Design of laboratory experimental Panel of Parallel feeder Protection
The main characteristic of a radial system is that power flow only in one direction, i.e. from the generator or the supply end to the load end of a fault. It has the drawback that continuity of supply cannot be controlled at the load end in the occurrence. The parallel connection of the supp
2025-06-28 16:31:57 - Adil Khan
Design of laboratory experimental Panel of Parallel feeder Protection
Project Area of Specialization Shared EconomyProject SummaryThe main characteristic of a radial system is that power flow only in one direction, i.e. from the generator or the supply end to the load end of a fault. It has the drawback that continuity of supply cannot be controlled at the load end in the occurrence.
The parallel connection of the supply is mainly used for the continuity of the supply and for sharing the load. When the fault occurs on the protective feeder, the protective device will select and isolate the defective feeder while the other instantly assume the increased load.
The simplicity and cost effectiveness of parallel feeder makes its protection much expensive then radial feeder but less expensive then ring main system and interconnected distribution system. But it has continuity of supply during fault conditions.
One of the simplest methods for the protection of the relay is the time graded overload relay with inverse time characteristic at the sending end and instantaneous reverse power or directional relays at the receiving end as shown in the figure below.
When the heavy fault F occur on any one of the lines, then the power is fed into fault from the sending end as well as from the receiving end of the line. The direction of power flow will be reversed through the relay on D, which will be open.
The excess current is then restricted to B until its overload relay operates and trips the circuit breaker, thus completely isolating the faulty feeder and supplying power through the healthy feeder. This method is only satisfactory when the fault is heavy and reverse the power at D. Hence differential protection is also added along with the overloaded protection at both the end of the line.
As per Kirchoff's current law,
IA + IB = If
Project ObjectivesContinuity of power is the most required quality of any power system because there are many appliances that required electric power to carry out their functions. Computer and telecommunication networks, industries, railways, Airports and other organizational offices required the continuous and high value of electricity to carry out their functions properly. No power supply in this world is designed in such a way that it’s never fails. So protection is required for the safety of appliances and continuous flow of electricity. Most important scheme is through parallel feeder.
In power distribution system there are mostly transformers, shunt capacitor banks and protective devices which age over time and the mostly distribution system is over headed which could easily effected by the weather. As the parallel feeder distribution is characterized by more than one line in parallel for power flow from source to consumer end. So for continuous flow of power from source to load end a protection scheme is required to install on a whole system of distribution which results the fast and accurate detection and clearance of fault by isolating the faulty feeder from healthy system and supplies the consumer through the other feeders in parallel.
The proposed project acts as a base in implementation of parallel distribution scheme in Pakistan that will ensure the continuity of supply of electricity during faulty conditions as well as sharing of load through different feeders with full safety.
The proposed project acts as a base to the experimental laboratory which will be effective in the industrial awareness and develop experimental techniques in academic activities of the protection system. Since there is no hardware available in the lab of power system protection, proposed project will act as a foundation stone to the experimental laboratory of power systems. Being one of its kind in this institution emphasis its importance.
The estimation of parallel feeder parameters are performed by standard modeling techniques. When the panel will design which will spontaneously isolate the faulty feeder from the healthy system, this will ensure the sustainable and safe operation of system.
Project Implementation MethodProject Implementation Method:
Proposed project implements a laboratory experimental setup based on Protection of parallel feeders which has modeled each of parallel feeder in two sections, one at sending end and other at receiving end in the form of fixed resistances and a fault line to provide as realistic condition of the fault situation as possible. A protection assembly consisting of IDMT relays, DC relays, inverse power flow relays and magnetic contactors has been setup as a protective measure to the fault.
Main Component Detail
There are Six main components that play a key role in the preparation of the working model of our proposed project. The details of the main component are given as:
Magnetic Contactors:
A magnetic contactor is a n electrical device use for switching of an electrical circuit.it can also be defined as a magnetically operated device which is used to interrupt and establish an electrical flow of power in the circuit. It is basically controlled by a low voltage operated DC based circuit usually 24V to switch the power flow in any electrical circuit.
