Protective relaying

Engr. Mark Anthony Enoy
IIEE ZN CHAPTER


 To be able to know and be familiarize with the
different types of protective relays according to
where they are used in the actual power system.
 To be able to know the different functions of each
type of protective relay
Objectives


Definition:
- The IEEE defines protective relays as:
“relays whose function is to detect
defective lines or apparatus or other
power system conditions of an abnormal
or dangerous nature and to initiate
appropriate control circuit action ”
Introduction


Protective Relays detect and locate faults
by measuring electrical quantities in the
power system which are different during
normal and intolerable conditions. It
initiates the operation of the circuit
breaker to isolate the defective element
from the rest of the system.


I. To protect individuals
II. To protect equipment.
IMPORTANT ROLE OF
PROTECTIVE RELAYS


In the second case, their task is to
minimize the damage and expense
caused by insulation breakdowns which
(above overloads) are called ‘ faults ’ by
relay engineers.


These faults could occur as a result
from insulation deterioration or
unforeseen events, for example,
lighting strikes or trips due to
contact with trees and foliage (cluster
of plant leaves).


Relays are not required to operate
during normal operation, but must
immediately activate to handle
intolerable system conditions.


This immediate availability criterion (A
basis for comparison; a reference point against which other
things can be evaluated ) is necessary to avoid
serious outages and damages to parts of
or the entire power network.


Theoretically speaking, a relay
system should be capable of
responding to an infinite number of
abnormalities that may happen
within the network. However, in
practice, some compromises must be
made by comparing risks.


It is quite difficult to ensure stability and
security of the entire power system if only local
measurements are employed in monitoring,
protection and control schemes. One promising
way is to develop system wide protection and
control mechanisms, complementary to the
conventional local and zonal protection
strategies.


In order to implement such mechanisms, synchronized
phasor measurement may serve as an effective data
source from which critical information about the
system’s condition can be extracted.


Synchronized phasor measurement capabilities
are now one of the features available in the most
advanced protective relays commercially
available, and the use of this feature is proliferating.


A. Selectivity
B. Speed
C. Sensitivity
D. Reliability
E. Simplicity
F. economy
Fundamental Requirements
of Protective Relaying


It is the ability of the protective
system to select correctly that part
of the system in trouble and
disconnect the faulty part without
disturbing the rest of the system.
A. Selectivity


The relay system should
disconnect the faulty section as
fast as possible for the following
reasons:
1. Electrical apparatus may be
damaged if they are made to carry
the fault currents for a long time.
B. Speed


1. A failure on the system leads to a great
reduction in the system voltage. If the
faulty section is not disconnected quickly,
then the low voltage created by the fault
may shutdown consumers motors and
generators on the system may become
unstable.
2. The high speed relay system decreases the
possibility of development of one type of
fault into the other more severe type.


 It is the ability of the relay system to operate with
value of actuating quantity
 Sensitivity of a relay is a function of the volt-amperes
input to the coil of the relay necessary to cause its
operation.
 The smaller the volt-ampere input required to cause
the relay operation, the more sensitive is the relay
C. Sensitivity


 It is the ability of the relay system to operate under
the pre-determined conditions. Without reliability,
the protection would be rendered largely ineffective
and could even become a liability (An obligation to
pay money to another party).
D. Reliability


 The relaying system should be simple so that it can
be easily maintained. Reliability is closely related to
simplicity. The simpler the protection scheme, the
greater will be its reliability.
E. Simplicity


 The most important factor in the choice of a
particular protection scheme is the economic aspect.
Sometimes it is economically unjustified to use an
ideal scheme of protection and compromise method
has to be adopted.
F. Economy


 As a rule, the protective gear should not cost more
than 5% of total cost. However, when the apparatus
to be protected is of utmost importance (example,
generator, main transmission line etc.), economic
considerations are often subordinated to reliability.


