Chapter- 9
RECOMMENDATIONS
9.1 Review of Protection Systems
9.1.1 There is a need to review protection schemes. This Committee concurs with recommendation of previous enquiry committees that a thorough third party protection audit need to be carried out in time bound manner. This exercise should be repeated periodically and monitored by RPCs.
Action: RPCs, CTU, STUs
Time Frame: 1 year
9.1.2 Till protection audit is taken up, there is need to take immediate review of zone-3 philosophy in particular. Techniques are available to modify characteristics of the relay so that it can distinguish between load encroachment and faults. These techniques and other alternatives should be explored immediately.
Action: RPCs, CTU, STUs
Time Frame: Immediate
9.1.3 The application of synchrophasor measurements from PMUs should be explored for protection systems. There is also an urgent need to deploy Special Protection System (SPS) in critical transmission elements. Also there is need to make already approved SPS operational.
Action: RPCs, CTU
Time Frame: 1 year
9.1.4 A complete independent audit of time synchronization of DRs, ELs and PMUs should be carried out.
Action: Generators, CTU, STUs
Time Frame: 1 month
9.2 Frequency Control through Generation reserves/Ancillary services
9.2.1 Frequency band needs to be further tightened and brought close to 50 Hz. POSOCO may file an urgency application in Supreme Court for early resolution of the issue in view of the recent grid disturbances.
Action: POSOCO
Time Frame: 1 month
9.2.2 A review of UI mechanism should be carried out in view of its impact on recent grid disturbances. Frequency control through UI may be phased out in a time bound manner and Generation reserves/Ancillary services may be used for frequency control. Appropriate regulatory mechanism needs to be put in place for this purpose. POSOCO should take up the matter with CERC.
Action: POSOCO
Time Frame: 3 months
9.3 Ensuring proper functioning of defense mechanism
All STUs should immediately enable under frequency and df/dt based load shedding schemes. Central Commission should explore ways and means for implementation of various regulations issued under the Electricity Act, 2003. Any violation of these regulations can prove to be costly as has been the case this time. RPCs need to take up the matter for compliance. In case non-compliance persists, POSOCO should approach Central Commission.
Action: STUs, RPCs, POSOCO
Time Frame: Immediate
9.4 Ensuring primary frequency response from generators
All out efforts should be made to implement provisions of IEGC with regard to governor action. Central Commission needs to look into ways and means to hasten implementation of provisions of IEGC including that on governor action. POSOCO need to take up the matter with Central Commission.
Action: POSOCO
Time Frame: 3 months
9.5 Revising Total Transfer Capability (TTC) based on change in system conditions
9.5.1 POSOCO should take up with Central Commission the issue of inconsistency between Congestion regulation and the detailed procedure framed there under so that congestion due to forced outages and Unscheduled Interchange (UI) can be handled effectively.
Action: POSOCO
Time Frame: 1 month
9.5.2 NLDC and each RLDC should have one real-time security desk in all the shifts to be manned by engineer capable of carrying out TTC calculations. To facilitate this, manpower at NLDC and RLDCs need to be enhanced with regulatory support to take care of financial aspects. Till this arrangement can be firmed up, various scenarios of outages could be built, which then can be used by despatcher in real time. Faster algorithm for calculation of TTC may be adopted by the load despatchers to update it in real time under outage conditions.
Action: POSOCO
Time Frame: 6 months
9.6 Coordinated outage planning of transmission elements
Outage planning of inter-State and inter-regional transmission elements should be carried out in a coordinated manner at RPC fora (say Operation Co-ordination sub-committee of RPCs) in accordance with regulation 5 of Central Electricity Authority (Grid Standards) Regulation, 2010 and Section 5.7.1 of Indian Electricity Grid Code. In case need for emergency maintenance arises in between two meeting of Operation Co-ordination sub-committee, NLDC and RLDCs should allow such maintenance after carefully looking at prevailing system conditions under intimation to RPC Secretariat.
Action: RPCs
Time Frame: Immediate
9.7 Reactive power planning
In order to avoid frequent outages/opening of lines under over voltages and also providing voltage support under steady state and dynamic conditions, installation of adequate static and dynamic reactive power compensators should be planned.
Action: CEA, CTU, STUs
Time Frame: 6 months
9.8 Review of penal provisions of the Electricity Act, 2003
The powers of Load Despatch Centres and Regulatory Commissions related to non-compliance of statutory/regulatory provisions including that for non-compliance of directions and non-payment of UI charges, need review. Appropriate amendments need to be carried out in the Electricity Act, 2003 after such review.
Action: Ministry of Power, Govt. of India
Time Frame: 6 months
9.9 Optimum utilization of available assets
9.9.1 The regulatory provisions regarding absorption of reactive power by generating units needs to be implemented.
Action: POSOCO
Time Frame: Immediate
9.9.2 An audit of devices such as HVDC, TCSC, SVC and PSS should be done immediately to ensure that their stability features are enabled. Further, exercise of PSS tuning should be planned and implemented. Settings of these dynamic stabilizing devices should be reviewed at appropriate intervals.
