Fifteenth National Power Systems Conference (NPSC), IIT Bombay, December 2008
Wide-Area Protection and Control: Present
Status and Key Challenges
Seethalekshmi K., S.N. Singh, Senior Member, IEEE and S.C. Srivastava, Senior Member, IEEE
system, are early recognition of large and small scale
instabilities, increased power system availability through well
coordinated control actions, operation closer to the limit
through flexible relaying schemes, fewer load shedding events
and minimization of the amount of load shedding.
The main disadvantage of the present conventional method
of system monitoring is the inappropriate system dynamic
view, or the uncoordinated local actions, like that in
decentralized protection devices. Solution to the above can be
achieved through dynamic measurement system using
synchronized phasor measurement units. A system comprising
of synchronized phasor measurements and performing the
tasks of stability assessment with adaptive relaying is called a
Wide-Area Monitoring and Control (WAMC) system [1].
This paper provides a comprehensive survey of power
system applications related to protection and control based on
wide area measurements. The paper is organized as follows:
section II describes the requirements for a wide-area
protection system. In Section III architecture of wide-area
protection system is discussed. Section IV critically reviews
the research work carried out in the field of wide area based
adaptive protection and categorizes the application fields. In
section V, control schemes for small signal stability analysis
based on wide area measurements are reviewed and are
classified based on controller structures. Section VI lists a few
key issues and research challenges in the wide area based
protection and control schemes. Finally section VII presents
the main conclusions.
Abstract— The electricity supply industries need tools for
dealing with system-wide disturbances that often cause
widespread blackouts in power system networks. When a major
disturbance occurs, protection and control measures assume the
greatest role to prevent further degradation of the system,
restore the system to a normal state, and minimize the impact of
the disturbance. Continuous technological development in
communication and measurement have promoted the utilization
of Phasor Measurement Unit (PMU) based Wide-Area
Measurement Systems (WAMS) in power system protection and
control for better management of the system security through
advanced control and protection strategies. In this paper, a
comprehensive survey is made on recent developments in this
field. Focus of the survey is on WAMS based adaptive relaying
and control applications and highlights key issues and challenges.
I. INTRODUCTION
M
ODERN power systems are in the process of continuous
development which has lead to complex interconnected
networks. Financial pressure on the electricity market and on
grid operators forces them to maximize the utilization of highvoltage equipment, which very often lead their operation
closer to the limits of the system. This approach of ensuring
economic operation is possible provided the system is
equipped with a well designed and coordinated protection and
control strategy to deal with wide spread disturbances in the
system.
Traditional power system protection and control measures
are based on local measurements. However, it is quite
difficult to maintain the stability and security of the system on
the whole, if only local measurements are employed in the
protection and control schemes. One promising way is to
provide a system wide protection and control, complementary
to the conventional local protection strategies. While it is not
possible to predict or prevent all contingencies that may lead
to power system collapse, a wide-area monitoring and control
system that provides a reliable security prediction and
optimized coordinated action is able to mitigate or prevent
large area disturbances. The main tasks, which can be
accomplished through wide-area based monitoring and control
II. REQUIREMENTS FOR A WIDE AREA PROTECTION SYSTEM
Wide-area protection system is employed to fulfill the
two main objectives of increasing transmission capability as
well as system reliability. Closer analysis on the above two
broad objectives require the focus on the following [1]:
x Coordination with existing local protection system with
a view to enhance the system reliability and security by
appending the protection system with system wide
information
x Identification of critical situations and determining
appropriate remedial actions with regard to the following
physical phenomena:
a.
Transient (angle) instability (first swing)
b. Small signal angle instability mainly due to poor
damping
c.
Frequency instability
Seethalekshmi K. (e-mail: [email protected]) and S.N. Singh (email:
[email protected]) are with the Department of Electrical Engineering, Indian
Institute of Technology Kanpur, Kanpur – 208016, India. (Tel. 91-51225977874, 2597009). S. C. Srivastava (e-mail: [email protected]) is a
Visiting Faculty in the Department of Electrical and Computer Engineering at
Mississippi State University, Box 9571, MS 39762, USA (Tel. +662-3252295), on leave from Indian Institute of Technology Kanpur, India.
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Fifteenth National Power Systems Conference (NPSC), IIT Bombay, December 2008
d. Short-term voltage instability
e.