I. Current & Voltage Transformer
II. Protective relays
III. Circuit Breakers
IV. Communication Channels
Main components of
protection systems


also called instrument transformers. Their
purpose is to step down the current or voltage of a
device to measurable values,
within the instrumentation measurement range 5A or
1A in the case of a current
transformers (CTs), and 110V or 100V in the case of a
voltage (or potential) trans-
formers (VTs/ PTs). Hence, protective equipment
inputs are standardized within
the ranges above.
I. Current &
Potential/Voltage
Transformer

A device which transforms the current
on the power system from large
primary values to safe secondary
values. The secondary current will be
proportional (as per the ratio) to the
primary current.
Current
Transformer


 A device which transforms
the voltage on the power
system from primary
values to safe secondary
values, in a ratio
proportional to the
primary value.
Potential Transformer
(PT)


are intelligent electronic devices (IEDs) which receive
measured signals from the secondary side of CTs and
VTs and detect whether the
protected unit is in a stressed condition (based on their
type and configuration) or
not. A trip signal is sent by protective relays to the
circuit breakers to disconnect
the faulty components from power system if necessary.
II. Protective relays


 Protective relays monitor the current and/or voltage
of the power system to detect problems with the
power system. Currents and voltages to relays are
supplied via CT’s and PT’s.


 switching device which can be operated manually as
well as automatically for controlling and protection
of electrical power system respectively.
III. Circuit Breakers


Let us consider for the moment only the relaying
equipment for the protection against
short circuits. There are two groups of such equipment
one which we shall call primary
relaying, and the other back-up relaying. Primary
relaying is the first line of defense,
whereas back-up relaying functions only when
primary relaying fails.
FUNDAMENTAL
PRINCIPLES OF
PROTECTIVE RELAYING


 protective relays are categorized depending
on the component which are protect:
A. generators,
B. transmission lines,
C. transformers, and
D. loads.
IMPLEMENTATION OF PROTECTIVE
RELAYS IN POWER SYSTEMS


There are different protection schemes used for
protecting generators depending on type
of fault to which they are subjected. One of the most
common faults is the sudden loss of
large generators, which results in a large power
mismatch between load and generation.
This power mismatch is caused by the loss of
synchronism in a certain generator - it is
said that the unit goes out-of-step.
A. Generator Protection


In this case, an out-of-step relay can be employed
to protect the generator in the event of these unusual
operating conditions, by isolating
the unit from the rest of the system. In addition,
microprocessor-based relays have a
built-in feature for measuring phase angles and
computing the busbar frequency from the
measured voltage signal from the VT [2]. Thus, phase
angles and frequency measurements
are also available for use within the relay.

Transmission lines can be protected by
several types of relays, however the most
common
practice to protect transmission lines is to
equip them with distance relays.
Distance relays are designed to respond
change in current, voltage, and the phase
angle between
the measured current and voltage.
B. Transmission Line Protection


The operation principle relies on the proportionality
between the distance to the fault and the impedance
seen by the relay. This is done
by comparing a relay’s apparent impedance to its pre-
defined threshold value.


Most of today’s microprocessor- based relays implement
multi-functional protection
features. They are considered as a complete protection
package in a single unit. In
case of line protection via distance protection schemes,
microprocessor-based relays also
provide over current protection, directional over current
protection (for selectivity in case
of multiple parallel lines), under/over voltage protection,
breaker failure protection (in
case the breaker fails to trip even after receiving the trip
command)


distance relay protection
https://www.youtube.com/watch?v
=rYU2s6tJ9Ck&pbjreload=10

February 7 , 2018
Lecture 3
IIEE ZN CHAPTER


The power transformer protection is realized with two
different kinds of devices, namely the devices that are
measuring the electrical quantities (current-based
differential protection) affecting the transformer through
instrument transformers and the devices that are
indicating the status of the physical quantities (latter oil
temperature monitoring) at the transformer itself.
Power Transformer
Protection


