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e-ISSN: 2582-3000
Volume-7, Issue-3 (September-December, 2021)
Journal of
Control and Instrumentation Engineering
www.matjournals.com
Review on Electrical Protection Systems for Chemical and Biological
Laboratory Equipment
Dr. Nagham Mahmood Aljamali*1, Dr. Khudheyer Abbas Aziz Alnomani2, Dr. Maysaa A Alhar3
1*Professor, Ph.D in Organic Chemistry, Synthetic Chemistry Field, Iraq
2Lecturer, Plant Protection Department Faculty of Agriculture University of Kufa, Iraq
3Lecturer, Horticulture Department, Faculty of Agriculture, University of Kufa, Iraq
Corresponding Author: dr.nagham_mj@yahoo.com
ABSTRACT
The review was associated with electrical
protection systems for chemical laboratories,
dealing with the protection of electrical power
networks (transmission networks,
distribution networks) from faults by
isolating the faulty parts of the electrical
network. The goal of the protection system is
to maintain a stable system by isolating the
faulty part only through electrical protection
devices for chemical equipment in
laboratories, so as to ensure continuity of
current in other parts of the electrical
network within the laboratory equipment.
Thus, protection plans should be applied to a
practical and scientific approach to properly
eliminate system failures. That is why it is
recommended to unwind the cable when
passing by a large current. Many materials or
laboratory equipment resist the passage of
electricity.
Keywords-- safety, chemical advices, protection
INTRODUCTION
Power systems deliver power to loads
that perform a function. This group loads
household appliances or industrial machinery.
Most loads require a specific voltage, and for
AC current devices, a certain frequency and
number of phases are required. Appliances in the
home, for example, usually need single phase
operating at 50 or 60 Hz and voltages between
110 and 260 volts (depending on national
standards). Except for the presence of central air
conditioning systems these are now usually of
three phases because this allows them to operate
more efficiently [1]. All appliances in your home
will also have a wattage, and this determines the
amount of energy the appliance consumes. At
any one time, the total amount of energy
consumed by the loads on the power system
must be equal to the total amount of energy
produced by the generators and is less than the
energy lost during transmission.
It must be ensured that the voltage,
frequency and amount of power supplied to the
loads are in line with the requirement, which is
one of the major challenges of power systems
engineering. But this is not the only challenge, in
addition to the energy being consumed by the
load to do useful work (which is called true
capacity), many AC current devices also use an
additional amount of power because it causes the
AC current and AC voltage to become slightly
off Synchronicity i.e. not synchronous (which is
called reaction force). Reactive capacity such as
true capacity must be balanced (the reaction
capacity produced by the system must equal the
power consumed at the load) and this can be
supplied by generators, but it is often more
economical to provide such capacity from
capacitors (see 'Capacitors and reactors' below
for more details), final consideration with loads
is energy efficiency. In addition to (overload
issues) and (voltage regulation issues) as well as
continuous deviations from the frequency system
(frequency regulation issues), the power system
can be affected by a range of temporary issues
[2, 3]. These include voltage drops, dips and
amplifications, over voltages, transient
flickering, high frequency noise, phase
imbalance and poor power factor. Many quality
issues occur when power supplies to a load
deviate from the ideal for an AC supply. The
ideal is to obtain current and voltage in
Coincidence, that is, both of them have the same
phase, provided that the prescribed frequencies
are compatible with the voltage and amplitude.
The ideal is efforts not varying from the
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e-ISSN: 2582-3000
Volume-7, Issue-3 (September-December, 2021)
Journal of
Control and Instrumentation Engineering
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specified level of supply of loads. Issues related
to power quality may be of particular importance
when it comes to specialized industrial
machinery or hospital equipment [4].
The importance of electrical protection
The importance of electrical protection
lies in: Reducing equipment damage from
overvoltage or heat that may result during a
malfunction., Preventing or minimizing damage
to persons nearby or working on the equipment.,
To ensure the continuity of the electric current.,
To ensure the stability of the generators., Basic
components of electrical protection systems.,
Electrical protection systems mostly consist of
five main components: Voltage transformers and
current transformers, which reduce the high
voltages and currents of the electrical system to
low values that are proportional to the relays.