Long-term voltage instability
These phenomena are now-a-days partly covered by pure
local actions as part of the classical protection schemes or
manually utilizing the Supervisory Control and data
Acquisition (SCADA)/Energy Management System (EMS)
view.
The major drawbacks of these conventional solutions are that
local protection devices do not consider a system wide view
and are, therefore, not able to take optimized and coordinated
actions. The SCADA/EMS system instead is not able to
directly catch the dynamics of the system and is, therefore,
focused on the steady state operational requirements.
These drawbacks define the following major requirements for
wide-area protection systems.
x Dynamic measurement and representation of events
x Wide area system view
x Coordinated and optimized stabilizing actions
x Adaptive relaying in coordination with local
protective devices
x Handling of cascaded outages
Benefits of using wide area measurement, protection and
control schemes have been discussed in [2], which has
classified the major application areas in eleven categories
dealing with the important steady state and transient issues in
the power system. Reference [2] also reviewed the phasor
technology and identified the implementation gap, at present,
with respect to each of the identified power system issues.
Powerful, sensitive, and robust, wide-area protection
systems can be designed based on decentralized
interconnected system protection terminals. These terminals
are installed in substations, where actions are to be made or
measurements are to be taken. Actions are preferably local to
increase system security. Relevant power system variable data
are transferred through the communication system that ties the
terminals together. Different system protection schemes can
be implemented in the same hardware.
C. Multilayered Architecture
While the above two designs attempt on extending the
“reach” of existing control domains (protection terminal being
one domain and EMS being the other), there is no guarantee
that the end solution will be comprehensive. A comprehensive
solution is one that integrates the two control domains,
protection devices and EMS. Such a solution is depicted in
Fig.1 [3].
System
Protection
Center
GPS
PMU
G
G
PMU
PMU
PMU
Local Protection Centers
III. ARCHITECTURE OF WIDE-AREA PROTECTION SYSTEM
Fig. 1. Multilayered wide-area protection architecture [3]
The requirements of a wide-area protection system and the
current technological levels vary among different power
utilities. Hence, the architecture for the protection system may
also be different. Three major design architectures, normally
adopted are discussed as follows [3]-[5]:
There are up to three layers in this architecture. The bottom
layer is made up of PMUs. The next layer up consists of
several Local Protection Centers (LPCs), each of which
interfaces directly with a number of PMUs. The top layer, the
System Protection Center (SPC), acts as the coordinator for
the LPCs. This kind of wide area protection systems will most
likely be common in the future.
To design a three layered architecture for a wide-area
protection system, the first step generally aims at achieving
wide-area monitoring capability. For this WAMS, PMUs are
widely employed. In WAMS applications, many PMUs are
connected to a personal computer called data concentrator, so
that the dynamic behaviour of a power system could be
obtained from the concentrator. However, the quantities to be
measured by PMUs and the locations for installations of PMU
are dependent on many factors. Several publications had
appeared in solving Optimal PMU Placement (OPP), i.e., a
scheme with minimum PMUs meeting the requirement of the
system observability in a monitoring system [7]-[15].
A reliable and fast communication system is an
indispensable element for effective wide-area protection
system. The important factors, which are considered in
building a robust and reliable communication network, are
media, communication protocols and topology of the network.
Currently a combination of power line carrier, radio,
microwave, leased phone lines, satellite systems, and optical
fiber is being utilized in protection systems [3]. These
A. Enhancements to SCADA/EMS
At one end of the spectrum, enhancements to the existing
EMS/SCADA can be made. These enhancements are aimed at
two key areas: information availability and information
interpretation. Information availability may be enhanced by
providing system dynamic information through PMUs [6]
from all over the grid. Based on these measurements,
improved state estimation can be performed which result in
improved accuracy of power system states prediction. Since
the possibilities of new functions in the SCADA/EMS system
tend to be limited, it is better to provide them as “stand alone”
solutions.
B. “Flat Architecture” with System Protection Terminals
Protection devices or terminals are traditionally used in
protecting equipments (lines, transformers, etc.). Modern
protective devices have sufficient computing and
communications capabilities that they are capable of
performing beyond the traditional functions. When connected
together via communications links, these devices can process
intelligent algorithms (or “agents”) based on data collected
locally or shared with other devices.