 Bayer 69KV Substation Transformer


 What is the name of the oil is used in transformer?
 Insulating oil in an electrical power transformer is
commonly known as transformer oil. It is normally
obtained by fractional distillation and subsequent
treatment of crude petroleum. That is why this oil is
also known as mineral insulating oil.
Food for the Mind…


1. Buchholz (Gas) Relay
2. Pressure Relay
3. Oil Level Monitor Device
4. Winding Thermometer
Protection Devices


 The Buchholz protection is a mechanical fault
detector for electrical faults in oil-immersed
transformers. The Buchholz (gas) relay is placed in
the piping between the transformer main tank and
the oil conservator. The conservator pipe must be
inclined slightly for reliable operation.
 Often there is a bypass pipe that makes it possible
to take the Buchholz relay out of service.
1. Buchholz (Gas) Relay


 The Buchholz protection is a fast and sensitive fault
detector. It works independent of the number of
transformer windings, tap changer position and
instrument transformers. If the tap changer is of the
on-tank (container) type, having its own oil
enclosure with oil conservator, there is a dedicated
Buchholz relay for the tap changer.


 The relay is particularly effective in case of:
 1. Falling oil level owing to leaks
 2. Short circuited core laminations
 3. Short – circuits between phases
 4. Broken-down core bolt insulation
 5. Earth faults
 6. Bad contacts
 7. Puncture of bushing insulators inside tank
 8. Overheating of some part of the windings
Protection Range


In the event of a fault, oil or insulations
decomposes by heat, producing gas or
developing an impulse oil flow. To detect
these phenomena, a Buchholz relay is
installed between the transformer oil tank
and the conservator, so that, upon a fault
development inside a oil transformer, an
alarm is set off or the transformer is
disconnected from the circuit.

 A typical Buchholz protection
comprises a pivoted float (F) pivoted
float (F) and a and a pivoted pivoted
vane (V) vane (V) as shown in Figure
1. The float carries one mercury switch
and the as shown in Figure 1. The float
carries one mercury switch and the
vane also carries another mercury
switch. Normally, the casing is filled
with oil vane also carries another
mercury switch. Normally, the casing
is filled with oil and the mercury
switches are open.

 Gases produced by minor faults rise from
the fault location to the top of the
transformer.
 Then the gas bubbles pass up the piping to
the conservator.
 The gas bubbles will be tapped in the
casing of the Buchholz protection.
 This means that the gas replaces the oil in
the casing. As the oil level falls, the float (F)
will follow and the mercury switch tilts
and closes an alarm circuit.
When minor fault occurs within the
transformer…


major fault- either to earth of
between phases or windings,
occurs within the transformer.
Such faults rapidly produce
large volumes of gas (more than
50 cm3/(kWs) and oil vapor
which cannot escape. They
therefore produce a steep (Of a
slope; set at a high angle) buildup
of pressure and displace oil.
When Major fault occurs within the
transformer…1


This sets up a rapid flow from
the transformer towards the
conservator. The vane (V)
responds to high oil and gas flow
in the pipe to the conservator. In
this case, the mercury switch
closes a trip circuit. The
operating time of the trip contact
depends on the location of the
fault and the magnitude of the
fault current
When Major fault occurs within the
transformer…2


 Tests carried out with simulated operating conditions
have shown that operation in the time range 0.050-0.10
seconds is possible. The operating time should not exceed
0.3 seconds.


The gas accumulator
relay also provides a
long-term
accumulation of
gasses associated
with overheating of
various parts of the
transformer
conductor and
insulation systems.
This will detect fault
sources in their
early stages and
prevent significant


When the transformer is first put into
service, the air trapped in the windings
may give unnecessary alarm signals. It is
customary (Commonly used or practised;
usual) to remove the air in the power
transformers by vacuum treatment during
the filling of the transformer tank with oil.
The gas accumulated without this
treatment will, of course, be air, which can
be confirmed by seeing that it is not
inflammable.


