Description:TECHNICAL FIELD OF THE INVENTION
The present invention relates to road lighting management system. More particularly the invention relates to a smart street light management system which is pilfer sensitive and includes phase auto-changeover feature and protects the meters under adverse loading condition to ensure the revenue protection.

BACKGROUND OF THE INVENTION
Along with the development of technology of Internet of things, country is also more concrete to the construction requirements of smart city, and as the subsystem wisdom energy that smart city is built, the energy-conservation wisdom control and management carrying out street lamp is the concrete application of the wisdom energy.

Street lamp as the public infrastructure of city illumination, the important component part of not still urban construction and inseparable with daily life, the social security in city, traffic safety and city look and feel play immeasurable role. Meanwhile, whether the advanced person of road lamp management and control level, and direct reaction the height of urban modernization civilization degree. Along with the development of wireless communication technology, high automaticity, the Street Lamp Monitor System of highly reliable operation has become as the metropolitan important symbol of construction of modern.

In recent years, along with expanding economy and population increase on a large scale, energy shortage, environmental pollution become day by day serious, have caused the concern in the whole world. City illumination is as the important part of India's electric consumption on lighting, its energy consumption problem has increasingly been subject to the attention of country, development along with radio communication and information automation technology, traditional street lamp control system pattern has manifested drawback gradually, not only utilization rate of electrical is low, cause the profligacy of the energy, and way to manage falls behind, add artificial inspection and the trouble safeguarded.

Lighting energy saving, design are the sources, and the city illumination design should prevent the high brightness that covets, and over proof construction also will prevent not take into account lighting quality, reduce lighting criteria and go to implement energy-conservation. To take all factors into consideration the performance and the energy-saving effect of roadway lighting system in the design, get hold of each sport technique segments such as choose reasonable lighting system, light source, light fixture and auxiliary equipment, make the lighting energy saving effect reach maximization.

Almost the entire energy supply for street lighting purposes is catered through unmetered supplies since inception. The revenue collection in this sector use to take place through the billing against the number and wattage of lamps in use and the contractual burning hours as agreed upon. The Unmetered Street Lighting billing arrangement was prone to loss of revenue due to:

1) Unilateral change in number and rating of the lamps in use by the public bodies.
2) Unauthorized abstraction of electrical energy from the street lighting supplies for the purposes other than illumination of streets and public places.
3) The fixed wattage of ballast and choke widely varies from superior to inferior grade manufacturers in addition to the deterioration in the energy efficiency during their life cycle.
4) Stretched usage beyond contractual burning hours due to manual ON/OFF operation and/or failure of controlling contactors due to gross overloading (O/L).
5) Changeover to billing through meter was not agreeable due to the apprehension of negative impact on the financial interest of the public bodies.

There has thus been a need to develop an off the shelf metering system which will overcome the drawbacks of the conventional system with essential features for regulatory compliances, revenue protection & economic operation and maintenance expenses.

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 of the prior art.

An object of the present invention is to provide pilfer sensitive smart street light management system with auto phase changeover to protect the meters under adverse loading condition to ensure the revenue protection.

Another object of the present invention is to provide pilfer sensitive smart street light management system with auto phase changeover, which provides switching on and off the load at editable pre-set time.

Another object of the present invention is to provide pilfer sensitive smart street light management system with auto phase changeover, which provides self-protection against overloading.

Yet another object of the present invention is to provide pilfer sensitive smart street light management system with auto phase changeover with increased billing efficiency, elimination of manpower, and accurate billing.

Yet another object of the present invention is to provide pilfer sensitive smart street light management system with auto phase changeover, which provides access to the fault, load pattern, billing pattern, anomalies from remote and take action against it.

Yet another object of the present invention is to provide a pilfer sensitive smart street light management system with auto phase changeover, which eliminates the probability of stretched usage beyond contractual burning hours due to normal ON/OFF Operation and thus eliminating unnecessary electrical usage, which in turn reduces carbon foot-print.

Yet another object of the present invention is to provide a pilfer sensitive smart street light management system with auto phase changeover, which provides better reliability of street lighting supply during unavailability of one or two incoming system phases.

