WO2020060390A1

WO2020060390A1 - Method of detecting faulty streetlamp and system thereof

Info

Publication number: WO2020060390A1
Application number: PCT/MY2019/050063
Authority: WO
Inventors: Afdzal Syahadat Husni Bin HUSIN; Dr. Roslee Bin MOHD SABRI; Muhammad Syargawi Bin ABDULLAH; Mohamad Faisal Bin JAAFAR NG; Wan Mohd Khidhir Bin ABDUL AZIZ
Original assignee: Mimos Bhd
Current assignee: Mimos Bhd
Priority date: 2018-09-21
Filing date: 2019-09-20
Publication date: 2020-03-26
Anticipated expiration: 2021-03-21
Also published as: MY190940A

Abstract

The present invention relates to method (100) of detecting at least one faulty streetlamp, comprising steps of calibrating a monitoring apparatus (10) connected in series to a plurality of streetlamps and a power supply, performing on-site training for the monitoring apparatus (10) connected in series to the plurality of streetlamps and the power supply, monitoring the plurality of streetlamps using the monitoring apparatus (10), normalizing the real-time current (150), determining at least one faulty streetlamp (160) by comparing normalized current with ideal current, and at least one streetlamp is determined faulty (163) if the normalized current is less than the ideal current The present invention also relates to a system (200) for detecting at least one faulty streetlamp comprises a monitoring apparatus (10) connected in series between the plurality of streetlamps and the power supply, a server (20), a configuration station (30) and a monitoring station (40).

Description

METHOD OF DETECTING FAULTY STREETLAMP AND SYSTEM THEREOF

FIELD OF INVENTION

This invention relates to a method of detecting faulty streetlamp and a system thereof, and more particularly to a method and system for monitoring a plurality of streetlamps connected in series to a common power supply and detecting at least one faulty streetlamp from the plurality of streetlamps, BACKGROUND OF THE INVENTION

Streetlamps are installed for lighting roadsides or public areas to prevent traffic accidents and crimes. Generally, a plurality of streetlamps is connected in a loop and powered by a common power supply controlled by a photoelectric controller that automatically turns on the streetlamps at night and turns off the streetlamps at dawn. The power supply and the photoelectric controller are usually housed within a single distribution box.

For safety reasons and effective operation, a failure of at least one streetlamp should be detected at the soonest possible. Conventionally, streetlamp fault detection is performed by maintenance personnel at regular intervals by manually inspecting each streetlamp while the streetlamps are still operating. However, due to large number of streetlamps, manual inspection is a very time and labour consuming, which makes it difficult to find the fault in a timely manner. In addition, the streetlamp may fail shortly after the inspection is performed or only fail temporarily during specific operating condition which is hard to detect during routine inspection. If the failed streetlamp is not repaired at the soonest possible timely manner, traffic and safety problems are likely to arise.

One way to detect faulty streetlamp in timely manner is to install a sensor on each streetlamp to monitor the streetlamp and send information on the streetlamp’s state to a remote station in real-time via wired or wireless networking technology. However, installation of the sensors and communication modules on every streetlamp is both difficult and cosily . Another way to detect the faulty streetlamp suggested by the prior art is by monitoring electric current drawn by the plurality of streetlamps. Typically, the plurality of streetlamps is connected in a loop to a common power supply supplying alternating current (AC) supply voltages. If all of the streetlamps are operating normally, then the streetlamps should draw a maximum current from the supply voltages. By measuring amount of current drawn by the streetlamps in real-time, one can deduce that at least one streetlamp is faulty if the current drawn is less than the expected maximum current. However, in a real situation, the AC supply voltage usually fluctuates between certain operating margins. As a result, total current drawn by the plurality of streetlamps also changes accordingly, which means the maximum current drawn can take on several values depending on value of the supply voltages. The use of expected maximum value of current in the prior art also assumes that all the streetlamps have the same physical and electrical characteristics. However, in practice, this is not the case since the streetlamps come In various shapes, sizes, technologies and brands. Even if the streetlamps used in the field are the same as the ones used during calibration setup, their current consumptions might still differ due to aging, installations and environmental factors. Due to this, the expected maximum current and the current drawn in real-time could still differ, thus triggering false alarm even though all streetlamps are operating normally.

