Description:A PORTABLE RESIDUAL CURRENT DEVICE WITH EARTH LEAKAGE FAULT INDICATION AND A METHOD THEREOF

TECHNICAL FIELD
[0001] The present disclosure relates generally to a portable residual current device and more particularly to a portable residual current device with earth leakage fault indication and a method thereof.

BACKGROUND
[0002] A portable residual current device (PRCD) is an electrical safety device designed to protect users from electric shocks or electrocution in various settings. It is a compact and easily transportable device that can be used with electrical equipment and tools in places where there is a heightened risk of electric shock due to wet conditions.
[0003] The portable residual current device operates by constantly monitoring the electrical current flowing through it. If it detects even a small leakage of current to the ground, such as through a user who comes into contact with a faulty electrical device, it will quickly interrupt the power supply, preventing harm to the user. This rapid response helps to minimize the duration and potential severity of an electric shock.
[0004] The portable residual current devices are particularly crucial in environments such as construction sites, outdoor events, workshops, and any location where electrical equipment is used in high humid areas. They add an extra layer of protection for workers, users, and the general public, reducing the risk of electrical accidents and injuries.
[0005] The existing portable residual current device primarily comprises an input terminal, an output terminal, a tripping unit, a main printed circuit board, and a sensing unit. The sensing unit is configured to monitor the presence of earth leakage current at the output terminal. In the event of an earth leakage fault, the sensing unit sends a fault signal to the main printed circuit board. On receiving the fault signal, the printed circuit board sends a tripping signal to the tripping unit. The tripping unit is configured to break the connection between the input terminal and the output terminal in the event of an earth leakage current.
[0006] In addition to the above-mentioned components, a status indication circuit is provided which primarily has a single LED. This LED remains illuminated during normal operation and turns off in the event of detection of earth leakage current. The LED of the status indication circuit turns off as the tripping unit breaks the connection between the input terminal and the output terminal.
[0007] The LED in the status indication circuit can be turned off for two main reasons: either the portable residual current device has tripped due to a fault condition, or there is a power failure situation.
[0008] The current portable residual current devices lack the capability to discern the specific cause behind turning off of the LED. This poses a serious risk of injury to users as they may unknowingly be exposed to live electrical current, assuming the LED has turned off due to a power failure situation.
[0009] Accordingly, there is a need for a portable residual current device that is capable of providing an indication to the individual in the event of an earth leakage fault. Further, there is a need for a method to indicate earth leakage fault in a portable residual current device.
SUMMARY
[0010] This summary is provided to introduce concepts related to a portable residual current device with earth leakage fault indication and a method to indicate earth leakage fault in a portable residual current device. The concepts are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
[0011] The present subject matter relates to a portable residual current device with earth leakage fault indication. The portable residual current device comprises an input terminal, an output terminal, a tripping unit, a printed circuit board, a sensing unit, an earth fault indication circuit, and a status indication unit. The input terminal is adapted to receive power from the source and the output terminal is adapted to supply the protected power to load. The tripping unit is in connection with the input terminal and the output terminal. The tripping unit is adapted to break the connection between the input terminal and the output terminal in fault condition. The printed circuit board is in connection with the tripping unit. The printed circuit board is configured to send a tripping signal to the tripping unit to break the connection between the input terminal and the output terminal in fault condition. The sensing unit is connected to the output terminal and the printed circuit board. The sensing unit is configured to monitor the output terminal for the presence of electrical leakage current. The earth leakage fault condition is in connection with the printed circuit board through an isolator. The earth fault indication circuit takes feedback from the printed circuit board and gives earth fault indication unit during a fault condition.
[0012] In an aspect, the isolator is an opto-isolator or a mechanical isolator.
[0013] In an aspect, the tripping unit is a mechanical switch capable of breaking the connection between the input terminal and the output terminal.
[0014] In an aspect, the sensing unit comprises a sensor sub-unit and a leakage current sensing sub-unit. The sensor sub-unit is in connection with the output terminal. The sensor sub-unit is configured to sense the output current of the output terminal. The leakage current sensing sub-unit is in connection with the sensor sub-unit and the printed circuit board. The leakage current sensing sub-unit is configured to receive a signal from the sensor sub-unit and transmit a fault signal to the printed circuit board when a fault condition is detected.
[0015] In an aspect, a user input unit is provided in connection with the printed circuit board configured to turn ON the device or perform a trip check on the user command.
