it will aware with new trends in modern power system.

1. Submitted By :
Indubhushan Kumar
Assistant Professor -II
Department of Electrical Engineering
JECRC University , Jaipur
POWER SYSTEM SECURITY & SMART GRID

2. OVERVIEW
o POWER SYSTEM SECRUITY
o CONTINGENCYANALYSIS
o VOLTAGE STABILITY
o SMART GRID

3. What is power system security?
Power system security may be looked upon as the probability of the system’s
operating point remaining within acceptable ranges given the probabilities of
changes in the system (contingencies)and its environment.

4. Fig : Classification Of Power System Stability

5. Power system Security
 To determine whether, and to what extent, the system is reasonably safe from
serious interference to its operation.
 Major concern in planning, design and operation stages of electric power systems
 Important issue in planning and operation stages of a power system
 Violation of any security related inequality constraints pushes the system to
emergency or insecure state
 Power system security problems are classified as static and dynamic.
 Static security problem evaluates the system steady state performance for all
possible postulated contingencies.
 Dynamic analysis pertains to long term behavior of the system of the order of few
minutes under transient disturbances.

6. Major Components Of Security Assessment
System monitoring
Contingency analysis
Preventive and corrective actions

7. System Monitoring
 The prerequisite for security assessment of a power system is the knowledge of
the system states. Monitoring the system is therefore the 1st step.
 Measurement devices dispersed throughout the system help in getting a picture
of the current operating state. The measurements can be in the form of power
injections, power flows, voltage, current, status of circuit breakers, switches,
transformer taps, generator output etc., which are telemetered to the control
centre.
 Usually a state estimator is used in the control centre to process these
telemetered data and compute the best estimates of the system states.
 Remote control of the circuit breakers, disconnector switches, transformer taps
etc. is generally possible. The entire measurement and control system is
commonly known as supervisory control and data acquisition (SCADA)
system.

8. Contingency Analysis
 Once the current operating state is known, the next task is the
contingency analysis. Results of contingency analysis allow the
system to be operated defensively.
 Major components of contingency analysis are:
 Contingency definition
 Contingency selection
 Contingency evaluation

9. Contingency analysis...contd.
 Contingency definition involves preparing a list of probable contingencies.
 Contingency selection process consists of selecting the set of most probable
contingencies in preferred; they need to be evaluated in terms of potential
risk to the system.
 Usually, fast power flow solution techniques such as DC power flow are
used to quickly evaluate the risks associated with each contingency.
 Finally, the selected contingencies are ranked in order of their security, till
no violation of operating limits is observed.

10. Preventive And Corrective Actions
 Preventive and corrective actions are needed to maintain a secure operation of
a system or to bring it to a secure operating state.
 Corrective actions such as switching of VAR compensating devices, changing
transformer taps and phase shifters etc. Are mainly automatic in nature, and
involve short duration.
 Preventive actions such as generation rescheduling involve longer time scales.
Security-constrained optimal power flow is an example of rescheduling the
generations in the system in order to ensure a secure operation.

11. On-line security assessment
 In earlier days, security assessment in a power system was mainly offline
in nature. Predefined set of rules or monographs' were used to assist the
operators in the decision-making process.
 However, due to the highly interconnected nature of modern power
systems, and deregulated energy market scenarios, operating conditions
and even the topology of a power system changes frequently. O-line
techniques for security assessment are therefore no- longer reliable in
modern power systems.
 On-line security assessment techniques use near-real-time measurements
from different locations in a power system, and continuously update the
security assessment of the system.

12. Fig : On-line Power System Security Analysis

13. Tools for Contingency Analysis
 DC Power Flow
 Linear sensitivity factors
 Line outage distribution factor

14. Algorithm For Contingency Analysis

15. What is Voltage stability ???
 “It is the ability of the system to maintain steady state
voltages at all the system buses when subjected to a
disturbance”.
 If the disturbance is large then it is called as large-
disturbance voltage stability and if the disturbance is
small it is called as small-disturbance voltage stability”

16. Voltage stability Contd……
 Voltage stability of a system can be analysed either by static analysis or
dynamic analysis.
 In static analysis the system is assumed to be in steady state and hence
instead of taking the DAE of the system only algebraic equations are
considered. This type of analysis is suitable for small-disturbances in the
system.
 For large disturbances the DAE are solved and the system response over a
certain period of time is observed.
 It is important that for voltage stability the loads should be properly
modelled as each type of load will affect the system voltage stability in a
different way.

17. Effect of load type on voltage stability
Fig. : P-V curve with stable and unstable operating point

18. Fig. : P-V curve for different power factor load

19. Fig. : Q-V curve for different load real powers

20. Sensitivity Analysis
 One way of finding the voltage stability is to check the
sensitivity of each bus voltage with respect to the
reactive power injected at that bus .
 if the sensitivity is positive then it means the operating
point is stable and is on the right side of the locus of
the knee points in Fig. if it is negative then it is on the
left side.
 This stable region and unstable region are only
applicable to constant MVA loads.
 In case of constant impedance and constant current
loads the loads interact with the system and settle at a
new operating point as there is no requirement of
constant MVA.

21. Smart Grid Technology
 A smart grid system is a self-sufficient electricity
network system based on digital automation
technology for monitoring, control, and analysis
within the supply chain.
 This system can find the solution to the problems
very quickly in an existed system that can reduce
the workforce and it will targets sustainable,
reliable, safe and quality electricity to all
consumers

23. Benefits Associated With Smart Grid
 More efficient transmission of electricity
 Quicker restoration of electricity after power disturbances
 Reduced operations and management costs for utilities, and ultimately lower
power costs for consumers
 Reduced peak demand, which will also help lower electricity rates
 Increased integration of large-scale renewable energy systems
 Better integration of customer-owner power generation systems, including
renewable energy systems
 Improved security

24. Components Of Smart Grid
 Smart Power Meters
 Smart thermostats
 Smart Substations
 Super Conducting Cables
 Integrated communications (PLC & SCADA)
 Phasor Measurement Units (PMU)

25. Applications of Smart Grid
Future Applications and Services Real Time Market
Business and customer care
Application data flow to/ from end-user energy
management systems
Smart charging of PHEVs and V2G Application data flow for PHEVs
Distributed generation and storage Monitoring of distributed assets
Grid optimization
Self-healing grid: fault protection, outage
management, dynamic control of voltage, weather
data integration, centralized capacitor bank control,
distribution and substation automation, advanced
sensing, automated feeder reconfiguration.
Demand response
Advanced demand maintenance and demand
response, load forecasting, and shifting.
AMI (Advanced metering infrastructure)
Provides remote meter reading, theft detection,
customer prepay, mobile workforce management

26. THANK YOU
GO GREEN