A prior art of patent application WO 02/067637 A1 (‘637) discioses a system and method of managing road lights including detecting faulty lamp unit. The system in‘637 comprises of two unit lamps, a switching circuit between the two unit lamps and a detector. The detector compares current passing through a first lamp unit at a predetermined time during a voltage cycle and consequently outputs a failure signal when the detected current deviates from predetermined parameters. However,‘637 does not consider fluctuating supply voltage through the lamp unit which may cause various outputs current detected by the detector.

Another prior art of patent US 9258872 B2 (‘872) discloses a system and method to detect faulty streetlamp by implementing an impedance condition table to detect the faulty streetlamp from a streetlamp loop. A streetlamp fault detection apparatus is used to measure a total impedance value of the streetlamp loop to detect a faulty streetlamp. The streetlamp loop is determined to be in a normal operating state if the total impedance value stably falls within the reference impedance range in a measurement period, and determines that the streetlamp loop is in a fault state if the total impedance value falls into the non-reference impedance range in the measurement period.

The prior arts however insufficiently address the problems of detecting faulty streetlamp by not considering the fluctuating supply voltage and consequently._, there exists a need to provide a system and method to monitor the plurality of street!amps to detect faulty streetlamp in real-time. Accordingly, It is important to provide a system and method that can remotely monitor the plurality of streetlamps and detect faulty streetlamp from the plurality of streetlamps connected to a common AC supply voltage.

SUMMARY OF INVENTION

The following 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 invention its sole purpose is to present some concepts of the invention in a simplified form as a prelude to the more detailed description that is presented later.

It is an objective of the present invention to provide a method and system of monitoring a plurality of streetlamps connected in series to a power supply to defect at least one faulty streetlamp from the plurality of streetlamps.

If is also an objective of the present invention to provide a method of normalizing real-time current before determining at least one faulty streetlamp.

According to the present invention, there is provided a method of detecting at ieasf one faulty sireetiamp, characterized by the steps of deriving calibration coefficient and calculating ideal current by calibrating a monitoring apparatus connected in series to a plurality of streetlamps and a power supply, calculating correction factors by performing on-site training for the monitoring apparatus connected in series to the plurality of streetlamps and the power supply, measuring real-time current for monitoring the plurality of streetlamps using the monitoring apparatus and sending to a server, normalizing the real-time current by a processor at the server to obtain normalized current by multiplying the real-time current with the correction factors and determining at least one faulty streetlamp by comparing the normalized current with the ideal current by the processor, wherein at least one streetlamp is determined faulty if the normalized current is less than the ideal current. in a preferred embodiment of the invention, the step of deriving calibration coefficient and calculating ideal current by calibrating a monitoring apparatus connected in series to a plurality of streetlamps and a power supply further comprising steps of measuring a plurality of currents drawn by the plurality of streetlamps operating normally powered by variable calibration voltages, wherein the variable calibration voltages starts from a minimum supply voltage and is increased with a predetermined voltage difference until a maximum supply voltage for each current measurement, and wherein the plurality of streetlamps is turned on gradually for each calibration voltage. The step also further comprise of modelling a number of streetlamps and the current measurements for each calibration voltage into polynomial factor, deriving calibration coefficient for each calibration voltage from the polynomial factor, calculating a plurality of ideal currents drawn by the plurality of streetlamps for the variable calibration voltages by multiplying the calibration coefficient for each calibration voltage with a particular number of streetlamps for all the variable calibration voltages and configuring the calibration coefficients and the plurality of ideal current into the server. in a preferred embodiment of the invention, the step of calculating correction factors by performing on-site training for the monitoring apparatus connected in series to the plurality of streetlamps and the power supply comprising steps of receiving a plurality of supply voltages and currents drawn by the plurality of streetlamps operating normally, measured by the monitoring apparatus, identifying a minimum and maximum supply voltages from the plurality of supply voltages measured by the monitoring apparatus_* creating groups of voltages by dividing the difference between the maximum and the minimum value of the supply voltages with a predetermined voltage difference, wherein each group represents a range of supply voltage, grouping the plurality of measured currents according to the measured supply voltage into the corresponding groups of voltages, computing an actual current for each group of voltages by calculating average current in each group of voltages, calculating correction factor for each group of voltages by dividing the ideal current with the actual current and configuring the correction factors into the server.

In a preferred embodiment of the invention, value of the correction factors for normalizing the real-time current is chosen based on the group of voltages. In a preferred embodiment of the invention, the method further comprising a step of determining a faulty monitoring apparatus by monitoring time interval for the server receiving the reai-time current from the monitoring apparatus, wherein the monitoring apparatus Is determined faulty if the time interval is greater than a pre-determined time threshold.

