The switchgear industry is among the major industries serving the Indian power sector. In coming days the switchgear industry is expected to show healthy growth. The requirement of power in the upcoming industries and the massive rural electrification drive is poised to keep the switchgear industry very busy. In this industry, technology is the basic resource. It is very natural that most of the multinational companies are major players in the switchgear industry has they have access to source technology. However, in the years to come, many Indian companies are expected to upgrade their technologies and develop switchgear products to serve the rapidly-growing power industry.
Before moving to gas-insulated switchgear, it is worthwhile to understand the overall structure and dynamics of the switchgear industry. Switchgear products are broadly distributed across four ranges, and the market trends of each group depend on various criteria like product criticality, technology, safety, price and type of users.
Low voltage
Product criticality: In this range voltage is low and current is high. Hence product is not so critical.
Technology: Mostly air insulated technology is used. This technology is very old and conventional hence many more designs are available. People are also very familiar with the product.
Safety: As the product is not so critical, people give relatively less importance to the safety aspect.
Price: There is huge requirement and hence there is correspondingly large volume of production. This also results in tremendous competition. Most manufacturers belong to the small and medium enterprise (SME) category. Big companies, including multinationals, cater to the low-voltage switchgear segment, largely to keep their presence alive.
Users: Users include utilities, industries and others. The user base is large because these products cater to the last end of the power distribution value chain.
Medium Voltage
Product criticality: As voltage increases, so does the product criticality.
Technology: In this range, air-insulated switchgear was traditionally the only option. However, nowadays gas-insulated switchgear (GIS) has emerged as the latest technology. Most customers prefer GIS for automation and remote operation.
Safety: As the product is critical, more importance is attached to the safety aspect.
Price: All utilities and industries using high-voltage (HV) equipment are the main customers of this product category. Competition in terms of pricing has increased as many local players have developed products.
Users: As discussed, users are utilities and industries that use high-voltage equipment.
High and Extra-high voltage
Product criticality: As the voltage is high and extra-high, product criticality is greatly enhanced.
Technology: In this range, air insulated and gas insulated switchgear are the only options. In open air substation, air insulated switchgear is preferred and for indoor substations, users go in for GIS. In this range, technology is very important and most of the manufacturers are major companies. There are no small and medium scale manufacturers in this range.
Safety: Switchgear products in this range command high importance to safety.
Price: All utilities and industries are the main customers. Price pressure has somewhat increased as many local players have developed products.
Users: Users are utilities and industries that use HV equipment.
Gas Insulated Switchgear
Gas insulated switchgear (GIS) is very compact form of switchgear. Because of the use of SF6 (sodium hexafluoride) insulation, the size of the switchgear reduces drastically. This product is normally used in medium and high voltage application.
GIS is more safe, compact and maintenance-free as compared to AIS. The longevity of GIS is also higher than AIS. In GIS most of the current-carrying and live components are sealed in SF6. Constant atmospheric conditions in the sealed tank improve the performance of switchgear.
In GIS, design is the most critical aspect. Most multinational companies have developed this product in their global technology centres. In India very few companies have developed GIS designs. Designing of GIS or technology of GIS is not available easily. While designing few important points, designer should look at critical aspects like leak-proof joints, over-pressure sustaining capacity, maintenance-free mechanisms and overall performance of all components to sustain guarantee of 15-20 years in field.
The challenges in GIS manufacturing can be overcome by taking utmost care at three stages:
Design: Selection of proper raw material is very important. Sealing material is very important because in India temperature variation band is very wide. Tank design to sustain the internal arc is very important and critical. The selection of the material should be based with a clear understanding of the required mechanical strength.
Manufacturing: perfection in assembly and on component level is required. Multistage inspection is required.
Erection and commissioning: All procedures given by the manufacturers need to be followed meticulously.
Space is the biggest constrain in India. Other functional criteria like safety, maintenance and downtime are the key parameters for distribution. All utilities and industries are looking for safe and maintenance-free products. It has been proved that after installing the GIS cost of maintenance and cost of production loss due no power has dropped drastically. Whereever uninterrupted power supply is required, GIS can be used.
Type testing of the GIS is very expensive task. Testing facilities for some of the tests are not available in India. For switchgear manufacturers, it is very difficult to undertake some part of the testing in India and some outside India. Hence most of the manufacturers prefer testing the entire equipment at international laboratories. Product certification from international laboratory helps to capture the market outside India as well.
Process control is the main function in the manufacturing of GIS. Small mistake in the component or assembly affects the performance of the entire GIS. At every level of the manufacturing process, inspection is required. Testing for gas leakage requires huge investment.
In summary, some of the major shortcomings in GIS development in India are lack of designing ability and manufacturing skills; and inadequacies of type-testing laboratories and local testing facilities.
China is a very attractive market for GIS and its components. In many utilities, China-make products are not approved. However, many manufacturers are using auxiliary components for GIS from China.
The author of this article, Milind M. Kulkarni, is a switchgear design consultant, and the Founder of Vadodara-based Ultimate Switchgear Solutions Pvt Ltd. He may be contacted via email on milind.kulkarni@ultimateswitchgear.com or milindmkulkarni68@gmail.com, or by phone on +91 97277 57921.
(Featured photograph for illustration only)