Many power transformers
with an on-tank-type tap
changer have a pressure
protection for the separate tap
changer oil compartment. This
protection detects a sudden
rate-of-increase of pressure
2. Pressure Relay


When the pressure in front of the piston exceeds the
counter force of the spring, the piston will move
operating the switching contacts. The micro switch
inside the switching unit is hermetically sealed and
pressurized with nitrogen gas.


 An internal fault in an oil-filled transformer is
usually accompanied by overpressure in the
transformer tank.


The simplest form of pressure relief
device is the widely used frangible disk.
The surge of oil caused by a heavy
internal fault bursts the disk and allows
the oil to discharge rapidly. Relieving and
limiting the pressure rise prevent
explosive rupture of the tank and
consequent fire. Also, if used, the separate
tap changer oil enclosure can be fitted
with a pressure relief device.


A drawback of the frangible disk is that the oil
remaining in the tank is left exposed to the
atmosphere after a rupture. This is avoided in a
more effective device, the pressure relief valve,
which opens to allow the discharge of oil if the
pressure exceeds the pre-adjusted limit.


 By providing the transformer with a pressure relief
valve, the overpressure can be limited to a
magnitude harmless to the transformer.


If the abnormal pressure is relatively
high, this spring-controlled valve can
operate within a few milliseconds and
provide fast tripping when suitable
contacts are fitted. The valve closes
automatically as the internal pressure
falls below a critical level.


Transformers with oil
conservator(s) (expansion tank)
often have an oil level monitor.
Usually, the monitor has two
contacts for alarm. One contact
is for maximum oil level alarm
and the other contact is for
3. Oil Level Monitor
Device


What is BDV in transformer oil?
Dielectric strength of transformer oil is also
known as breakdown voltage of
transformer oil or BDV of
transformer oil. Break down voltage is
measured by observing at what voltage,
sparking straits between two electrodes
emerged in the oil, separated by specific
gap.


 A typical outlook of an oil level monitor device


The top-oil thermometer has a liquid
thermometer bulb in a pocket at the
top of the transformer. The
thermometer measures the top-oil
temperature of the transformer. The
top-oil thermometer can have one to
four contacts, which sequentially close
at successively higher temperature.


With four contacts fitted, the two
lowest levels are commonly used to
start fans or pumps for forced cooling,
the third level to initiate an alarm and
the fourth step to trip load breakers or
de-energize the transformer or both.


The figure shows the construction of a
capillary-type top-oil thermometer,
where the bulb is situated in a “pocket”
surrounded by oil on top of the
transformer. The bulb is connected to the
measuring bellow inside the main unit
via a capillary tube. The bellow moves
the indicator through mechanical
linkages, resulting in the operation of
the contacts at set temperatures.


The top-oil temperature may be
considerably lower than the
winding temperature, especially
shortly after a sudden load
increase. This means that the top-
oil thermometer is not an effective
overheating protection.


However, where the policy towards
transformers’ loss of life
permits, tripping on top-oil
temperature may be satisfactory. This
has the added advantage of directly
monitoring the oil temperature to
ensure that it does not reach the flash
temperature.


What is transformer oil testing?
To assess the insulating property of
dielectric transformer oil, a sample of the
transformer oil is taken and its
breakdown voltage is measured. The
lower the resulting breakdown voltage,
the poorer the quality of the transformer
oil. The transformer oil is filled in the
vessel of the testing device.


 The winding thermometer, shown in the figure below,
responds to both the top-oil temperature and the heating
effect of the load current.
 Figure 8 – Capillary type of winding thermometer
4. Winding Thermometer


The winding thermometer creates an
image of the hottest part of the
winding. The top-oil temperature is
measured with a similar method as
introduced earlier. The measurement is
further expanded with a current signal
proportional to the loading current in
the winding.


This current signal is taken from a current
transformer located inside the bushing of
that particular winding. This current is
lead to a resistor element in the main unit.
This resistor heats up, and as a result of
the current flowing through it, it will in its
turn heat up the measurement bellow,
resulting in an increased indicator
movement.


