Before the

MAHARASHTRA ELECTRICITY REGULATORY COMMISSION World Trade Centre, Centre No.1, 13th Floor, Cuffe Parade, Mumbai – 400 005 Tel. No. 22163964/ 65/ 69 Fax 22163976 Email: [email protected] Website: www.mercindia.org.in Case No. 91 of 2007 In the matter of Petition of Suzlon Power Infrastructure Ltd. seeking clarification/ amendment in the Terms and Conditions of Tariff Regulations 2005 with respect to design of 220 kV and 132 kV transmission lines with reference to wind energy sector. Dr. Pramod Deo, Chairman Shri. A. Velayutham, Member Shri. S. B. Kulkarni, Member

ORDER Dated: April 15, 2008 M/s. Suzlon Power Infrastructure Ltd. (SPIL) filed a Petition on January 16, 2008 seeking clarification / amendment in the MERC (Terms and Conditions of Tariff), Regulations, 2005, related to design of 220 kV and 132 kV transmission lines pertaining to the wind energy sector. 2.

The prayers made by the Petitioner are as follows: (1) Accept the Petition in the matter of clarification / amendment in the Terms and Conditions of Tariff Regulation 2005 with respect to design of 220 KV and 132 KV transmission lines with reference to wind energy sector; (2) Modify / Amend its terms and Conditions Regulations 2005 with respect to design of 220 KV and 132 KV transmission lines with reference to wind energy sector; (3) Allow loading of the Transmission lines using ACSR Panther conductor up to 440Amp and ACSR Zebra Conductor up to 700 Amp as per column 5 of Table II A above; (4) Not to insist N-1 criteria for exclusive transmission of electricity from Wind farms.

Since this matter Commission directed the accompaniments (both in Maharashtra State Power

required the views of the immediate stakeholders, the Petitioner to serve copies of its Petition along with its hard and soft versions) to all the Distribution Licensees; Generation Company Ltd. (MSPGCL); State Transmission

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Utility (STU), and the four consumer representatives authorised on a standing basis under the Electricity Act, 2003 (“EA 2003”). The Commission further directed the Distribution Licensees, MSPGCL and STU to file their reply to the said Petition on affidavit, if any, with a copy endorsed to the Petitioner and to the four consumer representatives. Hearing in the matter was scheduled by the Commission on March 25, 2008. 3. At the hearing held on March 25, 2008, Shri. Atul Shah and Shri S V Deo appeared for the Petitioner (M/s SPIL). Shri. V.T. Phirke represented the STU. At the outset, M/s SPIL submitted that the Surge Impedance Loading (SIL) values specified in the MERC (Terms and Conditions of Tariff), Regulations, 2005 at Appendix II are not in line with the “Manual on Transmission planning criteria” issued by the CEA in June 1994 as these values are not applicable to short lines. 4. During the hearing, it was observed by the Commission that the SIL values specified at Appendix II of the said MERC (Terms and Conditions of Tariff), Regulations, 2005 were for calculation of transmission system availability, which was in line with the “Central Electricity Regulatory Commission (Terms and Conditions of Tariff), Regulations, 2004”. In accordance with Section 61 of the EA 2003, the Commission is required to be guided by the principles and methodologies specified by the CERC for determination of the tariff applicable to generating companies and transmission licensees. Hence, the SIL values are used for applying the incentives based on transmission system availability. Therefore, M/s SPIL should not relate these values with SIL limits specified in Manual on Transmission planning criteria issued by the CEA in June 1994. Consequently, the issues raised by M/s SPIL with respect to design of 220 KV and 132 KV transmission lines with reference to wind energy sector would not require effecting any amendment to the MERC (Terms and Conditions of Tariff) Regulations; 2005. The other issues raised in the Petition are dealt with in the following paragraphs : 5.

