POWER SYSTEM CONTROLObjectiveThe objectives of Power System Control remains as previously broadly defined.GeneralGeneral Power System control activities include:Network Planning and DevelopmentManual Network Switching Automatic Network Switching

The System Operator may not always be able to pre inform users about system control activities, especially in those instances when protection relay and other emergency developments result in network switching.

*

POWER SYSTEM CONTROLPower System Control ActionsThe System Operator shall be responsible for operation of the Power System securely and reliably at all times, ensuring prompt and appropriate remedial action during all abnormalities. This he does via:Consultation with users.Network Switching for: planned and emergency Transmission equipment outagesVoltage Control and Limitation of Power flows on the transmission system to levels consistent with equipment capabilities.The System Operator shall identify control actions required.The System Operator shall establish all automatic switching sequences required.

*

POWER SYSTEM CONTROLNotification to all UsersThe System Operator shall notify all Transmission Network users of planned control actions, in accordance with the grid connection agreement, where time permits.Control under fault or emergency conditionsThe System Operator shall ordinarily inform users of control actions after occurrence.Generating companies shall also promptly inform the System Operator of the tripping of a generating unit with reasons adduced.The System Operator shall inform users on likely duration of these conditions and when they have ceased.

*

POWER SYSTEM CONTROLDe-energisation of plantThe System Operator shall de-energise a generating unit if he identifies the appropriate causes, especially as listed in the connection agreement.Operating procedures including Fault ReportingThe System operator shall develop and maintain operating procedures for the safe operation of the Transmission network and for assets connected to the network that shall be complied with by all users.Each user shall be responsible for his own safety rules and procedures and ensure that they are compatible with the System operator procedures.Users shall enter into operating agreements with the System Operator as defined in the grid connection agreement.

*

POWER SYSTEM CONTROLOperating procedures including Fault ReportingFault reporting and analysis/incident investigation shll be carried out as follows:Generator operators shall report all change of status of generating plant within 15 minutes.In event of multiple trip the user shall:Submit a written report to the System Operator within 1month.In addition he shall provide a full report as per the grid code. This shall be treated as a major incident.Distribution operators and grid connected end use customers shall report loss of all loads >10MW to the System operator within 10 minutes and notify him of reconnection not later than 15 minutes after,Network Sabotage incidents shall be reported to the System OperatorThe System operator shall investigate any incidences that affect supply quality to another user as detailed in the grid code

*

FREQUENCY CONTROL AND OPERATING RESERVEObjectiveGeneralFrequency limitsFrequency ControlComponents of Operating ReserveOperating Reserve policyAmount of Operating ReserveOperating Reserve Procurement

*

FREQUENCY CONTROL AND OPERATING RESERVEObjectiveTo specify the System Operator requirements for ensuring provision of Frequency control capability.To specify mandatory Operating reserve and Reliability must run requirements of the System operator.GeneralUse of primary or secondary frequency control for ensuring frequency is kept within applicable limits.Use of operating reserve on generators operated on frequency sensitive mode through ancillary services agreements.

*

FREQUENCY CONTROL AND OPERATING RESERVEFrequency limitsGrid Frequency shall be 50HzOperating band +0.5% of 50Hz 90% of the time.Under System stress +2.5% (48.75 51.25)Frequency ControlNormal Conditions Use of Spinning Reserves.Managing Shortfalls.Components of Operating ReserveTwo types of Operating ReservesQuick Reserve (Spinning Reserve [Primary & Secondary] & Emergency Reserve)Slow Reserve (Hot standby & Cold standby)

*

FREQUENCY CONTROL AND OPERATING RESERVEOperating Reserve policyReserve type mix options in practical operations as policy to be approved by NERCRelevant factors to be considered in developing reserve policy. Premises under which Operating Reserve policy shall be developed. (Primary Reserve, Spinning reserve, Minimum Operating reserve, Operating reserve mix & System spread of operating reserve)Annual review of Operating reserve policy Records keeping by System operator of significant alterations to Operating reserve policy.

*

FREQUENCY CONTROL AND OPERATING RESERVEAmount of Operating ReserveSystem operator roles in determination of magnitude and content of total Operating reserve.Generator responsibilities on plant availability information to System operator.Transmission resources and weather information records keeping by System Operator for future load prediction.Managing errors in load forecasting in the use of operating reserveOperating Reserve ProcurementUse of Ancillary services for ensuring Operating reserve procurement during pre transition, Transition, Medium term and final stages of the electricity market.