[0016] In an aspect, the status indication unit is in connection with the printed circuit board and the earth fault indication circuit to indicate the ON state, Trip state, or Power fail state of the device.
[0017] In an aspect, the status indication unit comprises a first LED and a second LED to indicate the ON state, Trip state, or Power fail state of the device.
[0018] In an aspect, the printed circuit board gets power from the output terminal.
[0019] In an aspect, the earth fault indication circuit gets power from the input terminal.
[0020] In an aspect, in the fault condition, the leakage current sensing sub-unit sends the fault signal to the printed circuit board through which the earth fault indication circuit gets feedback of fault condition which the earth fault indication circuit indicate by illuminating the second LED through power from the input terminal.
[0021] In an aspect, in fault condition the tripping unit breaks the circuit between the input terminal and the output terminal resulting in inhibiting the illumination of the first LED of the status indication unit.
[0022] In an aspect, in normal condition, current from the input terminal coming to the earth fault indication circuit is bypassed through the isolator, thereby, inhibiting the illumination of the second LED through power from the input terminal.
[0023] The present subject matter further relates to a method to indicate earth leakage fault in a portable residual current device. The method comprises sensing, by a sensor sub-unit, the output current of the output terminal; receiving, by leakage current sensing sub-unit, signal from the sensor sub-unit; transmitting, by the leakage current sensing sub-unit, a fault signal in the event of earth leakage current detection, to the printed circuit board; transmitting, by the printed circuit board, a tripping signal to a tripping unit; receiving, by earth fault indication circuit, feedback from the printed circuit board to give earth fault indication through a status indication unit.
[0024] In an aspect, the earth fault indication circuit is in connection with the printed circuit board through an isolator.
[0025] In an aspect, the status indication unit comprises a first LED and a second LED.
[0026] In an aspect, the first LED of the status indication unit is illuminated and the second LED of the status indication unit is not illuminated in normal condition.
[0027] In an aspect, the first LED of the status indication unit is not illuminated and the second LED of the status indication unit is illuminated in trip condition.
[0028] In an aspect, the first LED of the status indication unit and the second LED of the status indication unit is not illuminated in power failure condition.
[0029] To further understand the characteristics and technical contents of the present subject matter, a description relating thereto will be made with reference to the accompanying drawings. However, the drawings are illustrative only and are not used to limit the scope of the present subject matter.
[0030] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF FIGURES
[0031] The illustrated embodiments of the present disclosure will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example and simply illustrates certain selected embodiments of devices, systems, and processes that are consistent with the subject matter as claimed herein, wherein:
[0032] FIG. 1 illustrates a block diagram of a portable residual current device that can be utilized to implement one or more exemplary embodiments of the present disclosure;
[0033] FIG. 2 illustrates an opto-isolator that can be utilized to implement one or more exemplary embodiments of the present disclosure; and
[0034] FIG. 3 illustrates a flow chart of a method performed by the portable residual current device to indicate earth leakage fault that can be utilized to implement one or more exemplary embodiments of the present disclosure.
[0035] The figures depict embodiments of the present subject matter for the purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.

DETAILED DESCRIPTION
[0036] A few aspects of the present disclosure are explained in detail below with reference to the various figures. Example implementations are described to illustrate the disclosed subject matter, not to limit its scope, which is defined by the claims. Those of ordinary skill in the art will recognize a number of equivalent variations of the various features provided in the description that follows.
Definitions
[0037] In the disclosure hereinafter, one or more terms are used to describe various aspects of the present disclosure. For a better understanding of the present disclosure, a few definitions are provided herein for better understating of the present disclosure.
[0038] “Fault Condition” may be defined, in the context of the invention, as a situation where a fault or abnormality is detected in the electrical circuit. Specifically, it indicates the presence of a leakage current, which occurs when some of the electrical current flowing in the circuit diverts from its intended path and leaks to the earth or ground.
[0039] “Normal Operating Condition” may be defined, in the context of the invention, as a standard and safe state of electrical circuit or equipment where no fault or leakage current is detected. In this condition, the electrical current flows as intended without any diversion to the earth or ground.
[0040] “Trip Condition” is defined, in the context of the invention, as a situation where the device detects a fault or abnormality in the electrical circuit, specifically the presence of a residual current or leakage current.