According to the present invention, there is provided a pilfer sensitive smart street light management system with auto phase changeover comprising an enclosure comprising at least one MCCB with thermal magnetic release adapted to sense and trip on short circuit and prolonged overload condition, at least one current transformer adapted for sensing metering, fault current and feeding it to a CT meter, at least one meter cum controller unit with a control circuit adapted to monitor protection of the CT meter against overload, plurality of latching relays, a relay controller adapted to control the latching relays, at least three MCBs adapted to protect the control circuit from internal short circuit wherein the system comprises plurality of power contactors and auxiliary contactors adapted to enable three phase to one phase auto changeover and the CT meter is adapted to switch ON and OFF the load at pre-set time. Further, the switching ON/OFF timings of the units is pre-set and configurable from remote.

In one implementation of the present invention, the system uses Inverse Definite Minimum Time Lag (IDMTL) relay logic for overload prevention and the system comprises a remote base station adapted to monitor the system.

In one implementation of the present invention, the system comprises a GSM based communication modem adapted to retrieve the system data through GSM network for data analysis.

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 Shows the schematic diagram of Pilfer sensitive smart street light management system (SSLMS) with auto-changeover feature, according to one of the embodiments of the present invention.

Figure 2 Shows the schematic view of the in-house developed 3-phase to 1-phase convertor for continuous supply, according to one of the embodiments of the present invention.

Figure 3 Shows the Schematic Diagram of pilfer Sensitive Smart Street Light management System with Phase Auto-Changeover Feature – General Overview, according to one of the embodiments of the present invention.

Figure 4 Shows the Schematic Diagram of pilfer Sensitive Smart Street Light management System with Phase Auto-Changeover Feature – power panel outside, according to one of the embodiments of the present invention.

Figure 5 Shows the Schematic Diagram of pilfer Sensitive Smart Street Light management System with Phase Auto-Changeover Feature – Meter panel outside, according to one of the embodiments of the present invention.

Figure 6 Schematic Diagram of pilfer Sensitive Smart Street Light management System with Phase Auto-Changeover Feature – Meter panel inside, according to one of the embodiments of the present invention.

Figure 7 Schematic Diagram of pilfer Sensitive Smart Street Light management System with Phase Auto-Changeover Feature – Power panel inside, 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 purposes only and not for the purpose to limit the present disclosure as defined by the appended claims and their equivalents.

The present invention provides pilfer sensitive smart street light management system with auto phase changeover to protect the meters under adverse loading condition. The present disclosure provides proper registration of energy, switching on & off the load at editable pre-set time, self-protection against O/L, AMR/AMI through Base-Station server for energy bills, condition monitoring of the unit and switching devices and generation of MIS reports for initiating operation and maintenance action.

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 disclosure will now be described more fully with reference to the accompanying drawings, in which various embodiments of the present disclosure are shown. The present disclosure may, however, be embodied in many different forms and should not be construed as being limited to the various embodiments set forth herein, rather, these various embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the present disclosure. Furthermore, a detailed description of other parts will not be provided not to make the present disclosure unclear. Like reference numerals in the drawings refer to like elements throughout.

The present invention provides pilfer sensitive smart street light management system with auto phase changeover to protect the meters under adverse loading condition to ensure the revenue protection. In the invention there is provided a pilfer sensitive smart street light management system with auto phase changeover comprising an enclosure comprising at least one MCCB with thermal magnetic release adapted to sense and trip on short circuit and prolonged overload condition, at least one current transformer adapted for sensing metering, fault current and feeding it to a CT meter, at least one meter cum controller unit with a control circuit adapted to monitor protection of the CT meter against overload, plurality of latching relays, a relay controller adapted to control the latching relays , at least three MCBs adapted to protect the control circuit from internal short circuit wherein the system comprises plurality of power contactors and auxiliary contactors adapted to enable three phase to one phase auto changeover and the CT meter is adapted to switch ON and OFF the load at pre-set time. Further, the switching ON/OFF timings of the units is pre-set and configurable from remote.

In one implementation of the present invention, the system uses Inverse Definite Minimum Time Lag (IDMTL) relay logic for overload prevention and the system comprises a remote base station adapted to monitor the system.

In one implementation of the present invention, the system comprises a GSM based communication modem adapted to retrieve the system data through GSM network for data analysis.

