The Electricity Act, 2003 highlights the basic need of consumers for continuous, reliable and quality supply by the distribution utilities. With the accelerated growth of renewable energy such as solar and wind; and the rise of non-linear loads from automation, electric vehicles (EVs) and charging stations, LEDs, and metro and railway electrification, the quality of conventional unidirectional power flow from generation to consumption points has become a challenge. The poor quality of power can lead to premature failure or reduced/degraded performance of equipment, and increased system losses.
The 31st Forum of Regulators (FoR) meeting highlighted the need for greater regulatory intervention in ensuring the quality of power supply, and the need for effective compliance with the power quality standards.
Need for power quality regulations
Since power quality is a distribution area, it is a state subject. Hence, the state electricity regulatory commissions (SERCs) frame power regulations. Notably, various power quality parameters such as total harmonic distortion and voltage level are covered under different state regulations, the Central Electricity Authority standards, the Central Electricity Regulatory Commission (CERC) grid code, and the SERCs’ supply code. However, an exhaustive list is lacking. This necessitates the need for a separate regulation that exhaustively covers all the parameters, along with an incentive and disincentive mechanism for each parameter. There is a need to emphasise the importance of power quality and have a harmonious framework across the country, laying down the procedure for monitoring, management and control of all aspects of power quality. Further, reliability indices like system average interruption frequency index (SAIFI)/system average interruption duration index (SAIDI), which are a part of the state regulations, could be a part of the power quality regulations.
It has been noted that certain issues at the transmission and sub-transmission system level can also hamper power quality. This necessitates the need to monitor power quality parameters in the entire value chain to identify and install the mitigation mechanism. An appropriate reporting and incentive and disincentive mechanism can be implemented by the regulators in the grid/supply code for regular monitoring and control of the limits for power quality parameters at the transmission and sub-transmission system level.
Recommendations for the formulation of power quality regulations
A subgroup on power quality under the FoR has suggested to specify the power quality parameters including harmonic distortion, voltage variation and flicker, voltage unbalance, voltage sags/swells, and short and long supply interruptions in the power quality regulations. The limits for these power quality parameters could be included in the power quality regulations by the SERCs based on their experience and specific system requirements. It needs to be ensured that the specified limits for various power quality parameters are consistent with the notified BIS standards or applicable IEEE/IEC standards. Moreover, the limits recommended for various power quality parameters in the model regulations on power quality may be followed, till the BIS/CEA notifies its distribution system supply voltage quality standards, after which the notified standard limit may be implemented by the SERCs.
Further, there should be continuous power quality monitoring and reporting at all the identified locations. The monitoring can be done in a phased manner by the SERCs depending on the local conditions. Data centres, large industries, malls, distributed generation sources, EV charging stations, inputs of transformers for solar/wind generators and equipment such as arc furnace could be monitored in the first phase. In the initial phase, the regulators may direct the distribution licensee to install power quality meters at all strategic locations and for bulk consumers with contract demand exceeding 1 MVA.
From the first year onwards, compliance may be reported in standard formats at regular intervals. In the second year, the incentive or disincentive (in the case of defaulters) can be drafted as per the recommended regulations. In the third year, the incentive/disincentive can be decided based on the experience and specific system requirements. The distribution licensee could make efforts to improve power quality in its supply area by deploying devices such as filters or controllers to mitigate power quality issues. The expenses incurred towards deploying these devices by the distribution licensee can be passed through in the ARR by the regulators. However, the disincentive paid by the licensee cannot be passed through to consumers.
Further, the SERCs may assign the responsibility of maintaining a power quality database to the distribution licensee or bulk consumers, for a sufficiently long period to enable analysis. For this, data security should be ensured and the database should not be transferred/shared without permission. A compliance audit of power quality parameters can also be undertaken through an independent agency, and the results may be filed along with the ARR petition. Meanwhile, some power quality parameters can be published for raising public awareness and increasing stakeholders’ engagement through the feedback system. The timeline for redressal of consumer complaints with regard to power quality should be 2/10/180 days, depending on the nature of the issue.
For the effective implementation of the power quality standards, discom engineers need to be sufficiently trained. Further, consumer awareness is important to understand the ill effects of poor power quality, and the need to install BIS-compliant products.
Notably, the FoR issued model regulations in August 2018, which can apply to distribution licensees including deemed distribution licensees, distribution franchisees and all designated customers of electricity connected at or below the 33 kV voltage level. Any failure by the distribution licensee or designated customer to achieve and maintain the power quality parameters specified in these regulations will render the distribution licensee or designated customer liable to the payment of compensation under the EA, 2003 to the affected entity. The distribution licensees will identify the strategic locations in their electrical network and install the power quality meters at all such locations to maintain power quality in their supply area. The measurement methods for the assessment of power quality under these regulations will be as per the applicable IS standards, and in the absence of IS, the IEC 61000-4-30:2015 namely, testing and measurement techniques – power quality measurement methods.
The introduction of the model regulations has increased the adoption of power quality parameters by the SERCs of Maharashtra, Tamil Nadu, Punjab, Haryana and Kerala. Further, the IS 17036 standard on distribution system supply voltage quality has been adopted by BIS, while the power quality monitoring standard is in advanced stages of adoption.
The way ahead
Broadly, there is a need to continuously monitor the extended range of power quality parameters, measure saving opportunities beyond power factor and harmonics, improve energy efficiency with power quality improvement initiatives, and comply with the present and upcoming power quality regulations. Licensees could look at adopting system solutions rather than product solutions.
Going forward, power quality can be integrated with smart grid applications in distribution. Advanced power quality meters can be deployed to undertake wide-area power quality measurement. Further, power quality enhancement devices are necessary for system component and sensitive loads that can provide fast diagnosis and correction of power quality disturbances. Power quality measurement for smart grids may be further extended for grid intelligence as part of the power quality regulations. n
Based on a presentation by Shilpa Agarwal, Joint Chief, Engineering, CERC, at a Power Line conference