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Fifteenth National Power Systems Conference (NPSC), IIT Bombay, December 2008
systems are also associated with communications delay or
latency. It is defined as the time required for transmitting data
from the measurement location to a control center or data
concentrator, and the time required ultimately to communicate
these data to control devices.
Delays in communication are mainly due to the following
factors [16]:
x Transducer delays
x Window size of Discrete Fourier Transform (DFT)
x Processing time
x Data size of PMU output
x Multiplexing and transitions
x Communication links involved
x Data concentrators
It is imperative for the utility to choose a right
communication link depending upon the control action to be
performed.
A. Wide Area Measurement System Based Fault Location
Fault location may be based upon phasor measurements or
on traveling wave concepts. If phasor measurements are used,
it is possible to make the best possible estimates of fault
location from each end, and then average the two results to
obtain the double-ended fault location result [19]. In [21-23] a
protection scheme is suggested for fault detection, direction
discrimination, classification and location based on
synchronized phasor measurements. Fault detection index, in
terms of Clarke’s components of the synchronized voltage and
current phasors, is derived. The fault detection index is
composed of two complex phasors and the angle difference
between the two phasors determines whether the fault is
internal or external to the protected zone. On line parameter
estimation is carried out for ensuring the performance of the
protection scheme. Proposed protection scheme is shown in
Fig 2. [23]
Bus A
GPS
Bus B
IV. ADAPTIVE RELAYING BASED ON WIDE AREA
MEASUREMENT SYSTEM
It has been recognized that many relay settings are often
compromise settings, which are reasonable for many
alternative conditions that may exist on a power system,
which may not be the best setting for any one condition. Thus,
many relay settings are compromises in terms of sensitivity or
speed of response to faults, in order that they are adequate for
all possible faults. A definition of adaptive relaying, which
embodies this idea, is as follows [17], “Adaptive protection is
a protection philosophy which permits and seeks to make
adjustments in various protection functions automatically in
order to make them more attuned to prevailing power system
conditions.” The need of adaptive relaying and concepts of
adaptive relaying are clearly depicted in [18], where on line
settings for conventional relays are worked out under system
configuration changes. Adaptive relaying may include
schemes for various protection functions, such as fault
location, fault classification and adaptive adjustments of relay
settings.
Application of microprocessor based phasor measurements
to adaptive protection was investigated in [19]-[20] and
Reference [20] brought out a scheme for working out adaptive
settings for out-of-step blocking and tripping.
IEEE Working group has recommended the usage of
coordinated wide-area adaptive protection for reducing the
power system disturbances. Research in this area suggests that
the wide area adaptive protection should progress in two
forms, which are anticipatory and responsive [5]. In
anticipatory schemes, protection system characteristics are
altered at the time of system stress. In responsive schemes,
protection system reacts to an emergency state by taking
additional switching actions to restrict the impact of a
protective devices’ maloperation.
Hence wide–area protection can be coordinated with the
conventional protection through the following:
x Fault location based on wide-area measurement system
x Adaptive relay settings based on wide-area information
x Adaptive back-up protection schemes utilizing wide
area measurements
Communication
Links
PMU A
To C.B.
PMU B
To C.B.
R/T
R/T
Relay
Relay
Fig. 2: Block diagram of a wide area protection scheme [23]
Applying series compensation in power systems can
increase power transfer capability, improve transient stability
and damp power oscillations. However, since the variation of
series compensation voltage remains uncertain during the fault
period, the protection of power systems with series
compensated lines is considered as one of the most difficult
tasks and is an important subject of investigation for relay
manufacturers and utility engineers. Effect of series
compensation on line protection is well analyzed in [24-26].
Solution, in the case of lines, protected with fixed and
controllable series capacitors in combination with Metal
Oxide Varistor (MOV), is suggested in [27]. Wide-area
measurement system based fault location scheme is worked
out in [28] in a system comprising of a series Flexible
Alternating Current Transmission System (FACTS) controller.
Traditional approach in computing voltage drop across the
series compensation device is by using the device model.
Algorithm proposed in [28] utilizes only synchronous
measurement data at both ends of the transmission line, to
estimate fault location of a line employed with Thyristor
Controlled Series Compensator (TCSC).