 Figure 9 – Top-oil thermometer and winding
thermometer main units fitted on the side of a power
transformer


The temperature bias is proportional to
the resistance of the electric heating
(resistor) element.
The result of the heat run provides data to
adjust the resistance and thereby the
temperature bias. The bias should
correspond to the difference between the
hot-spot temperature and the top-oil
temperature.


The time constant of the heating of the
pocket should match the time constant
of the heating of the winding.
The temperature sensor then measures
a temperature that is equal to the
winding temperature if the bias is equal
to the temperature difference and the
time constants are equal.


The winding thermometer can
have one to four contacts, which
sequentially close at successively
higher temperature.


With four contacts fitted, the two lowest
levels are commonly used to start fans or
pumps for forced cooling, the third
level to initiate an alarm and the fourth
step to trip load breakers or de-energize
the transformer or both.


In case a power transformer is
fitted with top-oil thermometer
and winding thermometer, the
latter one normally takes care
of the forced cooling control.


 Pilot cables are used for control, protection, signalling,
telecommunications and data transmission purposes
 associated with power distribution and transmission systems.
 Such systems are mainly operated by the electrical supply
industry and similar applications occur in many
 industrial systems.
 Pilot cables are insulated with special materials which are
designed to protect them from the danger of induced
 voltages coming from other cable circuits in close proximity (for
example, faults in high voltage power cable circuits).
 An over voltage in the pilot cable cores may compromise alarm
systems, prevent the proper operation of protection equipment,
resulting in severe damage to the power system.
Pilot Cables

February 26 , 2018
Lecture 4
IIEE ZN CHAPTER


The relays used in power system protection are
of different types. Among them differential
relay is very commonly used relay for
protecting transformers and generators from
localised faults. Differential relays are very
sensitive to the faults occurred within the zone
of protection but they are least sensitive to the
faults that occur outside the protected zone.
Differential Relay


 Most of the relays operate when any quantity
exceeds beyond a predetermined value for example
over current relay operates when current through it
exceeds predetermined value. But the principle of
differential relay is somewhat different. It operates
depending upon the difference between two or more
similar electrical quantities.


 There are mainly two types of differential relay
depending upon the principle of operation.
1. Current Balance Differential Relay
2. Voltage Balance Differential Relay
Types of Differential Relay


 In current differential relay two current transformers are
fitted on the either side of the equipment to be protected.
The secondary circuits of CTs are connected in series in
such a way that they carry secondary CT current in same
direction. The operating coil of the relaying element is
connected across the CT’s secondary circuit. Under
normal operating conditions, the protected equipment
(either power transformer or alternator) carries normal
current. In this situation, say the secondary current of CT1
is I1 and secondary current of CT2 is I2. It is also clear
from the circuit that the current passing through the relay
coil is nothing but I1-I2.
1. Current Balance Differential Relay


 As we said earlier, the current transformer’s ratio and
polarity are so chosen, I1 = I2, hence there will be no
current flowing through the relay coil. Now if any fault
occurs in the external to the zone covered by the CTs,
faulty current passes through primary of the both current
transformers and thereby secondary currents of both
current transformers remain same as in the case of normal
operating conditions. Therefore at that situation the relay
will not be operated. But if any ground fault occurred
inside the protected equipment as shown, two secondary
currents will be no longer equal. At that case the
differential relay is being operated to isolate the faulty
equipment (transformer or alternator) from the system.
Current Balance Differential Relay


1. There may be a probability of mismatching in cable
impedance from CT secondary to the remote relay
panel.
2. These pilot cables’ capacitance causes incorrect
operation of the relay when large through fault
occurs external to the equipment.
3. Accurate matching of characteristics of current
transformer cannot be achieved hence there may be
spill current flowing through the relay in normal
operating conditions.
Disadvantages of current differential relay


