DESC:TECHNICAL FIELD OF THE INVENTION

The present invention generally relates to the field of the power distribution system, and more particularly, it relates to a device for protective gear maintenance of any Plant / Feeder in a power distribution system for minimization of the shutdown period during the maintenance process.

BACKGROUND OF THE INVENTION

In Power Distribution system, uninterrupted supply to each consumer is one of the prime objectives. In an exemplary Distribution system approximately 33Lakh of consumers get supply from low voltage (415/230V) side of Distribution Transformer (DTR), and these DTRs are being energized from 11kV or 6kV Feeder switches. There are altogether approx. 1800 numbers of such 6/11kV Feeder fed from around 120 numbers of distribution station.

Normally Preventive maintenance of the protection system of each feeder is scheduled once in three years. For maintenance of each feeder, at least sixty minutes shutdown is required. Approx. 800 LT consumers are being fed from each feeder through 11/6kV/415-230V DTRs. Therefore, for the above Distribution system, yearly on an average 600 to 800 numbers of 6 and 11kV feeder maintenance is being planned to cover 1800 numbers of such feeder now a day’s getting shutdown of a feeder becomes a critical issue in terms of getting interruption from consumers. On the other hand, protective gear maintenance is also of utmost importance in order to prevent protection mal-operation and non-operation / ensure correct operation during fault condition. Organizing shutdown from any consumer has become extremely difficult, as we are moving towards customer-centric approach and negligible downtime. Additionally, shutdown embargoes like Festivals, Exams, summer seasons, VIP Visit etc. have made this Preventive maintenance schedule more difficult and challenging.

Protective gear maintenance of any Plant / Feeder is normally scheduled once in three years. For maintenance of each feeder, at least sixty minutes shutdown is required. In the present scenario, organizing shutdown for any consumer becomes difficult. At present there is no system available for the reduction of shutdown period during the maintenance of the feeder protective gear.

Accordingly, there is a dire need for developing a system for minimization of the shutdown period during the protective gear maintenance of a feeder so as to provide uninterrupted power supply to the consumers.

SUMMARY OF THE INVENTION

The following disclosure presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the present invention. It is not intended to identify the key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concept of the invention in a simplified form as a prelude to a more detailed description of the invention presented later.

An object of the present invention is to overcome the problems associated with the prior arts.

An object of the present invention is to develop a system for minimization of the shutdown period during the protective gear maintenance of a feeder.

An object of the present invention is to achieve revenue savings by providing less shut down time during the protective gear maintenance of a feeder.

Another object of the present invention is 100% adherence to protective gear maintenance schedule.

A further object of the present invention is to provide a customer-centric approach which ultimately provides customer satisfaction.

In accordance with the purposes of the invention, the present invention as embodied and broadly described herein a system and an apparatus for minimization of long duration shutdown period during Protective gear maintenance of 6/11kV feeders in Power Distribution system using ‘Protection Transfer Kit’ (PTK).

Accordingly, an aspect of the present invention is to provide a Protection Transfer Kit (PTK) unit by using which the shutdown time can be reduced from sixty minutes to around five minutes only by transferring the ‘protection system’ of the feeder under maintenance to the “Protection Transfer Kit (PTK)” as disclosed in the present disclosure without taking any shutdown.

Accordingly, an aspect of the present invention is to provide a Protection Transfer Kit (PTK) unit where the protection system of the feeder under maintenance is transferred to "PTK" and the existing protection system of the feeder is made free to carry out necessary maintenance activities. Therefore, providing uninterrupted power supply to the consumers.

In one implementation of the present invention, a system for protection transfer for feeder maintenance in a power distribution system is disclosed which comprises a feeder of the power distribution system comprising a protection system, plurality of numerical relays, a current transformer, plurality of control circuits and a digital meter configured to display the load of the feeder.

In one implementation of the present invention, the system comprises a changeover system and plurality of hard wirings configured to transfer the protection system of the feeder of the power distribution system to a Protection Transfer Kit (PTK) during maintenance of the feeder and the protection system of the feeder is configured to identify the maintenance to be done in the feeder to be serviced.

In one implementation of the present invention, a method of transferring protection for feeder maintenance in a power distribution system is disclosed and the said method comprises steps of identifying the maintenance to be done in a feeder, connecting wires to a PTK for a control transformer and plurality of control circuits, measuring and monitoring of feeder parameters and transferring of a feeder protection system to a PTK.

In one implementation of the present invention, the method comprises testing of a protective relay of the feeder under maintenance and transferring the feeder protection system from the PTK to the feeder protection relay followed by a trip test shut down of 5 minutes and putting back the feeder under maintenance on load.

Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.

BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS

The above and other aspects, features and advantages of the embodiments of the present disclosure will be more apparent in the following description taken in conjunction with the accompanying drawings, in which:

Figure 1 illustrates the schematic view of the Protection Transfer Kit (PTK) unit according to one of the embodiments of the present invention.

Figure 2 illustrates the flowchart of the methods of assembling and operation involved during the protective gear maintenance of the feeder using PTK according to one of the embodiments of the present invention.

Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may not have been drawn to scale. For example, the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure. Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of various embodiments of the present disclosure as defined by the claims and their equivalents. It includes various specific details to assist in that understanding, but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the various embodiments described herein can be made without departing from the scope and spirit of the present disclosure. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness.

The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the present disclosure. Accordingly, it should be apparent to those skilled in the art that the following description of various embodiments of the present disclosure is provided for illustration purpose only and not for the purpose of limiting the present disclosure as defined by the appended claims and their equivalents.