Loading Limit: Regarding the issue of permissible loading limit of the transmission lines installed for evacuation of Power from the generating stations, M/s SPIL read out paragraph 6 of its Petition, which is in respect of CEA Manual on Transmission Planning Criteria – Section 4: “Permissible line loading Limits”. The same is reproduced below: “Permissible line loading Limit depends on many factors such as voltage regulation, stability and current carrying capacity (thermal capacity) etc. While Surge Impedance Loading (SIL) gives a general idea of the loading capability of the line, it is usual to load the short line above SIL and long lines lower than SIL ( Because of the stability limitations). SIL at different voltage level is given at Annex-II. Annex-II also shows line loading (in terms of surge impedance loading of uncompensated line) as a function of line length assuming voltage regulation of 5% and phase angular difference of 30 0 between the two ends of the line. In case of shunt compensated lines, the SIL will get reduced by a factor K, where K = (1-degree of compensation )-1/2

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For lines whose permissible line loading as determined from the curve is higher than the thermal loading limit, permissible loading limit shall be restricted to thermal loading limit.” 6.

Redundancy Criteria: M/s SPIL requested for a clarification regarding applicability of redundancy criteria in the network i.e. (N-1) redundancy condition, to the transmission lines used for evacuation of Wind Energy. It was submitted that as per the CEA guidelines, under steady State operation, the EHV Grid System should be capable of withstanding without necessitating load shedding or rescheduling of generation the following contingencies: v Outage of a 132 kV Double Circuit line; or v Outage of a 220 kV Double Circuit line.

7. As per M/s SPIL, if one transmission line circuit goes out, the other transmission line circuit would be adequate for power evacuation as the Double Circuit transmission lines are designed with built-in redundancy accordingly. As per M/s SPIL, healthiness and availability of one transmission line, in the event of the loss of a single transmission line from a double Circuit transmission network is enough to meet out the (N-1) redundancy condition as against the requirement of one complete Double Circuit to be kept redundant. 8. M/s. SPIL further submitted that 2.5 times of the SIL loading can be accommodated on the transmission line in case of contingencies because wind energy generation which is an infirm power, has its peak period during the monsoon months of June-July-August. It is known that during these periods, the ambient temperature is low, and heat dissipation from the current carrying conductors is better facilitated by the winds. As a result, these parameters permit more ampacity (ampere capacity) within the limits of Thermal loading of the lines. M/s. SPIL further requested the Commission to issue directive to raise permitted line loading to 700 Ampere and 400 Ampere for ACSR Zebra and Panther Conductors, respectively. M/s SPIL submitted that Ampere should be the basic criteria for designing the transmission lines as the Ampere flow is responsible for the temperature rise. M/s. SPIL further explained that the wind power generation projects, generally, are at the periphery of the Intra-state transmission system (grid) and these are radially connected through transmission lines to the Intra-state transmission system. Hence, the main network parameters of the Intra-state transmission systems are not much influenced by the contingencies on the Wind power evacuation system. 9. The Commission enquired with Shri V.T. Phirke who represented the STU at the hearing, Shri Prashant Joshi who was present on behalf of The Tata Power Company Ltd and Shri B.S. Chaudhari who was present on behalf of The Reliance Energy Ltd., regarding their views pertaining to the issues raised by M/s SPIL. However, the representatives of the STU and the other utilities submitted that copy of the Petition was received by them only on 24th March, 2008 and hence, they were not in a position to comment on the same due to paucity of time.

