitive market scenario prevails in this sector which needs manufacturers to think differently and balance innovativeness in technology and need. Most low-cost vendors are successful with customer intimacy and for long term sustenance, highly reliable and efficient products with right-fit solutions are a must. The industry also needs to start investing and exploring environment-friendly processes as part of their support to the cause. These will soon be the law and the time to start is "now".The authors are Technical Training & Business Assurance Manager - Energy and Head Power Asia, Lloyd's Register. Views are personal.
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