It is to be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, a reference to "a component surface" includes a reference to one or more of such surfaces.

All terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which various embodiments belong. Further, the meaning of terms or words used in the specification and the claims should not be limited to the literal or commonly employed sense, but should be construed in accordance with the spirit of the disclosure to most properly describe the present disclosure.

The terminology used herein is for the purpose of describing particular various embodiments only and is not intended to be limiting of various embodiments. As used herein, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising" used herein specify the presence of stated features, integers, steps, operations, members, components, and/or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, members, components, and/or groups thereof. Also, Expressions such as "at least one of," when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.

The present invention relates to a system for minimization of the shutdown period during the protective gear maintenance of a feeder. It discloses a Protection Transfer Kit (PTK) unit which significantly reduces the shutdown time from around sixty minutes to around five minutes only. This is done by way of transferring the ‘protection system’ of the feeder of the Power Distribution System under maintenance to the PTK. Further, in the present invention, the protection system of the feeder under maintenance is transferred to "PTK" and the existing protection system of the feeder is made free to carry out necessary maintenance activities that provide uninterrupted power supply to the consumers.

In on implementation of the present invention, there are provided numerical relays, Digital Meter for load display (e.g. secure make SATEC model), change-over system and necessary hard wirings required for transferring the ‘protection system’ of the feeder of the Power Distribution System under maintenance to the PTK. The Kit disclosed in the present invention is to be used for protective gear maintenance for the feeders, Bus Sections, or Bus Couplers in 6/11kV level where the load is radial or network changeover is not possible or avoidable.

Figure 2 of the present invention illustrates the flowchart of the methods of assembling and operation involved during the protective gear maintenance of the feeder using PTK in the present disclosure. It discloses a need for a thorough investigation and acknowledgment of the Protection System (PS) of the feeder e.g. CT ratio, relay settings, loads current, protection type, conditioning etc. for identifying that which maintenance to be done. Further, the Connections of wires to the PTK are done properly for Current Transformer (CT) and Control Circuits which is followed by a necessary measurement and monitoring step. After the step of monitoring and measurement, the changeover operation of protection to the Protection Transfer Kit. Further, the present invention discloses testing of the carry out the protective relay of the feeder under maintenance and then transferring the protection from PTK to the feeder protection relay followed by taking shut down of 5 minutes for the trip test. Once, all the above-mentioned methods are performed, the feeder under maintenance is put back to the service.

In one implementation of the present invention, a system for protection transfer for feeder maintenance in a power distribution system is disclosed which comprises a feeder of the power distribution system comprising a protection system, plurality of numerical relays, a current transformer, plurality of control circuits and a digital meter configured to display the load of the feeder.

In one implementation of the present invention, the system comprises a changeover system and plurality of hard wirings configured to transfer the protection system of the feeder of the power distribution system to a Protection Transfer Kit (PTK) during maintenance of the feeder.

In one implementation of the present invention, the protection system of the feeder is configured to identify the maintenance to be done in the feeder.

In one implementation of the present invention, a method of transferring protection for feeder maintenance in a power distribution system is disclosed and the said method comprises steps of identifying the maintenance to be done in a feeder, connecting wires to a PTK for a control transformer and plurality of control circuits, measuring and monitoring of feeder parameters and transferring of a feeder protection system to a PTK.

In one implementation of the present invention, the method comprises testing of a protective relay of the feeder under maintenance and transferring the feeder protection system from the PTK to the feeder protection relay followed by a trip test shut down of 5 minutes and putting back the feeder under maintenance on load.

Stages of Development:
Following are the stages of development of the present invention: Initially, in Stage 1, a Kit was developed and a trial was carried out on table top using two numbers of relays of different make e. g. electromechanical and numerical as a feeder protection relay. Necessary protection transfer is done to PTK and ensures correct change over. Operation repeatability was also checked.

In Stage 2, initially, the Kit was used during Protective gear maintenance of a less important 11kV feeder and subsequently used for other non-sheadable feeders also. Total working time for a feeder that was measured to be around 70 minutes. However, the actual shut down time was only around 5 minutes.

Those skilled in the art will recognize other use cases, improvements, and modifications to the embodiments of the present disclosure. All such improvements and other use-cases are considered within the scope of the concepts disclosed herein.
,CLAIMS:1. A system for protection transfer for feeder maintenance in a power distribution system, said system for protection transfer for feeder maintenance comprising:
a feeder of the power distribution system comprising a protection system;
plurality of numerical relays;
a current transformer;
plurality of control circuits;
a digital meter configured to display load of the feeder,
wherein the system comprises a changeover system and plurality of hard wirings configured to transfer the protection system of the feeder of the power distribution system to a Protection Transfer Kit (PTK) during maintenance of the feeder.

2. The system for protection transfer for feeder maintenance in a power distribution system as claimed in claim 1, wherein the protection system of the feeder is configured to identify the maintenance to be done in the feeder.

3. A method of transferring protection for feeder maintenance in a power distribution system, said method comprising:
identifying the maintenance to be done in a feeder;
connecting wires to a PTK for a control transformer and plurality of control circuits;
measuring and monitoring of feeder parameters;
transferring of a feeder protection system to a PTK;
wherein the method comprises testing of a protective relay of the feeder under maintenance and transferring the feeder protection system from the PTK to the feeder protection relay followed by a trip test shut down of 5 minutes and putting back the feeder under maintenance on load.