PLC based Transformer monitoring

1. Health monitoring of transformer
using PLC
By :
Rohithsai S

2. Existing systems of transformer monitoring
 GSM based monitoring system :
Disadvantages:-
1. It involves a large number of components
that results in complexity of the system.
2.It works with the help of mobile network so
that it may not work when there is any disturbance
in mobile network.


3. PLC based transformer monitoring
 Before going to discuss this PLC based monitoring system, let us have a look
at the various types of faults that a transformer usually undergoes :-
 Overvoltage fault,
 Undervoltage fault,
 Overcurrent fault,
 Undercurrent fault,
 Over temperature fault,
 Oil leakage fault,
 Phase to Phase fault.
 Phase to Neutral fault.
Hence, there is a great need to monitor the above faults continously and to
disconnect the transformer from the circuit automatically.

4. Hardware required for the prototype model
 Three phase transformer :
It is used to step down the phase
voltage of 230v to a voltage of 12v.
 Relays :
A number of 3 basic electromechanical
relays are employed at the primary side of 3
phases.
 Transducers :
This model consists of 3 types of
Transducers like voltage, current and
temperature transducers.

5. (Cont.)
 Rectifier circuit :
This circuit is used to convert the 12v ac to
12v dc in order to supply the transducers.
 PLC System :
Here in this prototype, we have employed
a PLC device Schneider electrics.
 Power supply :
This model needs a 3 phase power supply
of 230v to feed the 3 phase transformer.
 Load :
A number of 10 led’s has been used here which acts as
load on the 3 phase transformer.

6. Schematic arrangement of PLC system

7. Ladder logic in the proposed system :

8. HMI interfacing :
1. The over current condition 2. The overvoltage and overload
conditions

9. How voltage variations are produced in this model ?
Ans : Using Autotransformer
• An autotransformer (sometimes called auto step
down transformer) is an electrical transformer with
only one winding. In an autotransformer, portions
of the same winding act as both the primary and
secondary sides of the transformer. The winding
has at least three taps where electrical connections
are made. Autotransformers are often used to step
up or step down voltages in the 110-115-120 V
range and voltages in the 220-230-240 volt range
for example. Providing 110 V or 120 V (with taps)
from 230 V input, allowing equipment designed
for 100 or 120 volts to be used with a 230 volt
supply. In this project, autotransformer is used to
change the voltage which analyze to under voltage
fault as well as overvoltage fault.

10. Model of our project :

11. Advantages of the proposed system :
 No need of any man power to monitor the transformer
 It automatically trips the circuit if the transformer encounters any
fault.
 It continously monitors the parameters throughout its operation.
 It also stores the fault parameters for further reference of
maintenance engineers
 It ensures the continuous and reliable power supply to the
consumers.
 It makes the transformer more robust against some power quality
issues.

12. Conclusion :
 This paper presents a design of a system based on PLC that is used to monitor
and control the voltage, current and temperature of a distribution transformer in both
sides. The proposed PLC system which has been designed to monitor the transformer’s
essential parameters, it continuously monitors the parameters throughout its operation
When the PLC recognizes any increase or decrease in the level of voltage, current or
temperature values the unit has been made shutdown in order to prevent it from
further damages with the help of relays in three phase system. The system not only
controls the distribution transformer in the substation by shutting it down, but also
displays the values throughout the process for user’s reference in SCADA system.
This claims that the proposed design of the PLC system makes the distribution
transformer more robust against some key power quality issues which make the
voltage, current or temperature to peak. Hence the distribution is made more secure,
reliable and highly efficient by means of the proposed system.

13. References :
1. A Review of Transformer Protection by Using PLC System -Dr. S. P. Shukla Professor,
(Electrical Engineering),Bhilai Institute of, Technology, Durg, India.
2.Rohan Perera & Bogdan Kasztenny, “Application Considerations When Protecting
Lines With Tapped and In-Line Transformers”, previously presented at 2014 Texas
A&M Conference for Protective Relay Engineers, © 2014 IEEE – All rights
reserved. 20140210, TP6575-01.
3. Monitoring and Controlling of Distribution transformer using PLC, International
Journal of Emerging Research in management and technology IJERMT paper (volume-5)
4. Kipp Yule, Duane Brock, and Jim Purdy, “Accountability and Evaluation of
Aggregate Effects of Through Faults on Power Transformers”.
5. V. Thiyagarajan & T.G. Palanivel, “An Efficient Monitoring Of Substations
Using Microcontroller Based Monitoring System”, IJRRAS 4 (1), July 2010.