 This is designed to response to the differential current in
the term of its fractional relation to the current flowing
through the protected section. In this type of relay, there
are restraining coils in addition to the operating coil of the
relay. The restraining coils produce torque opposite to the
operating torque. Under normal and through fault
conditions, restraining torque is greater than operating
torque. Thereby relay remains inactive. When internal
fault occurs, the operating force exceeds the bias force and
hence the relay is operated. This bias force can be
adjusted by varying the number of turns on the
restraining coils.
Percentage Differential Relay


 As shown in the figure below, if I1 is the secondary
current of
 CT1 and I2 is the secondary current of CT2 then
current through the operating coil is I1 - I2 and
current through the restraining coil is (I1+ I2)/2. In
normal and through fault condition, torque
produced by restraining coils due to current (I1+
I2)/2 is greater than torque produced by operating
coil due to current I1- I2 but in internal faulty
condition these become opposite. And the bias
setting is defined as the ratio of (I1- I2) to (I1+ I2)/2


 It is clear from the above explanation, greater the
current flowing through the restraining coils, higher
the value of the current required for operating coil to
be operated. The relay is called percentage relay
because the operating current required to trip can be
expressed as a percentage of through current.


 CT Ratio and Connection for Differential Relay
 This simple thumb rule is that the current
transformers on any star winding should be
connected in delta and the current transformers on
any delta winding should be connected in star. This
is so done to eliminate zero sequence current in the
relay circuit. If the CTs are connected in star, the CT
ratio will be In/1 or 5 A CTs to be connected in delta,
the CT ratio will be In/0.5775 or 5×0.5775 A


 In this arrangement the current transformer are
connected either side of the equipment in such a
manner that EMF induced in the secondary of both
current transformers will oppose each other. That
means the secondary of the current transformers
from both sides of the equipment are connected in
series with opposite polarity. The differential relay
coil is inserted somewhere in the loop created by
series connection of secondary of current
transformers as shown in the figure.
2. Voltage Balance Differential Relay


 In normal operating conditions and also in through fault
conditions, the EMFs induced in both of the CT secondary
are equal and opposite of each other and hence there
would be no current flowing through the relay coil. But as
soon as any internal fault occurs in the equipment under
protection, these EMFs are no longer balanced hence
current starts flowing through the relay coil thereby trips
circuit breaker. There are some disadvantages in the
voltage balance differential relay such as a multi tap
transformer construction is required to accurate balance
between current transformer pairs.


 The system is suitable for protection of cables of
relatively short length otherwise capacitance of pilot
wires disturbs the performance. On long cables the
charging current will be sufficient to operate the
relay even if a perfect balance of current transformer
achieved. These disadvantages can be
 eliminated from the system by introducing Translay
system/scheme which is nothing but modified
balance voltage differential relay system. Translay
scheme is mainly applied for differential protection
of feeders.


 Here, two sets of current transformers are connected
either end of the feeder. Secondary of each current
transformer is fitted with individual double winding
induction type relay. The secondary of each current
transformer feeds primary circuit of double winding
induction type relay. The secondary circuit of each relay
is connected in series to form a closed loop by means of
pilot wires. The connection should be such that, the
induced voltage in secondary coil of one relay will oppose
same of other. The compensating device neutralizes the
effect of pilot wires capacitance currents and effect of
inherent lack of balance between the two current
transformers.


 Under normal conditions and through fault conditions,
the current at two ends of the feeder is same thereby the
current induced in the CT’s secondary would also be
equal. Due to these equal currents in the CT’s secondary,
the primary of each relay induce same EMF.
Consequently, the EMF induced in the secondaries of the
relay is also same but the coils are so connected, these
EMFs are in opposite direction. As a result, no current
will flow through the pilot loop and thereby no operating
torque is produced either of the relays. But if any fault
occurs in the feeder within the zone in between current
transformers, the current leaving the feeder will be
different from the current entering into the feeder.