According to the present invention, there is also provided a system for detecting at least one faulty streetlamp comprising a monitoring apparatus comprising sensors connected in series between a plurality of streeflamps and a power supply to measure voltage and current drawn by the plurality of street!amps, a server comprising a processor to receive measured voltage and current from the monitoring apparatus, a configuration station to configure parameters for the monitoring apparatus and the server and a monitoring station to receive alert from the server, the processor of the sen/er configured to derive calibration coefficients and calculate ideal current drawn by the plurality of streetlamps operating normally, calculate correction factors and normalize real time current measured by the monitoring apparatus, determine at least one faulty streetlamp by comparing the ideal current with normalized current and determine if the monitoring apparatus is faulty.

In a preferred embodiment of the invention, the monitoring apparatus further comprising a transmitter to transmit the voltage and current to the server via a communication network. in a preferred embodiment of the invention, the monitoring apparatus is seif-reconfigurab!e via the configuration station if the transmitter fails to transmit the real-time current to the server within a pre-determined time interval.

In a preferred embodiment of the invention, the parameters further comprising a rate to measure the real-time current by the sensors, a retry count numbers to transmit the real-time current to the server via the communication network, settings of the server, and setting of the communication network. BRIEF DESCRIPTION OF THE DRAWINGS

The features of the invention will be more readily understood and appreciated from the following detailed description when read in conjunction with the accompanying drawings of the preferred embodiment of the present invention

Fig. 1 is a flow chart representing a method for detecting at least one faulty streetlamp in accordance to the present invention.

Fig 2 is a flow chart representing steps of calibrating a monitoring apparatus in accordance to the present invention.

Fig. 3 is a flow chart representing steps of performing on-site training for the monitoring apparatus in accordance to the present invention. Fig. 4 is a flow chart representing further detailed steps of determining at least one faulty streetlamp and determining faulty monitoring apparatus in accordance to the present invention.

Fig. 5 is a diagram illustrating general architecture of a system for detecting at least one faulty streetlamp in accordance to the present invention.

Fig. 6 is a flow chart representing steps of self-configuring the monitoring apparatus in accordance to the present invention.

DESCRIPTION OF THE PREFERRED EWIBODIN!ENT

The above mentioned features and objectives of this invention will become more apparent and better understood by reference to the following detailed description. It should be understood that the detailed description made known below is not intended to be exhaustive or limit the invention to the precise disclosed form, as the invention may assume various alternative forms. On the contrary, the detailed description covers all the relevant modifications and aiterations made to the present invention, unless the claims expressly state otherwise. The present invention discloses a method (100) of detecting at least one faulty streetiamp and a system (200) thereof. Typically, the plurality of sfreetlamps is connected in series to a common power supply supplying alternating current (AC) supply voltages^ Thus, the plurality of streetlamps represents a load to the power supply that draws a maximum current if all of the streetlamps are operating normally. If the current drawn by the plurality of streetlamps measured in real-time is less than the maximum current that should be drawn by the plurality of streetlamps operating normally, then it can be deduced that at least one streetiamp is faulty. The maximum current drawn by the plurality of streetlamps operating normally is hereby termed as an ideal current. The ideal current is calculated using calibration coefficient by considering variable supply voltage values. In the present invention, correction factors are used to normalize real-time current before comparison is made with the ideal current.

Referring to Fig.1 , the present invention provides the method (100) detecting at least one faulty streetiamp. In a preferred embodiment, the method (100) begins by the step of calibrating a monitoring apparatus (10) connected in series to the plurality of streetlamps and a power supply to measure voltages and currents drawn by the plurality of streetlamps. From the calibration, calibration coefficient is derived from polynomial factor modelled on the measured voltages and currents. Then, calibration coefficient and number of streetlamps at a supply voltage of interest are used to calculate the ideal current (110). On-site training is further performed by connecting the monitoring apparatus (10) in series to the plurality of streetlamps and the power supply at site to calculate correction factors (120), where the correction factors are later used for normalizing real-time current.