[0041] “Power Failure Condition” is defined, in the context of the invention, as a situation where there is a loss of electrical power to the device or the electrical circuit it is protecting. This can occur due to various reasons, such as a power outage, disconnection of the power source, or a fault in the electrical supply.

EXEMPLARY IMPLEMENTATIONS
[0042] While the present disclosure may be embodied in various forms, there are shown in the drawings, and will hereinafter be described, some exemplary and non-limiting embodiments, with the understanding that the present disclosure is to be considered an exemplification of the invention and is not intended to limit the invention to the specific embodiments illustrated. Not all of the depicted components described in this disclosure may be required, however, and some implementations may include additional, different, or fewer components from those expressly described in this disclosure. Variations in the arrangement and type of the components may be made without departing from the scope of the claims as set forth herein.
[0043] The primary purpose of a portable residual current device is to protect the user against electric shock resulting from earth leakage current. The existing portable residual current device has a status indication unit that is capable of indicating the ON state and fault condition. The status indication unit has a single LED to indicate the ON state, the fault condition, and the power failure situation.
[0044] The current portable residual current device (PRCD) has a limitation due to its single LED, which makes it incapable of distinguishing between a fault condition and a power failure situation. As a consequence, the primary purpose of the PRCD might be compromised, as users may be unable to differentiate between the two scenarios and inadvertently expose themselves to the risk of electric shock.
[0045] To prevent users from electric shocks, there is a necessity to provide a portable residual current device with earth leakage fault indication.
[0046] To achieve this goal of indication of earth leakage fault, a portable residual current device with earth fault indication may be utilized. The portable residual current device is described in more detail below.
[0047] FIG. 1 illustrates a block diagram of a portable residual current device that can be utilized to implement one or more exemplary embodiments of the present disclosure. The portable residual current device 100 comprises an input terminal 101, an output terminal 102, a tripping unit 103, a printed circuit board 104, a sensing unit, an earth fault indication circuit 105, and a status indication unit 106. The portable residual current device 100 has an input terminal 101 and an output terminal 102. The input terminal 101 is connected to the power source. The input terminal 101 is designed to plug into a standard electrical outlet or socket. The input terminal 101 is configured to receive power from the power source. The output terminal 102 is connected to an electrical device or load. The output terminal 102 is configured to supply power to the electrical device or load. The function of the portable residual current device 100 is to monitor the electrical current flowing between the input terminal 101 and the output terminal 102.
[0048] The monitoring of the electrical current flowing between the input terminal 101 and the output terminal 102 is performed by the sensing unit. The sensing unit is connected to the output terminal 102 and the printed circuit board 104. The primary function of the sensing unit is to detect and monitor the electrical current flowing between the input terminal 101 and the output terminal 102. The sensing unit detects leakage currents which occur when there is an unintended path for the electrical current to flow to the ground. Such leakage current can be caused by faults in electrical devices or when a user comes into contact with the live electrical parts.
[0049] The sensing unit comprises a sensor sub-unit 107a and a leakage current sensing sub-unit 107b. The sensor sub-unit 107a is in connection with the output terminal 102. The sensor sub-unit 107a comprises a coil. The sensor sub-unit 107a is configured to sense the output current of the output terminal 102. The leakage current sensing sub-unit 107b is in connection with the sensor sub-unit 107a and the printed circuit board 104. The leakage current sensing sub-unit 107b is configured to receive a signal from the sensor sub-unit 107a and transmit a fault signal to the printed circuit board 104 when a fault condition is detected. On receiving the fault signal from the leakage current sensing sub-unit 107b, the printed circuit board 104 sends a tripping signal to the tripping unit 103 to break the connection between the input terminal 101 and the output terminal 102.
[0050] The tripping unit 103 is in connection with the input terminal 101 and the output terminal 102. The tripping unit 103 is adapted to break the connection between the input terminal 101 and the output terminal 102. In an aspect of the invention, the tripping unit 103 is a mechanical switch capable of swiftly breaking the connection between the input terminal 101 and the output terminal 102, thus interrupting the power supply. This results in cutting off the electrical flow and quickly disconnects the connected electrical device or equipment from the power source. The tripping unit 103 is highly sensitive and responsive.