B. Wide Area Back-up Protection Schemes
As wide-area measurements are adopted, long-time delay is
no longer necessary to ensure the coordinated selection
between primary protections and backup ones, while it is
necessary in the conventional protections. As a result, the
delay for isolating faults by backup protection could
significantly be reduced. Wide-area differential backup
protection schemes are described in [29]-[30]. A strategy to
prevent cascaded outages is presented in [31-32] through a
wide area Backup Protection Expert System (BPES). The role
of substation based wide-area backup protection system is to
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Fifteenth National Power Systems Conference (NPSC), IIT Bombay, December 2008
monitor the existing conventional protection relays and to
provide appropriate backup protection to all lines, busbars
and circuit breakers in an intelligent way, with minimized
impact on the network. With its global view of the protected
network, the wide-area based backup protection device is
capable of locating a fault precisely to trip only the circuit
breakers necessary to isolate a fault.
V. ADAPTIVE CONTROL BASED ON WIDE AREA
MEASUREMENT SYSTEM
Fig. 4. Framework of multi-agent controllers [35]
Damping of power system oscillations between
interconnected areas is very important for secure operation of
the system. The oscillation of one or more generators in an
area with respect to the rest of the system are called local
modes, while those associated with groups of generators in
different areas oscillating against each other are called interarea modes [33]. Local modes are largely determined and
influenced by local area states and the control measures for
the same are relatively simple, and a conventional Power
System Stabilizer (PSS) may be sufficient to solve the
problem. However, control measures for the inter-area modes
are rather complicated and, therefore, extensive concerns arise
in this area. The effectiveness in damping inter-area modes is
limited because inter-area modes are not as highly controllable
and observable in the generator’s local signals as local modes.
However, local controllers are tuned in a non-optimum
fashion to damp both inter-area and local plant modes. Hence,
an alternative technique to provide effective damping of the
inter-area modes is desirable. Analysis of the inter-area
phenomenon has shown that certain signals measured at
electrical centers of the group of generators separated from the
rest of the system provide more effective control. These
signals could be measured by the wide-area measurement
system and then transmitted to an optimally located PSS/
FACTS controller to damp out the oscillation [34].
Application of wide-area measurements for control of interarea modes broadly fall in the three categories of controller
design as mentioned below:
x De-centralized controllers
x Centralized Controllers
x Multi-agent Controllers
Figs. 3 and 4 shows the general architecture of the above
types of control structures [35], which are discussed in
following subsections.
A. De-Centralized Controllers
Decentralized design of controller design consists of
providing an additional global signal to the existing local
controllers with a view to provide enhanced damping to interarea modes.
A two-level PSS design strategy is described in [36], where
the first level of control is derived from local signals and is
designed to deal with the local modes. The second level of
control is supplied from a coordinator using selected global
states to deal with the poorly damped inter-area modes. The
global signals have also been employed in SVCs for
enhancement of damping the inter-area modes. Local and
inter-area modes are identified through the eigen value
analysis. Location of the PSSs is determined using
participation factors or transfer function residues [37]. In this
work, interaction between sub-systems (i.e. generators) is
neglected and also the time delay in obtaining the global
signal is not considered. A group headed by I. Kamwa has
carried out a series of research work on wide-area control for
inter-area modes [38]-[41].
The state space system identification technique is first
applied to build a large-scale small-signal model in the HydroQuebec’s system, and then used to design global stabilizing
controllers [38]. Once the state space model was obtained,
observability and controllability measures were computed and
subsequently five control sites were paired with remote PMUs
spread over nine electrically coherent areas. These PSSs have
two control loops, a speed sensitive local loop operating in the
usual way, and a WAMS-based global loop using a single
differential frequency signal between two suitably selected
areas. The tuning and coordination technique for the complex
multiple controllers and their impacts on power system
operation are also discussed in the paper. Extensive studies for
this control system were carried out in [39], and specifically
the decentralized/hierarchical architecture, system modeling,
tuning and coordination technique, and simulation and
assessment of impacts on the system are described in more
detail. Sequential tuning method has been employed for
tuning the PSSs. However, the processing and communication
delay was not discussed.
A detailed analysis of the control loop selection is presented
in [40], and a straightforward and easy-to-implement
methodology for loop selection has been proposed. Two
complementary measures are employed in the measurement
and control-signal selection. One is the geometric measure for
maximizing the controllability and observability of inter-area
Fig. 3. Framework of centralized and decentralized controllers [35]
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Fifteenth National Power Systems Conference (NPSC), IIT Bombay, December 2008
The stabilizing signals are obtained from remote locations
based on the observability of the critical modes.