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10. The Commission is of the view that two main issues emerge from the submissions made by M/s. SPIL, that is (i) to allow line loading more than SIL for short lines and (ii) relaxation in the (N-1) redundancy criteria in respect of wind power evacuation projects. The Commission is of the view that both these items are governed by Grid standards and the standards for construction of transmission lines, which are dealt with by the CEA in line with section 34 and section 73(b) of EA 2003. The Commission is of the view that the STU is supposed to discharge all functions of planning and co-ordination related to Intra-State Transmission system with the CEA / CTU / Transmission Licensees / Generating Companies (including Renewable Energy Projects) etc., in accordance with section 39(2)(b) of the EA 2003. 11. The Commission observes that the issue of Line loading above SIL has already been addressed in the CEA’s manual on Transmission Planning criteria where it is stated that “…. it is usual to load the short lines above SIL…… permissible loading limit shall be restricted to thermal loading limit” It should also be noted that, for such loading above SIL limits, the need for providing reactive compensation, if called for, to avoid possible voltage drops should be addressed after conducting the required studies. Higher SIL may be permitted only after taking into account the capability limits of the conductors based on present observations of relevant National / International bodies. 12. The Commission further observes that in case of (N-1) redundancy condition, the STU may arrive at appropriate decision in consultation with the CEA. For Renewable Energy Generation Project, general specifications which are directed for the conventional transmission systems may not be applicable to these transmission lines and specific conditions need to be considered after due evaluation, keeping in mind their limited impact on the Intra-state transmission network. 13. In this context, the directives given by the Commission in its Order dated November 13, 2007, in the matter of “In principle approval to Maharashtra State Electricity Transmission Company Limited for development of infrastructure facilities to enable evacuation of power” (Case No. 34 of 2007), are relevant to be quoted as below: Item 29. “As outlined under earlier paragraphs, the Evacuation Arrangement including transmission lines for evacuation of power from generating station forms part of the Intra-State Transmission system. In this regard, the Commission further clarifies that being part of InSTS, the expenditure incurred for development of such transmission infrastructure shall form part of total transmission system cost of InSTS independent of who develops such transmission infrastructure. The same shall be recovered in accordance with the principles outlined under Transmission Pricing Framework Order of the Commission. Thus, question of differential treatment for evacuation arrangement for generating stations depending on ownership of the generating station does not arise, so long as generating station uses state transmission network for wheeling power to distribution licensees or open access users within State.”

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14. As elaborated under Paragraph 24 and 25 of the Commission’s Order dated November 13, 2007 (Case 34 of 2007) as well as under Regulation 8.6 and 8.7 of MERC (Transmission Open Access) Regulations, 2005, the Commission reiterates that as per Section 39(2)(b) of EA 2003, MSETCL in its capacity as STU is responsible for development of State-wide Transmission System Plan and to ensure co-ordinated development of intra-State transmission system. In fact, the Planning Code and Planning Criteria outlined under relevant Regulations 8 and 9 of “MERC (State Grid Code) Regulations, 2006 shall form the basis for STU to discharge its statutory function of planning. 15. Further, as per Section 86(1)(e) of EA 2003, the Commission is obliged to promote generation from renewable energy sources by providing suitable measures for connectivity with the Grid for such renewable energy sources. Accordingly, the Commission advises the STU that while applying norms for Renewable Energy Sources, it should be borne in mind that the project for evacuation arrangement should be financially feasible and capital expenditure burden should be optimum, which in turn, will benefit the consumers and help in promoting Renewable Energy Projects. However, the Commission cautions that in no case the technical and safety requirements should be diluted and that there should be sufficient flexibility to consider the specific conditions. 16. During the hearing, the STU had submitted that they had not evaluated the above aspects associated with the development of evacuation arrangement for renewable energy sources. The Commission therefore directs STU to evaluate the issues pertaining to (a) Loading limits; and (b) Redundancy criteria, applicable to the short transmission lines evacuating the Wind power, which are presented by M/s SPIL. The Commission further directs STU to explore the appropriate solution and communicate to the petitioner within six weeks time from issuance of this Order, under intimation to the Commission. With the above observations and directions, Case No. 91 of 2007, stands disposed of.

Sd/(S.B.Kulkarni) Member

Sd/(A. Velayutham) Member

Sd/(Dr. Pramod Deo) Chairman

(P.B.Patil) Secretary, MERC

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