Relays: which sense a malfunction and give an
order to disconnect or disconnect the electrical
circuit.
Circuit breakers (circuit breakers): which open
or close the electrical circuit and are connected
with the relays so that they receive opening
orders from the relay in the event of a
malfunction or an increase in current...etc) and
that is due to the type of relay [5].
Communication channels, which
analyze currents and voltages from a distance,
search and give the necessary signals to
disconnect the circuit in the event of a fault. For
parts of distribution networks, fuses are able to
sense and disconnect the circuit in the event of a
fault. The malfunction may occur in any part of
the electrical network, such as: insulation
breakdown, transmission line cuts, faulty
operation of the circuit breaker, short circuit or
open circuit. Protection devices are installed to
provide the necessary protection for devices and
people, and also to ensure that the power is not
cut off in the event of faults. Laboratories and
residential buildings often take the supply from
the low-voltage distribution lines or cables that
supplied the home in the past. These operate on
voltages between 110 and 260 volts (phase to
earth) depending on national standards. A few
decades ago, small dwellings were fed in single
phase using dual-core service cables (one core
for active phase and one core for neutral). The
active line then runs through an isolated main
switch in the fuse box and this split into one or
more circuits to feed the lighting and appliances
circuits inside the house. By agreement, lighting
circuits and appliances will remain separate, so
failures in appliances will not leave occupants in
the dark. All circuits will be connected to an
appropriate common fuse depending on the size
of the wire used for that circuit. All circuits will
have an active and drawn wire with both lighting
and power sockets connected in parallel. Sockets
with protective ground will also be provided.
These tools will be available to connect to any
metal casing. If this casing is to be true, the
theory is that the connection to the ground will
trigger the residual current device or the valve to
operate—thus preventing electrocution of the
static while it deals with future devices.
Grounding systems vary between regions, but in
countries such as the UK and Australia both the
protective earth and the neutral line will be
grounded together near the fuse box before the
isolated main switch and the neutral ground back
into the distribution transformer.
A number of minor changes occur in the
performance of residential wiring throughout the
year. The most important means in modern
residential energy systems tend to differ from
their old counterparts, and the most prominent of
those differences are: Because of convenience,
MCBs are currently the most commonly used in
the fuse box rather than the fuse itself, as they
can be easily reset by their occupants., For safety
reasons, residual current devices are now being
installed on instrument circuits and, increasingly,
even on lighting circuits. Houses are usually
connected to the three phases of the distribution
system, with phases randomly assigned to the
single-phase house circuits. Whereas in the past
air conditioners might have been fed by circuits
connected to a single phase, central air
conditioners that required three-phase power are
now commonplace., Protective floors currently
work with lighting circuits to allow metal lamp
holders to connect to the ground., Residential
growing power systems are compact miniature
generators, most notably photovoltaic cells [6-8].
Laboratory Equipment Protection Systems
Power systems contain protective
devices to prevent injury or damage during
failure. The ideal protective device is a fuse or
an electric fuse. When the current through the
fuse exceeds a certain threshold, the fuse
element fuses, producing an arc across the
resulting gap which is then extinguished, cutting
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e-ISSN: 2582-3000
Volume-7, Issue-3 (September-December, 2021)
Journal of
Control and Instrumentation Engineering
www.matjournals.com
the circuit. The construction of fuses can also be
considered as a weak point of the system, fuses
are ideal for protecting circuits from damage.
But despite this there are two problems with the
valves: first, after they have worked, they must
be replaced because they cannot be reset. This
may be inconvenient if the fuse is in a remote
location or fuse parts are not within reach [9].
