There has been a growing focus in recent times on ensuring quality of power supply. The increasing renewable energy integration into the grid and the accelerated uptake of non-linear loads have distorted unidirectional power flow, affecting power quality. Poor quality of power leads to premature failure or reduced/degraded performance of the equipment, increased system losses and unscheduled equipment downtime. Various regulations issued by the Central Electricity Regulatory Commission (CERC) and the Central Electricity Authority (CEA) cover power quality standards and parameters. Besides, power quality standards have also been covered under various state regulations and the grid code. However, these regulations are not uniform across the states and do not provide a comprehensive mechanism for monitoring power quality and incentivising compliance, among other things. In order to tackle this, the Forum of Regulators (FoR), in its 31st meeting, released the Report on Power Quality of Electricity Supply to the Consumers, which has suggested a draft model regulation on power quality, covering power quality parameters and incentivising mechanism, among other things.
One of the key CERC regulations pertaining to power quality is the Indian Electricity Grid Code Regulations. The grid code specifies technical and commercial rules applicable to utilities connected to/or using the interstate transmission system. The regulation facilitates optimal and economic grid operations as well as coordinated and optimal maintenance grid planning. The regulations also specify voltage variation limits across different voltage levels.
With regard to the existing regulations, at the central level, the CEA has also notified a few regulations and standards. The Grid Standards Regulations constitute one of the key CEA regulations on power quality. These standards apply to generating companies/transmission companies/ distribution licenses/bulk consumers, load despatch centres, regional power committees and bulk electricity consumers (connected at the 33 kV level). The regulations specify norms for operations and maintenance of transmission lines, limits for voltage fluctuation and harmonics to be maintained across voltage levels. Further, it lays down steady state voltage limits, temporary overvoltage limit due to sudden load rejection, maximum permissible values of voltage unbalance and parameters pertaining to waveform quality. Apart from this, the CEA has also issued the Technical Standards for Connectivity to the Grid Regulations. These regulations stipulate grid connectivity standards applicable to distribution systems and bulk consumers. The limits specified in the regulations are similar to the power quality standards prescribed by the Institute of Electrical and Electronics Engineers (IEEE) including those under IEEE 519-2014. The regulation specifies standards for voltage and current harmonics, voltage unbalance and voltage fluctuation. In addition to this, the CEA has issued Technical Standards for Connectivity of the Distributed Generation Resources. These are applicable to consumers drawing power at 33 kV or above voltage level across sub-transmission or transmission networks. These regulations stipulate that the applicant seeking connectivity at below 33 kV level will provide a reliable protection system to detect faults and abnormal conditions and provide an appropriate means to isolate the faulty equipment. Further, the regulations state that the injection limits of current harmonics at the point of common coupling by the user should be in accordance with the IEEE 519-2014 standards.
Apart from this, at the state level, various state electricity regulatory commissions have also issued the grid code, supply code and standards of performance that mandate the power quality to be maintained. Broadly, these cover standards of power quality parameters at the distribution level of voltages below the 33 kV level. However, there is a lack of uniformity in power quality standards across states. Meanwhile, various states do not have comprehensive power quality regulations, covering all the necessary power quality parameters, and the monitoring and compensation mechanism.
FoR’s model regulations
With the aim of ensuring uniformity in power quality regulations, the FoR in its Report on Power Quality of Electricity Supply to the Consumers has released a draft model regulation, which could be adopted by state regulators with the desired modifications. The model draft regulations will apply to distribution licensee(s) including deemed distribution licensee(s), distribution franchisees and all designated customer(s) of electricity connected at or below the 33 kV level. Any failure by the distribution licensee or designated customer to achieve and maintain power quality parameters specified in these regulations will render the distribution licensee or designated customer liable to payment of compensation under the Electricity Act, 2003. Further, the model regulations state that the distribution licensee will identify strategic locations in their electrical network and install power quality meters at all such locations to maintain power quality in their supply area. Apart from this, measurement methods for the assessment of power quality under these regulations will be as per the applicable notified Indian Standards (IS) and in the absence of IS, IEC 61000-4-30:2015, namely, “Testing and Measurement Techniques – Power Quality Measurement Methods”, and as amended from time to time.
The way forward
On the power quality monitoring front, although end-to-end power quality monitoring on a continuous basis is necessary, the CERC recommends implementing power quality monitoring in a phased manner. In the first phase, 50 per cent of 33 kV/11 kV feeders and 25 per cent distribution transformers could be monitored; meanwhile, in the subsequent phases, 100 per cent 33 kV/11 kV feeders and 60 per cent distribution transformers; and 100 per cent distribution transformers monitoring could be undertaken. However, some locations need to be monitored regularly from the start itself such as arc furnace, data centres and large industries. Apart from this, since various utilities are already undertaking installation of smart meters, they could consider installing meters that also have features to monitor power quality parameters. With regard to the imposition of incentive/disincentive for meeting/violating power quality norms, the CERC recommends that in the first year customers could just report power quality parameters in prescribed formats, and incentive/disincentive could be imposed from the next year. Later, the incentive/disincentive could be modified, based on the experience and system requirements.
For the successful implementation of power quality standards and regulations, sensitisation of state power regulators and consumer awareness are crucial. Consumers should be encouraged to buy the Bureau of Indian Standards-compliant products. Moreover, training of discom engineers is required for implementing power quality standards. Apart from this, maintaining a power quality database by the distribution licensee or bulk consumers for a sufficiently long period would help in efficient implementation of standards. However, it is essential to ensure data security so that the data is not transferred/shared without permission. Undertaking power audits is also essential for maintaining power quality. The central regulator recommends that 100 per cent audit could be done by self once a year and 5 per cent random audit by an independent agency. The audit results would be presented to the regulator, along with the average revenue realised true-up. Notably, the expenditure undertaken by the licensee towards improving power quality should be a pass-through in the annual revenue requirement; however, disincentive paid by the licensee cannot be a pass-through.
To conclude, ensuring quality of power supply to consumers is essential to enhance industrial production as well as strengthen the Make in India programme. Besides, maintaining power quality is essential for ensuring 24×7 reliable power supply. In order to maintain the desired power quality, it is essential for the state regulators to adopt a dedicated regulation on power quality. Furthermore, with the increasing renewable energy generation and the large-scale adoption of electric vehicles expected in the future, adopting comprehensive power quality standards is essential for maintaining a stable power grid.