Steps of monitoring the streetlamps in operation is initiated by measuring real-time current drawn by the plurality of streetlamps (130) using the monitoring apparatus (10) and is sent to the server (20). Time interval of the server (20) receiving the real-time current is monitored (140) by the server (20) to determine if the monitoring apparatus (10) is faulty. If the monitoring apparatus (10) is detected faulty, a monitoring station (40) is alerted for further maintenance action. Otherwise, a processor at the server (20) normalizes the real-time current (150) to acquire normalized current by multiplying the real-time current with the correction factors. The processor compares the real-time current with the ideal current to determine if at least one streetiamp is faulty (160). Upon detecting at least one faulty streetiamp, the monitoring station (40) is alerted (180) by the server (20) for further maintenance action. The monitoring steps are repeated after a specified time interval upon alerting the monitoring station (40). If there is no faulty street!amp detected, then the monitoring steps continue by measuring the real-time data (150).

Fig. 2 illustrates the step of calibrating the monitoring apparatus (10) to derive calibration coefficient and calculate the ideal current (110) drawn by the plurality of streetlamps. In a preferred embodiment, calibration setup for calibrating the monitoring apparatus (10) comprises of the monitoring apparatus (10) connected in series to the plurality of streetlamps operating normally and is powered by a power supply source with variable supply voltages hereinafter known as variable calibration voltages. The step of performing calibration (110) begins by measuring a plurality of currents drawn by the plurality of streetlamps (111 ) severally. In the preferred embodiment, the variable calibration voltages starts from a minimum supply voltage and is increased with a predetermined voltage difference until a maximum supply voltage for each current measurement. Therefore, the calibration voltage starts with a minimum calibration voltage until a maximum calibration voltage. The current measurement is then repeated with the plurality of streetlamps turned on gradually for each calibration voltage. In one embodiment, the current measurement starts with the minimum calibration voltage while all the streetlamps are in off state. Then, the streetlamp is consecutively switches on one at a time to measure the corresponding current drawn until all the streetlamps are switched on. The current measurements are repeated by increasing the minimum calibration voltage with the predetermined voltage difference for each current measurement until reaching the maximum calibration voltage.

Then, a number of streetlamps and the currents measurements for each calibration voltage is modelled into polynomial factor (1 12). In the preferred embodiment, the number of streetlamps versus the current measurements at each calibration voltage is modelled by applying a curve-fitting function with a suitable polynomial to minimize mean squared error. The polynomial could be a linear or quadratic or cubic and so on. For each graph, calibration coefficient for each calibration voltage from the polynomial factor is derived (113) to generate a plurality of calibration coefficients for the variable supply voltages A plurality of ideal currents drawn by the plurality of streetlamp for the variable calibration voltages (1 14) is then calculated by multiplying the calibration coefficient for each calibration voltage with a particular number of streetlamps for all the variable calibration voltages. For example, the ideal current drawn by the plurality of streetlamps for each calibration voltage Is calculated by multiplying the calibration coefficient of a specified calibration voltage value with a particular number of streetiamps. Both the ideal current and calibration coefficient are configured (1 15) in a server (20) for reference during monitoring.

In an embodiment, the calibration coefficient is preferably chosen according to real-time voltage measured by the monitoring apparatus (10) if the measured real-time voltage is within range of the calibration voltages if the measured real-time voltage is less than the minimum calibration voltage, the calibration coefficient of the minimum calibration voltage is chosen. Otherwise if the real-time voltage is greater than the maximum calibration voltage, the calibration coefficient of the maximum calibration voltage is chosen.

The ideal current is calculated using the calibration coefficients at the specified calibration voltage assuming the streetiamps used during the calibration and those deployed on the roadside have the same physical and electrical characteristics. However, due to the plurality of streetiamps comes in various shapes, sizes, technologies and brands, the streetiamps used on-site may not be similar to the ones used during the calibration besides the street!amp may experience aging due to installation and environmental factors. Therefore, the idea! current drawn calculated and current measured in real-time could still differ above a predetermined threshold.

Fig. 3 illustrates the step of calculating correction factors (120) for normalizing the real-time data. Said step (120) begins by receiving variable supply voltages and currents drawn by the plurality of streetiamps operating normally (121 ), wherein the variable supply voltages and currents are measured by the monitoring apparatus (10) during the calibration (110). In the preferred embodiment, the variable supply voltages are measured in real-time and recorded for a period of time to capture all possible variations of the supply voltages and the corresponding currents drawn due to the variable supply voltages. Each measurement of the variable supply voltages is rounded to nearest integer.