The second is that it is usually insufficient as the
only safety device in most control systems, since
it allows a good flow of current well in excess of
that which would kill a human or animal. The
first problem was solved by using circuit
breakers - devices that can be reset after the
current flow has been cut off. In modern systems
that use less than about 10 kW, miniature circuit
breakers are usually used. These devices
combine a mechanism that starts a trip (by
sensing an excess of current), as well as a
mechanism that breaks the flow of current into a
single unit. In these miniature circuit breakers,
current is run through a solenoid and, if
excessive current flow occurs, the magnetic
solenoid draws enough force to open the wave
contacts in the circuit (often indirectly through a
tripping mechanism). The best design is created
by inserting a bimetallic strip before the
solenoid—this means that instead of
permanently producing magnetic force, in higher
power applications, there are protective relays
that detect the fault and initiate a trip separate
from the circuit breaker. Early relays worked on
the basis of electromagnetic principles similar to
those mentioned in the previous paragraph,
modern relays are an application of computers
that determine whether to trip based on readings
from the power system [9, 10]. The flights of
different relays will start depending on the
different protection programs. For example, an
overcurrent relay may start a trip if the current in
any phase exceeds a certain threshold, and since
it is a group of relays the difference may start a
trip if the sum of the currents between them
indicates that there is current leakage to ground.
Circuit breakers in various applications are very
high powered. Air is usually no longer sufficient
to quench the arc that forms when connections
are forced open until a variety of techniques are
used. The most popular method at the moment is
to have the chamber containing the connections
flooded with sulfur hexafluoride (SF6) - a non-
toxic gas that has high arc suppression properties
[11].
The second problem, insufficient fuses
to serve as the sole safety device in most power
systems, is best resolved through the use of
residual current devices (RCDs). In properly
working electrical appliances, the current
flowing in active devices on a line is equal to the
current flowing from devices on the neutral line.
A residual current device works by monitoring
active and neutral lines. Active lines trip if they
sense a difference. Residual current devices
require a separate line for each neutral phase and
are able to trip within a time schedule before
damage occurs. This is usually not a problem in
most residential applications since standard
wiring provides an active and neutral line to all
devices (which is why you have at least two
pickups in your power sockets) and is relatively
low voltage but these issues do not limit the
effectiveness of residual current devices in other
applications like industry. Even with the
assembly installed, exposure to fatal electricity
can inevitably be done [12-14].
Power Generators for Chemical Laboratory
Equipment
All power systems have one or more
energy sources. For some power systems, the
energy source is outside the system but for
others it is part of the system itself and these are
the internal energy sources discussed in the
remainder of this section. DC power can be
supplied directly from batteries, fuel cells or
photovoltaic cells. The alternating current in the
current period is usually supplied by a rotor that
rotates in a magnetic field in a device known as
a turbine generator in a power plant. There have
been a wide variety of technologies used in
rotating a turbine, from steam heated with fossil
fuels (including gas, coal and oil) or nuclear
power, or falling water (hydroelectricity) and
wind (wind power) [13]. The speed at which the
rotor rotates in combination with the number of
poles of the generators determines the frequency
of the alternating current produced by the
generators. All generators are on one system, eg
the national grid (in the UK) rotates
synchronously (ie at a similar average speed),
thus targeting frequency tuning, in European
countries the common frequency is 50 Hz. If the
system load increases, the generators will require
more torque to increase the current and speed in
a conventional power plant, they must provide
more thrust for their turbines. The amount of
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e-ISSN: 2582-3000
Volume-7, Issue-3 (September-December, 2021)
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Control and Instrumentation Engineering
www.matjournals.com
electrical energy produced depends on both the
fuel that is burned and the steam that is produced
from it. It also depends on how the poles are fed:
alternating current generators produce a variable
number of phases. The higher number of phases
increases the energy efficiency of the operating
system, but it also increases the requirements for
the infrastructure of the system. The power grid
connects multiple generators as well as loads
that operate at the same frequency and number
of phases, most commonly being on three phases
at a frequency of 50 or 60 Hz. But there are
other considerations. It is obvious how much
power can a generator supply? How long does it
take for a generator to start working (some
generators can take hours to start)? Is the
availability of acceptable energy sources?? For
more tech: How should a generator start? (Some
turbines work like engines to reach speed, in
which case do they need suitable starting
circuits)? What is the mechanical speed to
operate the turbine and therefore how many
poles are required? What type of alternator is
suitable (synchronous or asynchronous) and type
of rotor (squirrel cage rotor, coiled rotor, rotor or
cylindrical protruding pole)? [14-16].