In the present disclosure the MCCB with thermal magnetic release is used to protect the unit from short circuit. The in-built intelligent overload tripping logic of the meter cum controller unit monitors the protection of the meter against O/L. The unit would switch off the load in case of sustained overloads beyond preset time based on the heating Time Constant of the units derived from the heating curves. The load will again be reclosed on elapse of the preset time again based on the cooling Time Constant of the unit derived from the cooling curve. In general, more the overload, the unit will remain switched off for a longer time to allow time for sufficient cooling of the service cables and other current carrying components of SSLMS unit. CTs are used to eliminate meter terminal burning due to excessive O/L and bad termination of the primary circuit.

The 3-Ø to 1-Ø changeover feature is unique and the street lighting luminaries catered from one phase of any three phase service continue to be in operation even if only one phase is healthy as the street lighting load is automatically transferred to a healthy phase and provides better service to the consumers. This changeover facility is achieved thorough an innovative circuitry developed in-house using auxiliary contactors as shown in figure-2. The basic theory behind this architecture is that, in 3 Phase system peak value of every phase is 120 degrees apart, which is 6.7 mS apart, whereas 230 V auxiliary contactor switching time is much lesser than this, so at any instant of time only one phase peak value will be sufficient enough to actuate the contactor. The NO-NC arrangement make sure that at the same instant other two phases will be kept off to prevent from phase to phase short circuit.
Based on the requirements, the applicant has developed and designed different models to cater the differently loaded Street lighting supply catered through cable 25 sq. mm cable size to 70 sq. mm XLPE insulated aluminum conductor cable size. The varieties are based on specific type of loading, additional requirements like customer benefit, pilferage sensitivity etc.

The regulatory compliance and non-availability of any off-the shelf product with required features, prompted the applicants to install fully-customized units using smart CT meters with external switching for automatic remote ON/OFF and O/L prevention based on the IDMTL relay logic, Energy Audit Meter etc.

The Unit enclosure itself is in house designed and consists of mild steel enclosure of around 16 SWG sheet thickness with powder painting to sustain hazard arising out of environmental exposure. Properly sealed MS enclosures of all the above models are capable of arresting pilferage from the open service cut outs of the erstwhile unmetered street lighting services. The operating signal for the switching devices are provided by the meter cum controlling unit either directly or through the intermediate controller unit through its RJ port.

For Supervisory control and remote data acquisition one Base-Station program and various screens have been developed with the help of vendor in association with the logic given by the applicant.

The following MIS reports can be generated on demand.
I. Meter Installation.
II. AMR Performance.
III. Consumption Pattern.
IV. Condition Monitoring.
V. Relay Operation.

Major effort on selection of switching device to ensure uninterrupted supplies and nominal wattage requirement in the “ON” condition (i.e. for 12 hours of the night) resulted in introduction of Latching Relay (a bi-stable device), which was a marked success in the field trial. Compatibility of the switching devices (Contactors & Latching Relays) with the meter-cum-controller gradually matured through site feedbacks and troubleshooting. The switching ON/OFF timings of the units are pre-set and is configurable from remote. The units normally switch on at dusk and switch off at dawn. This timing can be changed individually or in a batch, based on user requirement from in house developed HES (Head End System).

Further, suitably designed protective cover has been provided for covering the apertures for MCCB operating lever, Push Button, Meter Viewing polycarbonate sheet to prevent dust ingression thereby making its internal components protected from hazardous site conditions. In this disclosure, great thrust was put on for maximum utilization of the available space at various planes to make the size of the unit as small as possible to make suitable to be fitted inside existing kiosks of the public bodies and also leave space for the consumer’s main switches/cut outs in the same kiosks. The use of latching relays ensures negligible power consumption as the latching relay uses practically no power in operation except during the change of state.

In the present disclosure the supply during day time for maintenance can be derived through a local push button as well as from remote base station. This feature provides supply during day time for a pre-defined configurable time for carrying out maintenance activities by the public bodies. Three 10 Amps MCBs are used in the control panel to provide protection to the modem and the control circuitry.

The system can be monitored through remote Base Station very effectively. Various parameter settings like overload parameter setting, seasonal setting, and maintenance ON (during daytime) can be carried out from remote. Data from the units can also be retrieved through GSM network for necessary data analysis. Faults on the incoming cable can be identified from remote which provides great benefit to the industry. Billing is automatic and requires minimal human intervention.

Stages of development:
As the installation commenced, various site feedbacks were captured, each and every failure were analyzed and the outcome of the analysis were passed on to the manufacturer for corrective measures at their end.