From the variable supply voltages, minimum and maximum supply voltages are identified (122). A number of groups of voltages are created (123) by dividing the difference between the maximum and minimum supply voltages with the predetermined voltage difference, Therefore, each group represents a range of supply voltage with equal difference. Measurements of the current drawn during step {121 } are grouped (124) into corresponding group of voltages based on the supply voltages measured by the monitoring apparatus (10). An actual current is computed (125) for each group of voltages by finding average current in each group of voltages. The correction factor is calculated (126) for each group of voltages by dividing the ideal current with the actual current. In another embodiment, the correction factor can also be calculated (128) by dividing the actual current with the ideal current. There is no specific condition to decide one over the other. However, if one technique (i.e. dividing the ideal current with the actual current or vice versa) is preferred or used, said technique is to be used throughout the whole method (100). For the groups of voltages without real-time current values, 1 is assigned as their correction factors The correction factors are also configured into the server (20) (127). in a preferred embodiment, value of the correction factor for the step of normalizing the real-time current (150) is chosen based on the group of voltages corresponding to the real-time current. This means the correction factor is chosen according to received voltage measurement if the real-time voltage is within the range of the group of voltages li the real-time voltage is less than the minimum calibration voltage, the correction factor of the minimum calibration voltage is chosen, else if the real-time voltage is greater than the maximum calibration voltage, the correction factor of the maximum calibration voltage is chosen.

Reference is ROW made to Fig. 4 illustrating further detailed steps of determining faulty monitoring apparatus (10) and determining at least one faulty street!amp in accordance to the present invention (101 ). Periodically (10), the server (20) monitors the time interval (103) of receiving the real-time current (102) from the monitoring apparatus (10). if the time interval of receiving the real-time current is greater than a predetermined time threshold, the monitoring apparatus (10) is determined faulty (107) and monitoring station (40) is alerted (108) for further maintenance action in one embodiment, the server (20) performs periodic checking on timestamp of the latest current measurements received from the monitoring apparatus (10) to determine if the real-time current is stale i.e. the latest measurements received from the monitoring apparatus (10) are older than a specified time period. If staleness is detected, this indicates that the monitoring apparatus (10) is not operating normally and the server (20) notifies the monitoring station (40) via wired or wireless networking technology. Otherwise, the processor at the server (20) normalizes the real-time current (104) to acquire the normalized current. The processor compares the normalized current with the ideal current (105). At least one street!amp is determined faulty (108) if the current is less than the ideal current. The monitoring station (40) is alerted (108) to inform that at least one streeiiamp is faulty for further maintenance action and the server (20) continue to receive the real time current (102) after a specified time interval. If the normalized current is equal to the ideal current, the server (20) continues to receive the real-time current (102) from the monitoring apparatus (10). Referring to Fig. 5 is the system (200) for monitoring a plurality of streetlamps to detect at least one faulty streeiiamp in accordance to the present invention. The system (200) comprising the monitoring apparatus (10) connected in series between a distribution box (5) and the plurality of streetlamps, a configuration station (30), the server (20) and the monitoring station (40). In a preferred embodiment, the distribution box (5) housing power supply to the plurality of streetlamps. In another embodiment, the monitoring apparatus (10) may be positioned in the distribution box (5) to monitor and measure the supply voltage and current drawn at a predetermined time interval. The server (20) is preferably a cloud based server. The monitoring apparatus (10) comprises sensors to measure voltages and currents drawn by the plurality of streetlamps. The monitoring apparatus (10) also comprises a controller operatively coupled to the sensors to receive the voltage and current from the sensors. A software routine coupled to the controller to define the monitoring apparatus (10) behaviour wherein the supply voltage comprises a function to initialize the monitoring apparatus (10) and read parameters upon reset, a function to periodically wake up a processor in the monitoring apparatus (10), a function to measure the current and voltage from the sensors and transmit the real-time current to the server (20) and a function to communicate with the configuration station (30) to configure the controllers parameters. in a preferred embodiment, the monitoring apparatus (10) further comprising a transmitter to transmit the reai-fifne data to the server (20) via a communication network. The communication network may comprise of wired or wireless networking technology. The monitoring apparatus (10) further comprises an interface connecting either through wired or wireless, to the configuration station (30) for setting the parameters of the monitoring apparatus (10). The parameters are unique and specific for the monitoring apparatus (10) and the parameters are preferably stored in storage at the monitoring apparatus (10). The monitoring apparatus (10) is required to undergo a training procedure on-site to account for each site’s unique characteristics i.e, number and type of streetlarnps, manufacturing tolerance, installation variation etc, and to yield the correction factors corresponding to the number of streetlarnps and variable supply voltages.