*

VOLTAGE CONTROLObjectiveAchieving healthy Transmission system voltage profile.GeneralSystem operator roles in the dispatch of reactive power all over the grid towards ensuring appropriate voltages all over the grid.Voltage ControlScope of System Operators responsibilities in dispatch instructions and control facilities adjustment towards maintaining proper voltages at all points of the grid including interconnection points.Remedies and penalties management regarding user non compliance.

*

VOLTAGE CONTROLVoltage Control policyTransmission System losses ManagementUse of Operating Procedures in Voltage controlVoltage Control methodsApproved voltage control methodsContinuous Monitoring of System voltages by System OperatorVoltage Control during emergenciesApproved additional voltage mechanisms t be utilized in System emergency conditions.Provision of voltage control

Use of Ancillary services for procurement for voltage control during pre transition, Transition, Medium term and final stages of the electricity market.

*

BLACK STARTObjectiveTo stipulate the black start requirements the System Operator has to cater forGeneralIdentifying generators that can start themselves and other generators on the grid after a total shut down. Rules and contracts needs for ensuring this is put in placeAncillary ServiceProcurement of Black start as an ancillary service.RequirementsRequirements for black start stations that must be set out by the System Operator

*

EMERGENCY OPERATION AND RESTORATIONObjectiveOutline general restoration strategy to be adopted by the System operator following a partial or total shutdown of the grid SystemGeneralClarification of the various operating states of the grid system (Normal, Alert, Emergency extreme & Emergency restorative states)Emergency operationResponsibilities of the System Operator whenever the system shifts out of the normal operating state.System operator responsibilities including putting in place of procedures to ensure minimum emergency requirements of all users of the grid.

*

EMERGENCY OPERATION AND RESTORATIONRestoration of supplyDevelopment and maintenance of well documented power system restoration plan by the System OperatorTraining needs and requirements of system operators personnel.In extreme operating state mock test with all stakeholders once a year.Back-up Control CentrePlan for permanent fully staffed control center that can take over seamlessly in event NCC becomes inoperable.Staff of the back up control centre shall be well trained.

*

EMERGENCY OPERATION AND RESTORATIONEmergency co-ordination facilityThe System operator shall provide a permanent emergency coordination facility as part of the restoration plan.This facility shall contain minimum communications capability needed for operating the system in event of simultaneous failure of both the NCC and the backup control centre.Basic capability listing of the emergency coordination facilityUnder Frequency Load sheddingPolicy & Analysis Under frequency load shedding schemeCoordination TestingManual Load shedding Re-Synchronization.

*

OPERATIONAL PLANNINGObjectiveTo specify plans to be applied by the System operator to ensure proper system operations in the short and medium term.GeneralActivities to be performed include Data base creation, compilation of minimum and peak load models for present year and 5 years ahead, load flow and fault level case studies.Other contingency plans including under frequency case studies.Proper documenting of these plans and placement in the national control room.Transmission reinforcement and expansion studies to accommodate new operating conditions and users

*

OPERATIONAL PLANNINGFunctions of the Operational Planning staffDevelopment of operational plans, Maintenance of plans, Implementation of plans, Information and Training, Annually review under frequency load shedding scheme.The staff shall be experienced in operation and planning of power systems with appropriate skills in Technical operational studies.Data required for Medium Term and operational PlanningAll users to provide by week 32 of each year the following dataMaximum Demand profiles per connection pointActive and Reactive power profilesDay ahead demand forecasts,System operator to develop a demand forecast methodology that follows specific times as stipulated in grid code and market rules

*

OPERATIONAL PLANNINGActual Demand Control dataData to be supplied by distribution network operators and grid connected end users daily.ConnectionsNew connection notification information details to System operator by users.Changes to Information Already SuppliedAll users must update the system operator in writing on every change to information previously supplied. Monthly and weekly confirmation criteria.Timing and publicationDay ahead forecast demand for the entire system shall be published daily at 11.00hrs.

*

INFORMATION EXCHANGEObjectiveGeneralRequirement to notifyNotification of an operationForm of notification of an operationRecording of an operationTiming in respect of an operationNotification of eventsForm of notification of an event

*

*

*

*

*

*

*

*

*

*

*

*

*

*

*

*

*

*

*

*

*