Charusat University CE 2.1: Synchrophasor-Based Load Shedding Project

This project details a synchrophasor-assisted frequency and voltage stability-based load shedding scheme designed for power systems. The project utilizes Wide Area Monitoring and Control Systems (WAMCS) and Phasor Measurement Units (PMUs) to gather real-time system data, enhancing the stability of the power grid. The project objectives include understanding synchrophasors, stabilizing the power system, and ensuring voltage and frequency stability. The student's responsibilities included designing the load shedding scheme, handling equipment, and writing project reports. The project explores conventional protection schemes and introduces the advantages of synchronized measurement technology for real-time control. The project also discusses different architectures like enhancement to SCADA/EMS functions, flat architecture, and multilayered architecture. Issues such as state estimation and proper representation of existing protective devices are addressed, along with solutions like simulation and fast computation of system dynamics. The project provides an overview of power system stability and its importance.

CE 2.1 Project Information
Name of the project: A Synchrophasor Assisted Frequency and Voltage Stability
Based Load Shedding Scheme for Power
Location of the project: Charotar University of Science and Technology
(CHARUSAT), Gujarat, India
Project Duration: Please Fill
Organization: Charotar University of Science and Technology
Role and Designation during the time: Student of Electrical Engineering
CE 2.2 Project Background
CE 2.2.1 Characteristics of the project
This particular project is the important amalgamation of frequency as well as voltage
stability based load shedding scheme. The control and protection solutions, by utilizing
synchrophasor based wide area monitoring and control system or WAMCS, are being
proposed for avoiding voltage, frequency, and the instabilities of rotor angle. WAMCS helps
in gathering the information of the system from several locations and then finally sends wide
area control signals in answer to the disturbances of system. The system data is evelauated by
the phasor measurement units or PMUs and are then sent to a particular phasor data
concentrator or PDC. PDCs, in returning send the entire system data to a particular central
location. This WAMCS usually forms a significant component for the implementation of
smart grid, since it helps to facilitate the monitoring of system wide, control and assessment
of functions.

CE 2.2.2 Objectives developed for the project
This project study comprises of various objectives. They are given below:
 To understand the concept and functions of a synchrophasor
 To stabilize power system by frequency and voltage stability load shedding scheme
 To ensure voltage and frequency stability
CE 2.2.3 Project Group
Figure 1: People involved in the project
CE 2.2.4 My responsibilities throughout the project
I had taken the designing responsibilities of the synchrophasor assisted frequency and
voltage based load shedding scheme in any power system. I had utilized the guidelines of the
project for conducting work with knowledge as well as experience. After that, the design of
load shedding scheme was gained from forming the document of the project. I had even done
several works like cutting of the good damages and equipments foundation. It is needed for
complying with project rules and operations of equipments. I had also handled the tools, that

are needed for the purpose of handling as well as installation. I had also tested the equipments
for the purpose of commissioning. My next main responsibility was to write down the reports
of the project and document the crucial data in the report. Finally, being the team member of
this project I had properly involved into the estimation of budgets and timescales.
CE 2.3 Distinctive Activity
CE 2.3.1 Comprehending the Theory of the project
Conventional protection scheme have been implemented through local protection
devices. These conventional local devices are non- adaptive and are not capable of taking
optimized and co-ordinate action to deal with the impact of wide spread system disturbances.
For the secure operation of power system relaying scheme should be adaptive to various
system operating condition. Under emergency conditions, the effective controls can be
derived with the availability of the real-time system dynamic states. The present Supervisory
Control and Data Acquisition/Energy Management System or SCADA/EMS) is unable to
derive the dynamic information of the system at a rate required for the real-time control
actions. Recent development of Synchronized Measurement Technology or SMT offers a
paradigm shift in the field of power system measurements. This technology has approached
to the development of a new class of Wide Area Monitoring, Protection, and Control or
WAMPAC systems for reliable operation of the power systems. WAMPAC functions
encompass the system wide monitoring, coordinated real time protection and control
functions to counter the propagation of any major disturbances in the power system.
An AC waveform can be mathematically represented by the equation:
x(t) = Xm cos (wt + Φ ) (1.1)
where,