The monitoring apparatus (10) of the present invention measures the voltage and current of p!ura!ity of streetlarnps connected in a loop at specified time intervals and transmits these measurements to the server (20) via the communication network. If there are network issues during transmitting the measurements, the monitoring apparatus (10) would retry the transmission up to a specified maximum retry count before the monitoring apparatus (10) stops transmitting. In a preferred embodiment, the monitoring apparatus (10) is seif-reconfigurable via the configuration station (30) if the transmitters fails to transmit the real-time data to the server (20). Fig . 6 illustrates steps of self-configuring the monitoring apparatus (10) (300) in accordance to the present invention. The step of self-configuring the monitoring apparatus (10) (300) starts with a sub-step of connecting the configuration station (30) to the monitoring apparatus (10) via wired or wireless networking technology (310). Then the configuration station (30) sends a command to the monitoring apparatus (10) to halt the monitoring apparatus (10) operation and enter into configuration mode (320). The configuration station (30) starts sending configuration commands to the monitoring apparatus (10). The monitoring apparatus (10) decodes these commands to parse the parameters (330) and initiates a routine to write the parameters into the storage in the monitoring apparatus (10) (340) preferably into a non-volatile memory of the storage. Then, the configuration station (30) sends another command to the monitoring apparatus (10) to restart its operation (350) Upon receiving this command, the monitoring apparatus (10) is seif-reset,

The server (20) may be a cloud-based server to receive the real-time voltage and current from the monitoring apparatus (10). The server (20) further comprising the processor to receive real-time data measured by the monitoring apparatus (10). The processor is configured to calculate calibration coefficients to acquire ideal current drawn by the plurality of streeilamps operating normally. The processor is also used to calculate correction factors to normalize the real-time current. The processor also determines a! least one faulty streetlamp by comparing the normalized current with the ideal current. In addition to that, the processor also determines if the monitoring apparatus (10) is faulty by monitoring time interval to receive the real-time current from the monitoring apparatus (10),

One server (20) may also receive the real-time voltage and current from a plurality of monitoring apparatuses (10) via wired or wireless networking technology and consequently notifies the monitoring station (40) if faulty is detected. Server storage may be implemented to manage the real-time data with its corresponding monitoring apparatus (10) to store which real-time voltage and current belongs to which monitoring apparatus (10). A user interface may also be included at the server (20) to configure settings of the server (20) and displaying alert or status of the monitoring apparatus (10).

In a preferred embodiment, the server (20) performs fault detection computation either periodically on a specified time interval, or asynchronously when every time the server (20) receives the real-time data from the monitoring apparatus (10). The server (20) also performs periodic checking on the timestamp of latest current measurements received from the plurality of monitoring apparatuses (10) to determine if the monitoring apparatus (10) is faulty.

The configuration station (30) is used to configure parameters for the monitoring apparatus (10) comprises a computing device to run a suitable software application to setup the parameters. In a preferred embodiment, the parameters further comprising a rate to measure the real-time voltage and current by the sensors, a retry count to transmit the real-time voltage and current to the server (20) via the communication network, settings of the server (20) and setting of the communication network. The monitoring station (40) is configured to receive alert from the server (20) once at least a streeilamp or the monitoring apparatus (10) is determined faulty. In an embodiment, an alarm may be raised and maintenance personnel is informed via mobile application, message notification or initiated by a central command centre. The monitoring station. (40) may comprise of a computing device and a suitable software application running on the computing device to receive faulty alert and status updates from the server (20) via push notification.

The terms“a” and“an,” as used herein, are defined as one or more than one. The term“plurality,” as used herein, is defined as two or more than two. The term“another,” as used herein, is defined as at least a second or more. The terms“including” and/or “having,” as used herein, are defined as comprising (i.e., open language).

While this invention has been particularly shown and described with reference to the exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention as defined by the appended claims.

Claims

1 A method (100) of detecting at least one faulty streetiamp, characterized by the steps of:

deriving calibration coefficient and calculating ideal current (110) by calibrating a monitoring apparatus (10) connected in series to a plurality of streetlamps and a power supply;

calculating correction factors (120) by performing on-site training for the monitoring apparatus (10) connected in series to the plurality of streetlamps and the power supply;

measuring real-time current (130) for monitoring the plurality of streetlamps using the monitoring apparatus (10) and sending the real-time current to a server (20);

normalizing the real-time current ( 50) by using a processor at the server (20) to obtain normalized current by multiplying the real-time current with the correction factors; and

determining at least one faulty streetiamp (160) by comparing the normalized current with the ideal current by the processor, wherein at least one streetiamp is determined faulty if the normalized current is less than the ideal current.

