The proper functioning of various power equipment across the generation, transmission and distribution segments is crucial for reliable electricity supply. It is, therefore, essential for utilities to carry out regular testing and measurement (T&M) activities to ensure seamless performance of equipment through the power value chain. The need for T&M is expected to increase manyfold in times to come, owing to the increasing complexity of the power system with greater integration of renewables and distributed energy resources (DER). The intermittency associated with renewables affects grid operations significantly, so it is imperative that all equipment in electrical networks works efficiently to ensure grid stability. In addition, with the growing pace of energy transition, T&M solutions for wind turbines, solar modules and emission control equipment are expected to gather pace.
Test types and existing facilities
Various types of tests are conducted on electrical and mechanical equipment used in the power sector. These include type tests, routine tests, special tests, factory acceptance tests (FATs) and site acceptance tests (SATs). Type tests are typically conducted on power equipment before they go for commercial production after finalisation of the design. These tests are done mainly on prototype units and not on all manufactured units in a lot. Routine tests are conducted mainly for confirming the operational performance of an individual unit in a production lot as per relevant standards. Special tests are undertaken as per customers’ specific requirements during operations and maintenance of the equipment. FATs are usually conducted at the factory works to ensure that user requirements are met and SATs are taken at specific places where commissioning is usually carried out.
There are several original equipment manufacturers (OEMs), vendors and third-party testing agencies in the Indian market. Many equipment manufacturers and utilities have set up advanced testing facilities for ultra-high voltage/extra high voltage systems, transmission towers, cables, meters and advanced switchgear. National Accreditation Board for Testing and Calibration (NABL)-accredited labs such as the Central Power Research Institute (CPRI) and the Electrical Research and Development Association regularly conduct testing and certification of transmission and distribution (T&D) equipment. For testing high voltage equipment, NTPC Limited, NHPC Limited, Power Grid Corporation of India Limited, the Damodar Valley Corporation and CPRI have together set up the National High Power Test Laboratory at Bina, Madhya Pradesh. In addition, there is an independent hydraulic turbine model testing laboratory at the Indian Institute of Technology, Roorkee, to carry out scale model tests of hydraulic machinery based on IEC 60193 international standards. For renewables, the International Advanced Research Centre for Powder Metallurgy and New Materials has set up a concentrated solar thermal-based test rig facility at Hyderabad.
Key trends and developments
The country has set a target of 500 GW of non-fossil fuel capacity by 2030. This would require stepping up of testing facilities for renewable energy equipment. Taking cognisance of the growing need for manufacturing and testing facilities for renewable energy and power equipment, the Ministry of Power (MoP), along with the Ministry of Renewable Energy (MNRE), invited expressions of interest in May 2022, for setting up a manufacturing zone for power and renewable energy equipment, integrated with a common infrastructure facility (CIF) and a common testing facility (CTF), on a pilot basis.
The scheme envisages setting up of two brownfield and one greenfield manufacturing zones with a proposed funding of Rs 10 billion, with a ceiling of Rs 40 billion. Entities selected under the scheme are required to start execution of works relating to CIF or CTF, in collaboration with the CPRI, the National Institute of Solar Energy (NISE) and the National Institute of Wind Energy (NIWE). Works related to CIF are to be completed within 18 months and those related to CTF within 36 months of the date of approval of the detailed project report. The selected company (special purpose vehicle or SPV) needs to ensure that from the grant-in-aid provided by the central government, CTFs are established with the help of NISE for solar energy, NIWE for wind energy and CPRI for power equipment (for generation, distribution and transmission) as per the testing requirements of manufacturing units set up in the manufacturing zone. NISE, NIWE and CPRI will establish and operate testing facilities and charge testing fees as per the agreement with the SPV.
Smart meter testing is another emerging area, given the government’s focus on replacing nearly 250 million meters with smart ones, under the National Smart Metering Programme. Other programmes such as the Revamped Distribution Sector Scheme and the National Smart Grid Mission also lay emphasis on smart metering. As a result, utilities and manufacturers need to ramp up facilities for T&M of smart meters. In October 2021, Tata Power was accredited by NABL for its test lab in Mumbai for secure and standard testing of smart meters. The lab is equipped to monitor meter data communication on a real-time basis and has automated facilities to conduct remote connect/disconnect, remote firmware upgradation, tamper event logging and inter-laboratory comparison testing for smart meters.
T&M of other equipment such as transmission towers, cables, conductors, transformers and reactors continues to hold significance for their fail-safe operations. In addition to routine and type tests, diagnostic tests are being conducted by utilities to assess the health of the operating equipment. Nowadays, utilities are adopting aerial patrolling techniques such as helicopters and drones equipped with light detection and ranging (LiDAR) sensors, thermovision cameras, corona cameras and high resolution video and digital cameras for identifying transmission line defects. The health of underground cables can be assessed with very low frequency testing. Along with conventional equipment testing practices, tests such as sweep frequency response analysis and excitation for HV transformers, capacitance and tan delta measurement for other critical equipment, dynamic contact resistance measurement of breakers are crucial.
In the generation segment, T&M solutions such as continuous emission monitoring systems and predictive emission monitoring systems are gaining traction for monitoring power plant emission levels and undertaking corrective actions.
Recent CEA guidelines
In March 2022, the Central Electricity Authority (CEA) issued the Guidelines for the Type Tests for Major Equipment in Power Sector. The CEA noted that the frequency of repetition of type tests by Indian utilities, even if the equipment has remained essentially the same (in terms of basic design, construction, material and manufacturing process) varies from utility to utility. Certain utilities do not accept type tests already conducted on equipment of the rating/specifications and demand repetition. Often testing time exceeds the entire production time (for instance, over-voltage cycling test for capacitors) and facilities for type tests for some equipment are not available in India, because of which the equipment is sent abroad for testing. Time and again, manufacturers and utilities have called for uniform guidelines related to type testing, following which the CEA has notified these guidelines. The guidelines aim to reduce the repetition of tests, wherever possible, to avoid overloading of testing facilities and to avoid discrepancy in the validity period of type tests being accepted and followed by various manufacturers or utilities.
The CEA also notified the Guidelines for Model Quality Assurance Plan (MQAP) for major power sector equipment in May 2022, after taking cognisance of variance in the quality assurance plans being followed by different manufacturers and utilities. The MQAP seeks to define the number and type of tests being performed on equipment during the entire cycle from raw material sourcing to production, to commissioning, in order to reduce unnecessary testing, avoid redundancy at various stages and in turn, save time and cost. Testing is also necessary to ensure safety at power plants. In May 2022, the CEA issued a safety advisory to all thermal power generating units, following an order by the National Green Tribunal, to undertake safety audits in power plants. Besides general safety and fire safety guidelines, the advisory seeks gencos to compulsorily undertake turbine over-speeding test as per the recommendations of OEMs as well as undertake load testing of all operations and maintenance tools/equipment.
Conclusion
The need for T&M solutions is set to increase in the coming years as the power sector expands and becomes more complex. T&M is crucial to ensure that power equipment is fit to ensure safe operations and reliability of the grid.