Auxiliary Relay:
We are using the auxiliary relay in our project to assist the IDMT relay to perform its function of making and breaking the flow of power with the help of contactors. The Auxiliary relay that we are using in our project is 24V DC operated.
The main function of Auxiliary relay in our project is to get a signal from IDMT relay and open its contact so the contactors get a signal from it and perform its function to break the flow under fault conditions.
IDMT Electromagnetic Relay
IDMT is defined as inverse definite minimum time relay which operate on the principle of inverse relation which states that” The operating time of the relay decreases as the current increases” .This is reason that the relay is named as IDMT relay.
In our proposed project, When fault will occur in any of the parallel feeder current of large magnitude will flow from that feeder decreasing the operating time of the IDMT relay and faster generating a signal to auxiliary relay.
Reverse Power Flow Relay
The reverse power relay is a directional protective relay that prevents power from flowing in the reverse direction.
In our proposed project if fault occur in any feeder the power will be fed to the fault location from sending end as well as from receiving end causing reverse power flow. Therefore, this relay will be used at receiving end for switching action when power is reversed that means fault occurred.
Benefits of the ProjectBenefits of the Project:
The main issue in power systems under faulty conditions are protective devices coordination with each other. The proposed project is very effective in coordination between protective devices and detection and isolation of faults in any of the feeder.
- The project can be used in industry as a basic level demonstration of parallel distribution system with all necessary features related to protection.
- Parallel distribution system can be implemented in Pakistan. That will give continuity of supply to the consumer.
- Project can be used as an experimental panel in university level on which students can perform experiments related to protection.
- Project can be used to understand the co-ordination between protective devices.
- Project can be used for research purposes as a experimental model to understand the system behavior during faults.
- Enhance the safety of power system.
- Automatic fault interruption
- Proposed panel can be modified to ring main feeder protection panel.
- No extra wiring required for back-up protection.
- Customization of protection panel as per commercial requirements.
- No extra relay used of to upgrade the system to three phase.
Technical Details of Final Deliverable:
A fully operational Laboratory Experimental Panel for parallel Feeder Protection with:
- Single phase protection scheme panel.
- 220V AC Supply based IDMT Relays and reverse power flow relays, capable of working efficiently 3 phase protection scheme.
- Multi-timing curves with normally inverse, highly inverse and extremely inverse curves, that is to say adaptive curve selection capability for normal, fast and instantaneous tripping.
- Utilized current transformers designing techniques.
- Equipped with very low and readily available 24V DC contactors with contact rating upto 60A, capable to work well with load up to 15KW.
- High Power resistor rated up to 20A wired with high Ampacity cables.
- Class A insulation level avoiding panel box shorting ultimately reduce electric shocks risks while handling.
| Item Name | Type | No. of Units | Per Unit Cost (in Rs) | Total (in Rs) |
|---|---|---|---|---|
| Total in (Rs) | 69250 | |||
| overcurrent relays | Equipment | 4 | 10000 | 40000 |
| Current Transformers | Equipment | 4 | 1000 | 4000 |
| magnetic contactors | Equipment | 4 | 800 | 3200 |
| DC Power sopply | Equipment | 1 | 600 | 600 |
| Panel Board | Equipment | 1 | 10000 | 10000 |
| Arduino Uno | Equipment | 1 | 800 | 800 |
| Wooden Box | Equipment | 1 | 1200 | 1200 |
| Power resistor | Equipment | 4 | 600 | 2400 |
| Ammeter | Equipment | 4 | 650 | 2600 |
| Voltmeter | Equipment | 1 | 650 | 650 |
| Auxiliary Relay | Equipment | 4 | 400 | 1600 |
| Push Button | Equipment | 15 | 120 | 1800 |
| DC Alarm | Equipment | 1 | 400 | 400 |