A
modes, the other is the singular-value based total interaction
measure for minimizing the interactions between the local or
global loops at the inter-area natural frequency. An
assessment on wide-area damping control over local control is
presented in [41] through numerical simulations of a threearea test system and a revised Hydro-Quebec network. The
results suggest that the wide-area damping control has obvious
technological advantages [42].
+ f damping control design based on the mixed-sensitivity
formulation in a LMI framework is carried out. In [48], the
work reported in [47] is extended to model the signal
transmission delay. A predictor based + f controller is
proposed to take care of time delayed systems. A unified
Smith predictor approach is used in this work to formulate the
damping controller design problem for a power system having
a signal transmission delay of 0.75s. Difficulty in + f based
control approach is in the selection of the weighting matrices
B. Centralized Controllers
Centralized design of controllers use a large amount of
information from the system to be controlled for providing
conservative and more efficient solutions compared to
conventional approach. In [43], a remote feedback centralized
controller is proposed. The application of Linear Matrix
Inequalities (LMI), to the tuning and optimization of the
controller, makes it be able to deal with the time delay in its
input signals. A two-loop framework, of a wide-area stability
control system, has been proposed in [44] , wherein the inner
loop generates real-time damping control actions using widearea feedback signals, while the external loop adjusts the
controllers’ parameters in a near-real time to accommodate the
variation in the operating conditions. In this work, a modal
reduction method based on the disturbance injection technique
and an improved prony algorithm is suggested.
Comprehensive controllability and observability indices are
used to properly locate the observers (PMUs) and controllers.
Controller parameters are obtained through the solution of an
information-structured-constrained
Linear
Quadratic
Regulator (LQR) problem. Signal transmission delay has
been modeled using a least-squares based polynomial
prediction algorithm. Test results of the proposed wide-area
control system show the advantages of the scheme over
traditional local PSSs.
In [45], a two level hierarchical structure is proposed to
improve the stability of multi-machine power systems. It
consists of a local controller for each generator at the first
level helped by a multivariable central one at the secondary
level. The secondary level controller uses remote signals from
all generators to synthesize a decoupling control signal that
improves the local controllers’ performances. In this work,
problems of voltage regulation and rotor oscillations damping
are addressed simultaneously. The proposed secondary level
controller continuously adapts its parameters through a gain
scheduling algorithm. An extension to the above work is
reported in [46] in which Smith prediction approach is used to
preserve the controller performance in presence of remote
measurements delays and communication delays between the
central and the local controllers. It has been reported that the
local controllers’ performances are considerably increased by
the secondary control action and system stability is improved
in presence of severe contingencies.
A Multiple input single output controller is designed in [47]
for a TCSC to improve the damping of the critical inter-area
modes. The proposed work employs local as well as remote
stabilizing signals for damping out the inter area oscillations.
C. Multi-agent Controllers
A Supervisory level PSS (SPSS) is proposed in [49] using
wide-area measurements. The coordination of the robust SPSS
and local PSS is implemented based on the principles of
multi-agent system theory. LMI based + f controllers using
selected wide-area measurements are embedded into the SPSS
control loop to accommodate power system non-linear
dynamic performance and model uncertainties.
The
supervisory PSS operates as a software agent and is composed
of three main components that are agent communications,
fuzzy logic controller switch and robust control loops. Fuzzy
logic controller switch selects the appropriate robust controller
for the corresponding system operating condition. The control
signals are sent to local machines to damp system oscillations
through the machines’ excitation systems. In this work, the
control loops are designed off line, which may cause problems
when the operating conditions are varied to a larger extent.
Also, signal transmission delays are not considered in this
work. However, the test results of the proposed algorithm
show promising results over conventional PSS approach for
damping inter-area oscillations.
In recent years, various defense plans have been framed for
utility to protect the grid against various power system threats
[50]. The power system frequency and voltage monitoring
tasks in Hydro– Quebec is performed using programmable
load shedding scheme, which offers customized solution to
the power system protection [51]. Electricite de France (EDF)
had introduced French defense plan for predicting transient
instabilities in the system through the phasor measurements.
