The Rajasthan Electricity Regulatory Commission (RERC), in a recent order, has rejected the compensation claims by a solar developer for losses incurred due to voltage fluctuations and directed them to make necessary arrangements for injecting or withdrawing reactive power per the Electricity Authority (regulations outlined by the Central CEA).
The Commission also directed the Rajasthan Rajya Vidyut Prasaran Nigam (RVPN), the state load dispatch centre (SLDC), and the solar developers to take appropriate and necessary action to maintain the grid voltage within the operating limits for 200 MW (2*100 MW) solar power projects at the Bhadla Solar Park in Rajasthan.
The respondents included RVPN, SLDC, Saurya Urja Company of Rajasthan, Northern Regional Load Despatch Centre, Northern Regional Power Committee, and the Solar Energy Corporation of India (SECI).
ACME Solar Holding formed two special purpose vehicles (SPVs), namely ACME Jodhpur Solar Power and ACME Rewa Solar Energy, for the development of a 100 MW solar power project by each SPV at the Bhadla Solar Park, Phase-III in Rajasthan.
The projects supply power through a dedicated line connected to the Saurya Urja Company of Rajasthan’s 33/200 kV pooling substation, which is the interconnection point of the projects with the grid.
The pooling substation is connected to RVPN’s 400/220 kV grid substation through two 220 kV transmission lines. According to the submissions of the solar developers, there have been severe voltage fluctuations in the Bhadla power sub – station since the year 2018 which have led to abnormal tripping of solar inverters, damaging electrical components, and reducing the generation of power. These continuous issues of power voltage fluctuations have also led to disruption of the process of electricity generation and prevented the sub-station from reaching its maximum capacity.
It was also contended by the petitioners that due to the absence of a reliable and secure system of transmission, there have been instances of low voltage, for which the accountability rests with the RVPN and SDLC.
Even though numerous requests and reminders about the disturbances in the electricity grid which even included tripping of voltage at the sub – station, RVPN and SLDC did not undertake any measures for resolving the issues. Hitachi Energy India was also engaged by the petitioners in order to conduct an analysis regarding the steady – state of electric grid and determine the reasons resulting in low voltage. According to the report filed by Hitachi, the major reason behind consistent tripping was issues at the Bhadla grid – substation.
It was also mentioned by the RVPN on numerous instances that the generator had resulted in a failure to provide any kind of reactive power for supporting the grid when the issue of low voltage was faced. Secondly, Saurya Urja Company of Rajasthan also submitted its stance that post consideration of the consistent issues of over or under – voltage, the commission should take desired steps for instructing RVPN to install STATCOM for enhancing the grid voltage during the peak generation hours which would further prevent the solar generators from experiencing any energy loss or tripping of inverters. Additionally, it was also requested that the installation of two 25 MVAr shunt reactors should be undertaken in order to maintain voltage conditions at the pooling sub – station which shall be connected to the main bus along with associating development costs which shall be borne by the solar power developers.
It was observed by the commission that dynamically varying support from the generators was essential for ensuring a stable level of voltage, which along with reactive power control would phenomenally impact the stability of the system, and any imbalance of the reactive power would lead to instability of the voltage.
It was also noted by the state regulator that RVPN and Saurya Urja Company of Rajasthan which reported real-time reactive power injection and absorption support from the generation in the periods of under or over-voltage conditions failed to meet the CEA Regulations requirements. Moreover, a direction was made to the RVPN for ensuring that the sanctioned strength of +300MVAR, 400kVSTAT COM at 400kV GSS Bhadla, and +100MVAR, 200kV STATCOM at 220 kVGSS Phalodi is maintained.
According to the CEA, every generating station should be equipped with the capability of ensuring a dynamic supply of varying reactive power support for maintaining power factor within the permitted limit of 0.95 lagging to 0.95 leading. Since, in the present case, most of the responsibility was also shared by the petitioners, no grant of compensation was made.