Section 7 in Madhya Pradesh Electricity Grid Code (Revision-II), 2019
7. Section 7
Operational Planning7.1Introduction. - This section describes the process by which the SLDC carries out the operational planning and demand control procedures to permit reduction in Demand for any reason.7.2Objective. - The detailed provision is required to enable SLDC to achieve a reduction in demand to avoid Operating problems on all or part of the State Transmission System. SLDC will utilise Demand Control in a manner, which does not unduly discriminate against any one or group of customers.7.3Demand Estimation7.3.1The long-term demand estimation/load forecast (for more than 1 year) shall be done by the DISCOMs/MPPMCL in accordance with the provisions of Section 4. SLDC shall be provided with a copy of the same as and when it is finalised. Demand Estimation for period up to 1 year ahead shall be done by SLDC.7.3.2MPPMCL on behalf of Discoms shall provide to the SLOG their estimates of demand for the year ahead on month-basis for the next financial year by 15th November each year. Discoms shall also provide daily demand on weekly basis by last working day of previous week and monthly basis by 25th for the next month. The 15 minute block wise day -ahead demand estimates shall be provided by MPPMCL/DISCOMs to SLDC by 09.00 hrs of the current day.7.3.3Discoms shall provide to SLDC estimates of load that may be shed when required, in discrete blocks with the details of arrangements of such load shedding.7.3.4Discoms shall also furnish realistic category-wise demand for their respective companies along with details of essential loads, supply hours to be maintained in rural areas, details of power cuts imposed or to be imposed and specific requirements, if any.7.3.5The demand estimation shall cover active power as well as reactive power requirements fore casted for each substation.7.3.6The SLDC would update the demand forecast (in MW as well as MWh) on Daily/Weekly/Monthly basis, which would be used in the day-ahead scheduling.Attention shall also be paid by SLDC in demand forecasting for special days such as important festivals and National Holidays having different crests and troughs in the daily load-curve as compared to normal weather conditions & days.7.3.7DISCOMs/MPPMCL and SLDC would maintain a historical database for the purpose of Demand Estimation and shall be equipped with the state-of-the-art tools such as Energy Management System (EMS) for demand forecasting.7.3.8SLDC shall furnish data for and participate in deliberations of data for load generation balance or Annual Demand, availability and shunt capacitors requirement studies of WRPC. It shall take into consideration their reports for demand estimation.7.4Demand Control7.4.1Primarily the need for demand control would arise on account of the following conditions:• Variations in demand from the estimated or fore casted values, which cannot be absorbed by the grid, and• Unforeseen generation/transmission outages resulting in reduced power availability, and• Heavy reactive power demand causing low voltages.7.4.2SLDC shall match the consolidated demands of the Discoms with consolidated generation availability from SSGS, ISGS, IPP/CPP and other sources and exercise the Demand Control to ensure that there is a balance between the energy availability and the Discoms demand plus losses plus the required reserve.7.4.3SLDC would maintain a historical database for the purpose of Demand Estimation and shall be equipped with the state-of-the-art tools such as Energy Management System (EMS) for short-term demand estimation to plan in advance, as to how the load would be met without overdrawing from the grid.7.4.4SLDC shall advice STU for planning of Automatic load shedding schemes and rotational load shedding through installation of Under Frequency Relays.The guidelines for under frequency load shedding and df/dt relays shall be prepared, in accordance with the instructions from WRLDCNVRPC, by the Operation and Co-ordination Committee and shall be approved by the Grid Code Review Committee.7.4.5The particulars of feeders or group of feeders at a STU sub-station which shall be tripped under under-frequency load shedding scheme whether manually or automatic on rotational basis or otherwise shall be placed on Notice board and will also available at the sub-station for information of the consumer(s).7.4.6Demand control can also be exercised by the SLDC through direct circuit breaker tripping affected from SLDC using RTUs and under frequency detection by SLDC SCADA or through telephonic instructions. No demand shed by operation of under frequency relays shall be restored without specific directions from SLDC.7.4.7Rotational Load Shedding Schemes using Under Frequency Relay (UFR) shall be prepared time to time by the Utility in accordance with the guidelines/instructions issued by WRLDC/WRPC. The STU shall inform such decisions to MPERC with in seven days from the issue of instructions by WRLDC/WRPC.7.5Demand Disconnection. - (a) All users/distribution licensee shall initiate action to restrict the drawal of its control area from the grid, within the net drawal schedule.(b)All Users/distribution licensee shall ensure that requisite load shedding is carried out in its control area so that there is no over drawal.(c)The SLDC through respective Distribution Licensees shall also formulate and implement state-of-the-art demand management schemes for automatic demand management like rotational load shedding, demand response (which may include lower tariff for inter reptile loads) etc., to reduce over drawl in order to comply para 7.5 (a) and (b).(d)In order to maintain the frequency within the stipulated band and maintaining the network security, the inter reptile loads shall be arranged in four groups of loads, for scheduled power cuts/load shedding, loads for unscheduled load shedding, loads to be shed through under frequency relays/df/dt relays and loads to be shed under any System Protection Scheme identified at the RPC level. These loads shall be grouped in such a manner, that there is no overlapping between different Groups of loads. In case of certain contingencies and/or threat to system security, the RLDC may direct SLDC to decrease drawal of its control area by a certain quantum. Such directions shall immediately be acted upon by. Users/Distribution Licensees.(e)SLDC shall devise standard, instantaneous, message formats in order to give directions in case of contingencies and/or threat to the system security to reduce deviation from the schedule by the Users/Distribution Licensees/Injecting Utility at different overdrawal/Under Drawal/Over-Injection/Under Injection conditions depending upon the severity. The SLDC shall ensure immediate compliance of these directions and violation of SLDC's directions shall intimated to the Commission through monthly report.(f)All Users/distribution licensee shall comply with direction of SLDC and carry out requisite load shedding or backing down of generation in case of congestion in transmission system to ensure safety and reliability of the system. The procedure for application of measures to relieve congestion in real time as well as provisions of with drawl of congestion shall be in accordance with Central Electricity Regulatory Commission (Measures to relieve congestion in real time operation) Regulations, 2009.(g)The measures taken by the Users/Distribution licensee shall not be withdrawn as long as the frequency remains at a level lower than the limits or congestion continues, unless specifically permitted by the RLDC/SLDC.7.6Load Crash7.6.1In the event of load crash in the system due to weather disturbance or any other reasons, the situation would be controlled by the SLDC by the following methods.:(i)Backing down of hydel stations for short period immediately(ii)Lifting of the load restrictions, if any(iii)Exporting the power to neigh boring regions(iv)Backing down of thermal stations with a time lag of 5-10 minutes for short period(v)Closing down of hydel units (subject to non spilling of water and effect on irrigation)(vi)Backing down of Renewable Energy Power PlantsThe above methodology shall be reviewed from time to time in Operation and Co- ordination Committee.7.6.2While implementing the above, the system security aspects should not be violated as per relevant provisions under IEGC and the Grid Code. Further, in case of hydro generation linked with irrigation requirements, the actual backing down or closing down of such hydro units shall be subject to limitations on such account & to avoid spillage of water.