The use of three-phase current in laboratory
equipment:
It is called three-phase because three
currents travel in three wires, and each of these
three currents begins with a phase shifted from
the other by 120 degrees, that is, one third of a
circle as well as other uses, but provided that
there is another party called the tie party.
This system has very large capabilities
and great stability, as well as an excellent
efficiency in the transmission of electricity and
the production of kinetic energy in three-phase
current motors, with efficiency ranging from
80% to 97%. This system was able to meet the
needs of the industrial world by providing safe,
sufficient, and reliable energy. Triple current is
also preferred because of its ability to run
induction motors without the need for starting
and starting means. It can rotate the motor very
quickly and capacities up to 10 times that of
single-phase current motors with an efficiency of
more than 90% [17-19]., The three-phase current
is mainly used to transmit electricity through the
electrical network in order to save material
consumption and for its high efficiency (slight
losses). However, some countries use single-
phase current distribution in their electrical
network, especially to operate electric trains and
metros, and this is due to historical reasons. In
the present era, the single-phase current is used
to transmit the high voltage of the DC due to the
increase in the production of offshore wind
energy in offshore fields to deliver the electric
energy produced to the coasts.
Electricity can be transmitted by high-
power transformers in the form of a three-phase
current in the electrical network at different
levels of electrical voltage - from high pressure
produced in power stations to medium pressure
for transmission to low pressure for use in
homes and factories - with a high efficiency of
up to 99%. In principle, it is also possible to use
three transformers [20], each working with one
phase, to operate motors and devices operating
with three phases of the current. This last
method is used when transportation difficulties
require it in terms of reducing weight and
reducing dimensions. But the application of a
three-phase or five-terminal current transformer
in its iron core also ensures an economical use of
the material [21-24]. By sequencing the
magnetic currents in the three stellar voltages,
the iron core of the transformer can also be
dispensed with. In general, a three-phase current
transformer is distinguished by a lower power
loss in the iron core than three single-phase
transformers to produce the same electrical
power, because the energy loss is proportional to
the mass of the iron core [25-27]. There is also a
special circuit called the "Scotts chaltung"
circuit, which consists of two electrical
transformers. It allows converting three-phase
systems into a two-phase system or into a four-
phase system, provided that the three-phase
system carries the same amount of load. In an
electric power plant, an electric generator
converts kinetic energy into three alternating
currents, each exiting with a cable from each coil
in the generator[28-30]. In a generator, the three
coils are arranged so that they produce the same
frequency as a sine wave, but with arranged
peaks and troughs shifted in time by a third of a
turn, 120°. The frequency coming out of the
power plant is usually 50 Hz and in some
countries the frequency is 60 Hz. In the power
station, electrical transformers convert the
voltage to a high level suitable for
transportation, thus reducing the current lost
during transportation. After several other
conversions by electrical transformers, the
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e-ISSN: 2582-3000
Volume-7, Issue-3 (September-December, 2021)
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Control and Instrumentation Engineering
www.matjournals.com
voltage is reduced to suit consumer use [30, 31],
The three-phase current facilitates the production
of a uniformly rotating magnetic field. Such a
rotating field is used to drive a three-phase
current machine [32,33], which may be a three-
phase motor or an electric generator that
produces electric power. Figures (1-5).
Figure 1: High capacity laboratory equipment
Figure 2: High power laboratory equipment
Figure 3: High Voltage Current Analyzers
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Figure 4: Protection of high-vacuum laboratory equipment
Figure 5: Protect sensitive laboratory equipment
CONCLUSION
The quality of the supremacy is what
determines the suitability of the electrical power
of laboratory and medical electrical equipment.
Voltage-to-current synchronization allows
electrical systems to operate as intended without
significant losses in performance or life. This
term is used to describe the electrical capacity
required for any electrical load, and the ability of
the load to function properly. Without the
correct power, the device or the electrical load
may fail to function, failing at all or not at all.
There are many reasons why the quality of
electrical power is poor. The electric power
industry includes electricity generating stations,
then transporting it over long distances and
distributing it to consumers, and this is enough
to reduce the quality of power if the necessary
precautions are not taken.
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