Xm = magnitude of the sinusoidal waveform
w = 2*π*f where f is the instantaneous frequency
Φ = angular starting point for the waveform
CE 2.3.2 Engineering Knowledge and Skills applied in the project
I have abilities of critical thinking and as the understudy of electrical engineering, I
am expected to think and perform sensibly. Those abilities perfectly help me to ensure that
the project work runs efficiently. I also have information impacting the instruments of
electrical by simply testing of all the electrical parts and equipments. I have also applied my
computer proficiencies in this particular project for the purpose of documentation. These
computer proficiencies were extremely important for the project and should had been applied
in perfect scenario.
CE 2.3.3 Accomplishment and task performed
This was my first minor project in engineering career. Therefore, I paid extra attention
to the project outcome. The project became successful due to the wide area protection and
control architectures. The architecture of the wide area protection system depends upon the
protection and control function to be performed. The three major designs used in this project
are as follows:
i) Enhancement to SCADA/EMS functions: Information availability and
interpretation can be enhanced at the existing SCADA system by providing system dynamic
information through the PMUs deployed in the grid. Based on these measurements, state
estimation is improved.
ii) Flat Architecture with system protection terminals: Modern protective devices have
sufficient computing and communication capabilities. When they connected together via

communication links, these device can process intelligent algorithms based on the data
collected locally or shared with the other device. Powerful wide area protection systems can
be designed based on the decentralized interconnected system protection terminals installed
at substation, where actions are to be taken.
iii) Multilayered architecture: The architecture discussed in (i) and (ii) , attempt to
extend the capability of an existing EMS and protection terminal. However, a versatile
architecture is required to integrate the local data at system protection terminals with the
information at the centralized location.
Figure 2: Multilayer Architecture
It is a three layered structure, where the base level requirement is the availability of
the PMUs. The next layer consists of local protection centres that interact with PMUs. The
top layer includes a system protection centre (SPC) and the function of the SPC, also referred
sometimes as super PDC is to act as a coordinator among the LPCs.
Synchrophasor data can be used to enhance grid reliability for both real-time
operations and offline planning applications as listed below:
The Real-time operations applications are as follows:
i) Wide-area situational awareness

ii) Frequency stability monitoring and trending
iii) Power oscillation monitoring
iv) Voltage monitoring and trending
v) Alarming and setting system operating limits, event detection and avoidance
vi) Resource integration
vii) State estimation
viii) Dynamic line ratings and congestion management
ix) Operations planning
x) Outrage restoration
The first step in the transient stability analysis is to solve the initial load flow and to
determine the initial bus voltage magnitudes and phase angles. The machine prior to
disturbance are calculated from a specific formula.
Figure 3: Power System Representation
Nodes n+1, n+2, .....n+m are the internal machine buses, i.e. the buses behind the
transient reactances. The node voltage equation with node 0 as reference for this network, as
shown below:

The diagonal elements of the bus admittance matrix are the sum of admittance
connected to it, and off diagonal elements are equal to the negative of the admittance between
nodes. The difference is that additional nodes are added to include the machine voltages
behind transient reactances. In addition, the diagonal elements are modified to include the
load admittances. To simplify the analysis, all nodes other than the generator internal nodes
are eliminated using the Kron reduction formula. The vector Im denotes the generator
currents and the vectors E’m and Vn represent the generator and load voltages respectively.
CE 2.3.4 Identified issues and their solutions
2.3.4.1 Issues
The problems or issues that were faced in this project mainly include reliable and
accurate state estimation or SE under stressed conditions, proper representation of existing
protective devices and schemes. The other issues were proper implementation of utility
practices and regulations, proper processing of the information and simulation of decision
making for each network structure, i.e. RTO, ISO, and many more and modularity and
adaptability to any potential scenario.
2.3.4.2 Solutions
For solving these issues, I felt that there was the requirement of simulation, proper
modelling and fast computation of the dynamics of the system. Wide area control addresses
automatic healing capabilities to some extent by proposing smart topology changes and

control actions. Dynamic islanding and fast load shedding are schemes available to maintain
as much as possible a healthy transmission system.
CE 2.4 Project Review
CE 2.4.1 Project overview
This project of Synchrophasor Assisted Frequency and Voltage Stability Based Load
Shedding Scheme for Power was my first minor project in engineering career. Power system
stability may be broadly defined as that property of a power system that enables it to remain
in a state of operating equilibrium under normal operating conditions and to regain an
acceptable state of equilibrium after being subjected to a disturbance. Depending on the
network topology, system operating condition and the form of disturbance, different sets of
opposing forces may experience sustained imbalance leading to different forms of instability.