2. The method (100) according to claim 1 , wherein deriving calibration coefficient and calculating ideal current (110) by calibrating a monitoring apparatus (10) connected in series to a plurality of streetlamps and a power supply further comprising steps of:

measuring a plurality of currents drawn by the plurality of streetlamps operating normally (111 ) powered by variable calibration voltages,

wherein the variable calibration voltages start from a minimum supply voltage and is increased with a predetermined voltage difference until a maximum supply voltage for each current measurement, and

wherein the plurality of streetlamps is turned on gradually for each calibration voltage;

modelling a number of streetlamps and the current measurements for each calibration voltage into polynomial factor (112); deriving calibration coefficient for each calibration voltage from the polynomial factor (113);

calculating a plurality of idea! currents drawn by the plurality of streetiamps for the variable calibration voltages (1 14) by multiplying the calibration coefficient for each calibration voltage with a particular number of streetiamps for all the variable calibration voltages; and

configuring the calibration coefficients and the plurality of ideal current into the server (20) (115).

3. The method (100) according to claim 1 , wherein calculating correction factors (120) by performing on-site training for the monitoring apparatus (10) connected in series to the plurality of streetiamps and the power supply comprising steps of: receiving a plurality of supply voltages and currents drawn by the plurality of streetiamps operating normally (121 ), measured by the monitoring apparatus (10);

identifying a minimum and maximum supply voltages (122) from the plurality of supply voltages measured by the monitoring apparatus (10);

creating groups of voltages (123) by dividing the difference between the maximum and minimum value of the supply voltages with a predetermined voltage difference, wherein each group represents a range of supply voltage;

grouping the plurality of measured currents (124) according to the measured supply voltage into the corresponding groups of voltages;

computing an actual current (125) for each group of voltages by calculating average current in each group of voltages;

calculating correction factor (126) for each group of voltages by dividing the ideal current with the actual current; and

configuring the correction factors into the server (20) (127).

4. The method (100) according to claim 3. wherein value of the correction factors for normalizing the real-time current (150) is chosen based on the group of voltages.

5. The method (100) according to claim 1 , wherein the method (100) further comprising a step of determining a faulty monitoring apparatus (10) by monitoring time interval for the server (20) receiving the real-time current (140) from the monitoring apparatus (10), wherein the monitoring apparatus (10) is determined faulty if the time interval is greater than a pre-determined time threshold.

6. The method {100} according to claim 1 , wherein the method {100} further comprising step of alerting a monitoring station (40) by the server (20) upon detecting at least one faulty streetia p or faulty monitoring apparatus (10) (170).

7 A system (200) for detecting at least one faulty streetiamp comprising:

a monitoring apparatus (10) comprising sensors connected in series0 between a plurality of streetlamps and a power supply to measure voltage and current drawn by the plurality of streetlamps;

a server (20) comprising a processor to receive measured voltage and current from the monitoring apparatus (10);

a configuration station (30) to configure parameters for the monitoring5 apparatus (10) and the server (20); and

a monitoring station (40) to receive alert from the server (20),

characterized in that:

the processor at the server (20) is configured to:

derive calibration coefficients and calculate ideal current drawn by0 the plurality of streetlamps operating normally;

calculate correction factors and normalize real time current measured by the monitoring apparatus (10);

determine at least one faulty streetiamp by comparing the ideal current with normalized current; and

D determine If the monitoring apparatus (10) is faulty.

8. The system (200) according to claim 7, wherein the monitoring apparatus (10) further comprising a transmitter to transmit the voltage and current to the server (20) via a communication network,

0

9, The system (200) according to claim 8, wherein the monitoring apparatus (10) is se!f-reconfigurab!e via the configuration station (30) if the transmitter fails to transmit the real-time current to the server (20) within a pre-determined time interval.

10. The system (200) according to claim 7, wherein the parameters further comprising:

a rate to measure the real-time current by the sensors;

a retry count to transmit the real-time current to the server (20} via the communication network;

settings of the server (20); and

settings of the communication network.