Standards for Transmission Licensee

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 19.4(a) of the Haryana transmission and Bulk Supply License, 1999.

The generation output 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 provisions in the GRID CODE shall be followed to achieve coordination between Transmission Outage Programme and Generation Outage Programme.

3.1 The following factors shall be taken into account while preparing the Generation Schedule and Despatches.

However, the System Security and Stability shall have precedence over and above the merit order of operation.

3.2 The Generation Schedule and their despatches shall be accordingly prepared on 15 minute block day ahead basis, on the basis of data provided by Generators and CPP's and in consultation with NRLDC regarding allocated drawal for the day from Central Sector Generating Stations. The day ahead generation schedule shall be communicated to the Generators and NRLDC in the manner out lined in GRIDCODE.

3.3 Appropriate spinning reserve shall be achieved by making suitable allocations to specific generating stations in consultation with NRLDC.

4.1 The system shall normally be maintained within a Frequency range of 49.5 to 50.5 Hz by adhering to the following steps:

i) Licensee shall regulate the load/own generation under its control so that it may not draw more than its net drawal schedule during low frequency conditions and less than its drawal schedule during high frequency conditions.

ii) In case licensee is likely to face power shortage situation despite requisitioning its full entitlement from Central sector, it shall endeavor to enter into a bilateral agreement with the other state constituents having a power surplus and vice-versa. In any case, during low frequency conditions licensee would not resort to overdraw.

iii) Sudden reduction in generator output by more than one hundred (100) MW except in an emergency condition or to prevent an imminent damage to the equipment shall not be carried out without prior intimation and consent of the NRLDC, particularly when frequency is falling below 49.0 Hz.

iv) Sudden increase in load by more than 100 MW by the licensee, particularly when frequency is falling below 49.0 Hz and reduction in load by such quantum when frequency is rising above 50.5 Hz shall not be carried out without prior intimation and consent of the NRLDC.

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.

i. Check generation scheduling vs generation and request concerned Generator with excess generation to conform to generation schedule.

iii. Back down thermal stations to the extent of norms decided by NRLDC/NREB from time to time.

4.2.1 In case Frequency rises to 50.5 Hz. inspite of above measures, the coal fired Thermal Stations having 210/500 MW units shall be advised to bring down generation to bare minimum using oil support or if necessary to shut off below 210 MW sets.

4.2.2 In case the Frequency still rises above 50.5 Hz and does not fall below 50.8 Hz, the system shall be islanded, in consultation with NRLDC, from rest of NREB if there is import at points of interconnections. However before doing so all efforts would be made so that no part of the grid is deliberately isolated from the rest of the Regional Grid, except (i) under an emergency, and condition in which such isolation would prevent a total grid collapse and/or enable early restoration of power supply, (ii) when such isolation is specifically instructed by NRLDC. Complete synchronization of grid shall be restored as soon as the condition again permits it. The restoration process shall be supervised by NRLDC, as per operating procedure separately formulated.

4.3 When Frequency begins to fall below 49.5 Hz following measures should be initiated to raise the System Frequency to about 50 Hz.

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

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

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

4.3.2 In case the Frequency still continues to fall and reaches 48.5 Hz, the system shall be islanded, in consultation with NRLDC, from rest of NREB if there is export at points of interconnection.

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

5.2 The following conditions shall be incorporated in the Power Purchase Agreement requiring the Generators to commit:

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

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

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

g. that the generator shall abide by the provisions in GRID CODE to the extent that it does not jeopardise safety of its plant and personnel.

5.3 (i) Free Governor Mode of Operation: Licensee would ensure that the generating units synchronized with the grid are operated on free governor mode of operation and with necessary primary and secondary control in line with relevant sections of IEGC.

(ii) AVRs Control: All generating units shall normally have their Automatic Voltage Regulators (AVRs) in operation, with appropriate settings. In particular, if a generating unit of over fifty (50) MW size is required to be operated without its AVR in services, the NRLDC shall be immediately intimated about the reason and duration, and its permission obtained. Power System Stabilser (PSS) in AVRs of generating units (wherever provided) shall be properly tuned as per a plan prepared for the purpose by the Central Transmission Utility (CTU) from time to time. CTU will be allowed to carry out tuning/checking or PSS wherever considered necessary.

6.1 The necessary capacity and energy reserves shall be planned for in accordance with Security Standards.

6.2 These reserves shall be allocated to the Generators in the following manner:

Contingency Reserve (i.e. The operating reserve, which will respond to the disturbance condition following the most severe single contingency.)	On month ahead basis
Spinning Reserve (i.e. the operating reserve, which will automatically respond to the frequency deviation.)	on day ahead basis

7.1 The SLDC shall be equipped to receive the following real time data from Generators:

7.2 A procedure shall be established for monitoring the following parameters of a generation plant :