In-house modifications incorporated based on the site feedback and selection of the type of controller, current rating of the Latching Relay resulted into the present day units which are mostly trouble free.

However, analysis of the breakdowns indicated a few areas wherein repeated breakdowns were taking place.

(a) Failure of the meters while used with power contactors as switching device. The data collected from the field revealed that the meters failed due to jamming of the contactors’ plungers. Further investigation revealed that the contactor coils used were of 230 volts rating with operating tolerance from 80% to 110% of the rated voltage, i.e. permitted operating voltage band of 184 to 253volts. As distribution licensee we maintain voltage within +/-9% of the declared voltage for LV & MV network i.e. between 209.3 to 250.7 volts but for reasons beyond control this limits are crossed in reality during lean hours of night.

A field monitoring unit and analyzer was fitted and the incoming supply voltage was studied for 24 hrs. at sites wherein repeated coil failures took place, which revealed that during the lean period the supply voltage increased significantly and crossed the upper threshold limits, causing overheating of the coil thereby melting of the bobbin of the coil, finally resulting into jamming of the coil plunger. It was decided to procure coil of higher rated voltage (240v) to minimize the coil vis-à-vis meter failures as the upper withstand limit of the coil is enhanced to 264 volts.

The MOSFET used in the meter had a max. current carrying capacity of 150mA. The contactors used had a closing VA of 64 (i.e. closing current of 64/230 = 278 mA) and VA required in closed condition is 5.4.

During closing operation, the current through the MOSFET exceeded its capacity but for a fraction of a second (i.e. closing time). In case of plunger jamming this high current would continuously flow through the MOSFET as the plunger is obstructed to reach the closed position. This led to the burning out of the MOSFETs.

The higher rating MOSFET used in the meter, which would be able to handle the full VA of the contactor coils for indefinite period.

In addition, an auxiliary relay has been introduced for operating the contactor coil thereby isolating the meter MOSFET. These changes were implemented and the breakdown rates have dropped drastically.

(b) 230V and 400V 3 Ph. To 1 Ph. Circuit - Due to discontinuity of the system neutral the 3Ø to 1Ø changeover system using auxiliary contactors of 230 volt coils starts chattering till the auxiliary contactors tip burns resulting into flickering of the street lights to start with and final interruption. Since the failure of the neutral in the distribution network is unavoidable, it was decided to design a changeover system with 400 volt contactor coils to solve the problem. The new design was successful in field trial. The design will require at least two phases for its operation. Both of the types are operational but the 230V circuit is more in number because of better reliability, because of it can be operational, even if only one phase is available.

Some of the non-limiting advantages of the present invention are as follows:

• Automatic On/Off timing eliminates the manual labour of switching on and off the supply during dawn and dusk, for which consumer gets automatic street light illumination at night.
• Intelligent O/L and S/C tripping makes sure that any pedestrian does not gets electrocuted due to short and body earthing of the network.
• In house developed automatic 3 phase to 1 Phase changeover circuit enables consumer to enjoy more reliable supply during one/two phase supply off.
• Due to elimination of manual intervention to On/Off the supply circuit, the Electricity consumption will only be in the nigh time, when it is actually required and not in the day time, which in turn reduces the unnecessary electricity consumption and hence less carbon footprint.
• In addition to the regulatory compliance, the billing is done on actual consumption basis, which in turn enhances the sale figure in electricity consumption.
• As the meter can be read from remote, so manpower involvement for meter reading is down to zero and the billing efficiency is also increased.

The overload tripping characteristics as detailed in table-1have been arrived at through the in-house temperature rise test of the unit. The heating and cooling time constants have been estimated from heating and cooling curves drawn during the heat-run test. A sample heating and cooling curve along with the relevant test results obtained during the test carried out at the laboratory of CESC Ltd. is mentioned in table-2 as a ready reference below.

TABLE-1:OVERLOAD TRIPPING LOGIC OF 1 PHASE METERING SYSTEM

Sl. No Overloading % Effect on Switch
1 Up to 125% of Pre-set Base Current Overloading permissible with no tripping action.

2 >125% &<=130% of Pre-set Base Current If overloading persists for 30 minutes, then unit will trip and remain switched off for 30 minutes before auto reclosing.