 Consequently, there will be no equality between the currents in
both CT secondaries. These unequal secondary CT currents will
produce unbalanced secondary induced voltage in both of the
relays. Therefore, current starts circulating in the pilot loop and
hence torque is produced in both of the relays. As the direction
of secondary current is opposite into relays, therefore, the
torque in one relay will tend to close the trip contacts and at the
same time torque produced in other relay will tend to hold the
movement of the trip contacts in normal un-operated position.
The operating torque depends upon the position and nature of
faults in the protected zone of feeder. The faulty portion of the
feeder is separated from healthy portion when at least one
element of either relay operates. This can be noted that in
translay protection scheme, a closed copper ring is fitted with
the Central limb of primary core of the relay.


 These rings are utilised to neutralise the effect of pilot
capacity currents. Capacity currents lead the voltage
impressed of the pilot by 90o and when they flow in low
inductive operating winding, produce flux that also leads
the pilot voltage by 90o. Since
 the pilot voltage is that induced in the secondary coils of
the relay, it lags by a substantial angle behind the flux in
the field magnetic air gap. The closed copper rings are so
adjusted that the angle is approximately 90o. In this way
fluxes acting on the disk are in phase and hence no torque
is exerted in the relay disc.


FMPR-108 l Transformer
Protection v2


Electrical loads are commonly
sensitive to the voltage variations
which can cause serious load
damages when high voltage
fluctuations arise. In that case, loads
can be protected by using
over/under voltage relays.
Load Protection


Overvoltage relay is a relay
that operates when its input
voltage is higher than a
predetermined value.
Overvoltage relay- device #59


Undervoltage relay is a relay that
operates when its input voltage is
less than a predetermined value.
Undervoltage relay- device # 27


GE:
– ENERVISTA UR and ENERVISTA MII are Windows-
based softwares that
allow users to communicate with relays for data
review and retrieval,
oscillography, I/O configurations and logic
programming.
Short description of Programming and
Software Features
from different vendors


SEL:
– ACSELERATOR QuickSet Software provides analysis
support for
SEL-relays. It creates, tests, and manages relay settings with
a Windows
interface.
– SEL-5077 SYNCHROWAVE Server provides phasor data
concentration
(PDC) for synchrophasor information, and transmit data to
a display
software in IEEE C37.118 format.


ALSTOM:
– MICOM S1 Studio provides user with global access to
all IEDs data by
sending and extracting relay settings. It is also used for
analysis of events
and disturbance records which acts as IEC 61850 IED
configurator.


ABB:
– IED Manager PCM 600 is the toolbox for control and
protection IEDs. It
covers the process steps of the IEDs life cycle, testing,
operation and
maintenance, to the support for function analysis after
primary system faults.


CAP 505 Relay Product Engineering Tool is a graphical
programming tool
for control and protection units. It can be used both as
a local system near
the relay and as a central system connected to several
relays.
– RELTOOLS is management tool for controlling relays
of the ABB-family. It
allows the user to edit settings and to modify control
logics.
-ABB


A communication system consists of a transmitter, a
receiver and communication
channels. Type of medias and network topologies in
communications provide different opportunities to
advance the speed, security, dependability, and
sensitivity of protection
relays.
IV. Communications in
power system protection


There are a few types of communication media such as
micro wave, radio system, fiber optic, etc. The
advantages and disadvantages in communication
medias which are currently in operation (both analog
and digital) and different network
topologies are summarized


Power System Protective Relaying:
basic concepts, industrial-grade
devices, and communication
Mechanisms
 Rujiroj Leelaruji
 Dr. Luigi Vanfretti
 Relay symbols and device function number (ABB)
 The art and science of protective relaying- Russell
Mason-General Electric (GE)
Sources:


Future
Electrical
Engineer’s!
Be sure to wire
your brains
correctly
Electrical Engineer’s brain

The End!
Thank You!
EE 528
PROTECTIVE RELAYING
Class of 2018

Protective relaying

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