The prime objective of the electric power industry in this era is to meet growing demand cleanly, reliably, sustainably, and at low cost. The Smart Grid vision is aiming for new products, processes & services, improving industrial efficiency and use of cleaner energy resources. As per National Smart Grid Mission (NSGM), the total estimated cost for all the projects and NSGM activities for 12th Plan is Rs.980 Crore including a budgetary support of Rs.338 Crores. Initiatives like microgrids, EVs, solar rooftop system are directed towards improving Quality and reliability of Power and will be partly-funded under NSGM.

With this investment, the vision promises to transform the existing grid into an intelligent & efficient grid with the help of smart technologies. But with the increasing smartness of the grid, are we really thinking about power quality? If not, then we need to! Because quality focussed grid, capable of delivering power quality; free of sags, spikes, disturbances, and interruption will be one of the crucial characteristics of smart grid.

Power quality is one of the key aspect of smart grid’s functionality. Implementation of smart grid requires the balance between two main aspects: efficiency and reliability. Often reliability is given priority however, it is not always guaranteed.

"Power Quality is an important aspect for successful and efficient operation of existing as well as future grid"

Power quality guarantees the necessary compatibility between the sensitive electrical and electronics components to assure an uninterrupted and high-quality supply of electricity in future. PQ is therefore, an important aspect of the successful and efficient operation of existing as well as future grids.

This blog draws attention to the kind-of subsided but an important aspect of smart grid- ‘Power Quality’.

POWER QUALITY ISSUES RELATED TO SMART GRID

The concept of smart grid lies in the integration of information and communication technologies into the existing power system infrastructure to give maximum benefit to the end-user. This blend of technologies and sources of energy can be expected to have an impact on power quality, likely negative, with PQ problems becoming more rather than less troublesome. Some of the prominent PQ issues in the smart grid are mentioned below:

• Emission by new devices
  With implementation of smart grid, we envisage growth both in distributed generation (production at lower voltage levels) and in new types of consumption (for example, charging stations for electric vehicles, expanded high-speed railways, etc.). Some of these new consumption devices emit power quality disturbances, for example, harmonic emission. Harmonics and interharmonics will be high, below the frequency 2 kHz. Above 2 kHz, the emission is low over the whole spectrum which is generated by other equipment like energy efficient drives, micro-generators, and photovoltaic installations. The measurement of these low levels of harmonics at higher frequencies will be more difficult than for the existing situation with higher levels and lower frequencies.

• Interference between devices and power line communication
  Smart grids will facilitate communication between devices, customers, distributed generators, and the grid operator. Power-line communication might seem an obvious choice due to its easy availability, but choosing power-line communication could introduce new disturbances in the power system, resulting in further reduction in power quality. Depending on the frequency chosen for power-line communication, it may also result in diverged disturbances, interfering with radio broadcasting and communication. It is also true that modern devices can interfere with power-line-communication, either by creating a high disturbance level at the frequency chosen for power-line communication or by creating a low-impedance path, effectively shorting out the power-line communication signal.