3 >130% &<=140% of Pre-set Base Current If overloading persists for 15 minutes, then unit will trip and remain switched off for 45 minutes before auto reclosing.

4 >140% &<=150% of Pre-set Base Current If overloading persists for 15 minutes, then unit will trip and remain switched off for 60 minutes before auto reclosing.

5 >150% of Pre-set Base Current On sensing overloading, unit will trip instantaneously and will remain switched off for 2 hours before Auto Reclosing.
OVERLOAD TRIPPING LOGIC OF 3 PHASE METERING SYSTEM

Sl. No Overloading % Phase Effect on Switch
1 Up to 125% of Pre-set Base Current Simultaneous on all 3 Phases Overloading permissible with no tripping action

2
>125% &<=130% of Pre-set Base Current
Any 1 or 2 Phases If overloading persists for 30 minutes, then respective phase will trip and remain switched off for 30 minutes before auto reclosing.

3
>125% &<=130% of Pre-set Base Current

Simultaneous on all 3 Phases If overloading persists for 15 minutes, then any one phase will trip followed by othersat a regular interval of 15 minutes. Each of the phases will auto reclose after elapse of 20 minutes from the time of switching off.

4
>130% &<=140% of Pre-set Base Current
Any 1 or 2 Phases If overloading persists for 15 minutes, then respective phase will trip and remain switched off for 45 minutes before auto reclosing.

5
>130% &<=140% of Pre-set Base Current

Simultaneous on all 3 Phases If overloading persists for 15 minutes, then any one phase will trip followed by othersat a regular interval of 15 minutes. Each of the phases will auto reclose after elapse of 30 minutes from the time of switching off.

6
>140% &<=150% of Pre-set Base Current
On any or all Phases If overloading persists for 15 minutes, then respective phase will trip and remain switched off for 60 minutes before auto reclosing.

7
>150% of Pre-set Base Current
On any or all Phases If overloading is sensed, then respective phase will trip immediately and remain switched off for 120 minutes before auto reclosing.

(TABLE: 2)

In view of the present disclosure which describes the present invention, all changes, modifications and variations within the meaning and range of equivalency are considered within the scope and spirit of the invention. It is to be understood that the aspects and embodiment of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiment may be combined together to form a further embodiment of the disclosure.

Claims:1. A pilfer sensitive smart street light management system with auto phase changeover, said system comprising:
an enclosure comprising:
at least one MCCB with thermal magnetic release adapted to sense and trip on short circuit and prolonged overload condition;
at least one current transformer adapted for sensing metering, fault current and feeding it to a CT meter;
at least one meter cum controller unit with a control circuit adapted to monitor protection of the CT meter against overload;
plurality of latching relays;
a relay controller adapted to control the latching relays;
at least three MCBs adapted to protect the control circuit from internal short circuit;
wherein the system comprises plurality of power contactors and auxiliary contactors adapted to enable three phase to one phase auto changeover; and
the CT meter is adapted to switch ON and OFF the load at pre-set time;
wherein the switching ON/OFF timings of the units are pre-set and configurable from remote.

2. The system as claimed in claim 1, wherein the system adapted to adopt Inverse Definite Minimum Time Lag (IDMTL) relay logic for overload prevention through the main MCCB.

3. The system as claimed in claim 1, wherein the smart meter is adapted to switch off the load through latching relay, in case of sustained overloads beyond preset time based on the heating Time Constant of the units derived from the heating curves.

4. The system as claimed in claim 1, wherein the smart meter Is adapted to switch on the load through latching relay, on elapse of the preset time based on the cooling Time Constant of the unit derived from the cooling curve.

5. The system as claimed in claim 1, further comprising a remote base station adapted to monitor the system.

6. The system as claimed in claim 1, further comprising a GSM based communication modem adapted to retrieve the system data through GSM network for data analysis.

7. The system as claimed in claim 1, wherein supply during day time for maintenance is derivable through a local Push Button or from the remote Base Station.

8. The system as claimed in claim 1, further comprising at least one Base-Station program and plurality of screens adapted to provide supervisory control and remote data acquisition.

9. The system as claimed in claim 1, wherein at least one meter cum controller unit comprises a RJ port adapted to provide operating signal for switching devices.

10. The system as claimed in claim 1, wherein the enclosure is made up of Mild Steel (MS).