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Power Supply Operating Standards

  1. OBJECTIVE

    These standards set in levels of operational security and quality of supply, which the Licensee shall be obliged to maintain in making power available for the purposes of supply to consumers, as laid down in Condition 20.5 of the Orissa Transmission and Bulk Supply License, 1997.

  2. OUTAGE PLANNING

    2.1 The generation out put shall be matched with estimated demand taking into account the Transmission/Generation outages so as to achieve the Transmission and Power Supply Security Standards. The Licensee shall abide by the relevant provisions in the GRID CODE to achieve coordination between Transmission Outage Programmes and Generation Outage Programmes.

  3. GENERATION SCHEDULE AND DESPATCH

    3.1 The Licensee shall take into account the following factors while preparing the Generation Schedule and Despatches.

    1. System Demand

    2. Merit Order Operation of Generating Units

    3. Availability of Generating Units

    4. Constraints on the Transmission System

    5. Security Requirements

    6. System Losses

    3.2 The Licensee shall accordingly prepare the Generation Schedule and their despatches on hourly day ahead basis, on the basis of data provided by Generators and CPP's and in consultation with ERLDC regarding allocated drawl for the day from Central Sector Generating Stations. The day ahead generation schedule shall be communicated to the Generators and ERLDC in the manner out lined in GRIDCODE.

    3.3 Total minimum spinning reserves of 5% of System Peak Load shall be achieved by making suitable allocations to specific generating stations in consultation with ERLDC.

  4. FREQUENCY MANAGEMENT

    4.1 The Licensee shall endeavour to run the system within a Frequency range of 49.5 to 50.5 Hz.

    4.2 The Licensee shall be vigilant when Frequency begins to rise above 50 Hz and initiate following measures to bring down the frequency to about 50 Hz.

    1. Check generation scheduling Vs. generation and request concerned Generator with excess generation to conform to generation schedule.

    2. Advise Hydro Stations to reduce generation without water spillage.

    3. Advise Coal Fired Thermal Stations having 210/500 MW units to back down to 'X' multiplied by the Load Factor (where 'X' is the generation of particular units during peak hours) but not to the extent requiring oil support.

    4.2.1 In case Frequency rises to 50.5 Hz inspite of above measures, the Licensee shall :

    1. Advise coal fired Thermal Stations having 210/500 MW units to bring down generation to bare minimum using oil support or if necessary to shut off 210 MW sets.

    4.2.2 In case the Frequency begins to rise above 50.5 Hz and does not fall below 50.8 Hz, the Licensee shall in consultation with ERLDC Island its system from rest of EREB if there is Import at points of interconnections.

    4.3 The Licensee shall be vigilant when Frequency begins to fall below 49.5 Hz and initiate following measures to raise the System Frequency to about 50 Hz.

    1. Check generation scheduling Vs. generation and request concerned Generator with less generation to conform to generation schedule.

    2. Check whether there is any excess drawl at any points of interconnection by any Distribution and Retail Supply License and advise to restrict its drawl within Schedule.

    3. Advise Hydro Stations to synchronise stand by machines, if available.

    4.3.1 In case the Frequency still falls and reaches 49.0 Hz the Licensee shall advise Distribution Licensees to shed load manually in predetermined blocks.

    4.3.2 In case the Frequency still continues to fall and reaches 48.5 Hz, the Licensee shall in consultation with ERLDC Island its system from rest of EREB if there is Export at points of interconnection.

  5. STANDARDS TO BE MET BY GENERATORS

    5.1 Licensee, while contracting Bulk Power Supply from Generators shall specify, voltage and frequency standards with limits of variation in the Power Purchase Agreement, which the Generator has to accommodate.

    5.2 Licensee shall incorporate conditions in the Power Purchase Agreement requiring the Generators to commit :

    1. Spinning Reserve Response during Frequency transients at different load levels.

    2. Reactive power capability (MVAR).

    3. Economic back down level.

    4. Loading increment rate from back down level to maximum continuous Rating (MW/min).

    5. Loading decrement rate from maximum continuous rating to back down level (MW/min).

    6. Pick up rates on synchronising in MW under conditions :

      1. Cold start

      2. Warm start

      3. Hot start

    7. the extent that it does not jeopardise safety of its plant and personnel.

  6. GENERATION RESERVE

    6.1 The Licensee shall plan for necessary capacity and Energy reserves in accordance with Security Standards.

    6.2 These reserves shall be allocated to the Generators in the following manner :
    Contingency Reserve : on month ahead basis
    Spinning Reserve : on day ahead basis

  7. MONITORING OF GENERATION

    7.1 The Licensee shall provide facilities at SLDC for receiving following real time data from Generators :

    1. Frequency

    2. MW output

    3. MVAR output

    4. MW and MVAR flow in outgoing lines

    5. Voltage at interconnection Bus

    7.2 The Licensee shall establish procedure for monitoring the following parameters of a generation plant :

    1. Declared Gross Generation Capacity

    2. Loading rate of a Unit

    3. De-loading rate of a Unit

    4. Active and Reactive power delivery following Despatch instructions

    5. Capability of Generating plant to meet Spinning Reserve requirements.