This coordinated defense plan strategy utilizes a decision
making centre called ‘central point’, which has a global view
of the power system operation with real time knowledge of the
phase angles over all the areas [52]. The Tokyo Electric
Power Company (TEPCO) has been operating the islanding
protection scheme based on the phasor angle difference
obtained from the phasor measurements since 1984 [53].
VI. KEY ISSUES AND CHALLENGES
Several control algorithms, which are listed in the previous
sections, have been applied in power system as an additional
protection measure. However, the practical applications of
WAMS, integrated with the conventional protection, are only
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Fifteenth National Power Systems Conference (NPSC), IIT Bombay, December 2008
reported in the area of WAMS based fault location. Some of
the key issues and challenges in the wide area protection and
control are as follows:
x A lot of WAMS based designs are available to protect
system’s security. However, a comprehensive defense
plan, which could handle all possible kinds of instabilities,
is yet to be developed. Hence, OPP, which is presently
viewed on the basis of special protection/ control function
considered, is required to be tackled as a problem which
provides complete topological observability as well as
numerical observability of the system.
x Selection of proper architecture of wide-area protection
system is important in terms of system reliability and speed
of information exchange between system components.
Three possible architectures are discussed in section III of
this paper for wide area protection system. However, a
combination of these architectures may be preferred in the
case of comprehensive defense plan. This is because,
comprehensive plan intends to find solutions for system
security problems, which are local (e.g. adaptive relaying
for primary protection, long term voltage instability) or
global (frequency instability, angular instability, control
coordination for small signal stability) in nature.
x Dynamics of loads are not being considered in frequency
instability protection measures based on WAMS, to the
best of authors’ knowledge. For a realistic solution for
frequency instability, it is inevitable to consider the same
though considerable challenge is involved in obtaining
dynamic loading characteristics.
x Events of cascaded tripping are reported due to the
operation of overreaching zones of distance relay under
stressed situation of power system. It may be a challenging
task to employ WAMS based anticipatory adaptive
relaying schemes to tackle the situation.
x Flexible protection scheme will be a potential solution for
dealing with uncertainties involved in distance protection
of transmission lines containing series FACTS devices.
This scheme demands the knowledge of control parameters
of FACTS devices for zone classification in distance
relays. WAMS can be employed to obtain the control
parameters of FACTS devices in a very short time span.
x The wide area measurement based protection and control
strategy should be designed to account for time delayed
information exchange from PMUs to Phasor Data
Concentrator (PDC) and from PDCs to control centers.
Fixed delays and polynomial prediction algorithm for
delays are already incorporated in the adaptive control
schemes. However, the real time adaptive identification
techniques of (varying) delays need to be developed.
presently employed local protective measures along with
SCADA/EMS system and identifies the bottlenecks in the
system. Requirements of a wide-area protection system have
been identified in order to overcome these shortcomings.
Three possible architectures are discussed for wide area
protection scheme either as an extension to the present
SCADA/EMS system or as a dedicated multilayered structure.
This paper brings out a categorical classification of relaying
and control schemes reported in the literature. One of the
major issues in the application of this relatively new
technology is integration of WAMS based adaptive relaying
schemes with conventional protection schemes comprising of
fault detection, fault identification and fault location. Control
algorithms incorporating wide area based control schemes are
already available for various system stability problems like
small signal stability, voltage instability, angular instability
etc. Further improvements on the same could be in the
methods of dealing with signal transmission delays in an
adaptive manner.
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BIOGRAPHIES
Seethalekshmi K. obtained her B.Tech from Regional Engineering College,
Calicut, Kerala, India and M. Tech. from College of Engineering, Trivandrum,
Kerala, India and is presently pursuing her Ph.D. in the Department of
Electrical Engineering, Indian Institute of Technology Kanpur, India.
S.N. Singh received M.Tech and Ph.D. from Indian Institute of Technology
Kanpur, India. Presently, he is Professor in the Department of Electrical
Engineering, Indian Institute of Technology Kanpur. He is a Fellow of IETE
(India) and senior member of IEEE.
S. C. Srivastava received his PhD in Electrical Engineering from Indian
Institute of Technology, New Delhi, India. He is presently a Visiting Professor
in the ECE Department at Mississippi State University, USA on leave from
Indian Institute of Technology, Kanpur, India. He is a Fellow of INAE (India),
IE (India) & IETE (India), and senior member of IEEE.
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