Action: CTU, STUs, Generators
Time Frame: 6 months
9.9.3 Functioning of existing PMUs and availability of their output to RLDCs and accuracy of time synchronization should be monitored on daily basis and, if required, corrective actions should be taken on priority basis.
Action: CTU, POSOCO
Time Frame: Immediate
9.10 Deployments of WAMS
9.10.1 The synchrophasor based WAMS employing PMUs offer a wide applications for real time monitoring and control of the system, specially under the dynamic conditions. Adequate number of PMUs should be installed to improve the visibility and real time monitoring of the system. Further the applications related to the synchrophasor based wide area monitoring, protection and control should be embedded in the system.
Action: CTU
Time Frame: 1 year
9.10.2 Possibility of voltage collapse prediction, sensing global power system conditions derived from local measurements may be explored.
Action: RPCs
Time Frame: 1 year
9.11 Need of Dynamic Security Assessment and review of State Estimation
In order to assess the system security in real time and assess the vulnerability condition of the system, dynamic security assessment need to be periodically carried out at the control centers. A proper review and upgradation of the state estimation procedure is required to improve the visibility and situational awareness of the system.
Action: POSOCO
Time Frame: 6 months
9.12 Implementation of islanding schemes
Efforts should be made to design islanding scheme based on frequency sensing relays so that in case of imminent grid failure, electrical islands can be formed. These electrical islands can not only help in maintaining supply to essential services but would also help in faster restoration of grid.
Action: CEA, RPCs, POWERGRID, STUs, SLDCs and Generators
Time Frame: 6 months
9.13 Autonomy to Load Despatch Centres
9.13.1 As National Grid is on the horizon, homogenization of system operation philosophy is need of the hour. The present organizational set up of Load Despatch Centres need to be reviewed. System operation needs to be entrusted to Independent System Operator (ISO). In addition, SLDCs should be reinforced and ring fenced for ensuring functional autonomy.
Action: Govt. of India, State Govts.
Time Frame: 1 year
9.13.2 Training and certification of system operators need to be given focused attention. Sufficient financial incentives need to be given to certified system operators so that system operation gets recognized as specialized activity.
Action: Govt. of India, State Govts.
Time Frame: 3 months
9.14 Development of Intra-State transmission system
Intra-State transmission system needs to be planned and strengthened in a better way to avoid problems of frequent congestion.
Action: STUs
Time Frame: 2 years
9.15 Network visualization
9.15.1 Appropriate amendments should be carried out in Grid Connectivity Standards to restrain connectivity of a generating station or a transmission element without required communication and telemetry facilities.
Action: CEA,
Time Frame: 6 months
9.15.2 The Communication network should be strengthened by putting fibre optic communication system. Further, the Communication network should be maintained properly to ensure reliability of data at Load Despatch Cenres.
Action: CTU and STUs
Time Frame: One years
9.15.3 RTUs and communication equipments should have uninterrupted power supply with proper battery backup so that in case of total power failure, supervisory control and data acquisition channels do not fail.
Action: CTU and STUs
Time Frame: 3 months
9.15.4 In case of existing generating stations or transmission elements without telemetry facility, the same should be put in place at the earliest. If prolonged operation without telemetry continues, POSOCO should approach Central Commission.
Action: RPCs, POSOCO
Time Frame: 6 months
9.16 Reduction in Start-up time for Generators:
Large variations are observed in time taken for initiation of unit start up (Boiler light up) by the stations after availability of start-up power and also for start ups/light up of subsequent units. While subsequent start-ups were very fast (10-20 minutes) in some of the units, in other cases they took considerably longer time – several hours. Reasons for the delays in attempting first start-up and subsequent start-ups may be examined by the utilities in consultation with CEA. A standard procedure for preparatory activities and sequence of start up may be put in place by the stations to restore units as early as possible particularly in contingencies.
Action: CEA, Generating Utilities and RLDCs
Time Frame:one year
9.17 Review of Transmission Planning Criteria
At inter-State level, the entire landscape has changed over past few years. With de-licensing of generation and provision of open access in Electricity Act, 2003 and development of organized electricity markets, lot of generation is coming in the form of merchant generation. Four out of the five regions have been integrated and formation of National Grid is on the horizon. Under such scenario, there is need review the Transmission Planning criteria.
Action: CEA
Time Frame: 3 months
9.18 Strengthening of system study groups in various power sector organizations:
There is need to reinforce system study groups in power sector organisations to analyse the system behaviour under different network status/ tripping of lines/outage of generators. Where these do not exist, these should be created.
Action: CEA, CTU and STU
Time Span: one year
9.19 Formation of a task force to study the grid security issues:
It was felt that a separate task force may be formed, involving experts from academics, power utilities and system operators, to carry out a detailed analysis of the present grid conditions and anticipated scenarios which might lead to any such disturbances in future. The committee may identify medium and long term corrective measures as well as technological solutions to improve the health of the grid.
Action: MOP, CEA
Time Frame: 1 month