[0051] The printed circuit board 104 is in connection with the tripping unit 103, the leakage current sensing sub-unit 107b, and the status indication unit 106. The printed circuit board 104 gets power from the output terminal 102. The printed circuit board 104 is configured to receive fault signal from the leakage current sensing sub-unit 107b in the event of the leakage current sensing sub-unit 107b detecting leakage current. On receiving the fault signal, the printed circuit board 104 is configured to transmit a tripping signal to the tripping unit 103. The printed circuit board is further connected to a user input unit 108. The user input unit 108 is configured to turn ON the portable residual current device 100 or to perform a trip check.
[0052] The printed circuit board 104 is further connected to the earth fault indication circuit 105 through an isolator 109. In an aspect, isolator 109 is either a mechanical isolator or an opto-isolator. The earth fault indication circuit 105 is configured to take feedback from the printed circuit board 104 and gives earth fault indication through the status indication unit 106 during the fault condition. The status indication unit 106 has at least two LEDs. The first LED is in connection with the printed circuit board 104. The first LED is configured to indicate if the power source is providing power to the input terminal 101. Thus, when the first LED is illuminated it means that the portable residual current device 100 is in the ON state and when the first LED is not illuminated it indicates that the portable residual current device is in the OFF state and there is a power failure situation.
[0053] The second LED of the status indication unit 106 is in connection with the earth fault indication circuit 105. The earth fault indication circuit 105 takes feedback from the printed circuit board 104 and gives earth fault indication through the second LED of the status indication unit 106. The earth fault indication circuit gets power from the input terminal 101. This ensures that the second LED illuminates even after the tripping unit 103 breaks the connection between the input terminal 101 and the output terminal 103.
[0054] In the normal operating condition, current from the input terminal 101 coming to the earth fault indication circuit 105 is bypassed through the isolator 109, thereby, inhibiting the illumination of the second LED through power from the input terminal 101.
[0055] In the fault condition, the leakage current sensing sub-unit 107b transmits the fault signal to the printed circuit board 104 which in turn provides feedback to the earth fault indication circuit 105 to illuminate the second LED indicating earth leakage fault. The tripping unit 103 breaks the connection between the input terminal 101 and the output terminal 102 resulting in inhibiting the illumination of the first LED of the status indication unit 106.
[0056] FIG. 2 illustrates an opto-isolator that can be utilized to implement one or more exemplary embodiments of the present disclosure. The opto-isolator 200 primarily has a transmitter 201 and a receiver 202. The transmitter 201 is connected to the printed circuit board 104 and the receiver 202 is connected to the earth fault indication circuit 105. In an aspect, the transmitter 201 is an LED and the receiver 202 is a photo sensor.
[0057] FIG. 3 illustrates a flow chart of a method performed by the portable residual current device to indicate earth leakage fault that can be utilized to implement one or more exemplary embodiments of the present disclosure. At step 302, the sensor sub-unit 107a is configured to sense the output current of the output terminal 102. The sensor sub-unit 107a is in connection with the output terminal 102. The sensor sub-unit 107a is configured to sense the output current of the output terminal 102.
[0058] At step 304, leakage current sensing sub-unit 107b receives a signal from the sensor sub-unit 107a. The leakage current sensing sub-unit 107b is in connection with the sensor sub-unit 107a and the printed circuit board 104. The leakage current sensing sub-unit 107b is configured to receive a signal from the sensor sub-unit 107a about the sensed output current from the output terminal 102.
[0059] At step 306, the leakage current sensing sub-unit 107b transmits a fault signal in the event of earth leakage current detection to the printed circuit board 104. The connection between the tripping unit 103, leakage current sensing sub-unit 107b, and status indication unit 106 is established through the printed circuit board 104. Power is supplied to the printed circuit board 104 from the output terminal 102. Moreover, the printed circuit board 104 is designed to receive a fault signal from the leakage current sensing sub-unit 107b if it detects any leakage current.
[0060] At step 308, the printed circuit board 104 transmits a tripping signal to tripping unit 103. The tripping unit 103 is connected to both the input terminal 101 and the output terminal 102. Its primary function is to interrupt the connection between these terminals 101, 102, effectively halting the electrical flow and rapidly disconnecting the connected electrical device or equipment from its power source. The tripping unit 103 boasts high sensitivity and responsiveness, ensuring swift action in case of any electrical anomalies.
[0061] At step 310, the earth fault indication circuit 105 receives feedback from the printed circuit board 104 to give earth fault indication through status indication unit 106. The printed circuit board 104 is additionally linked to the earth fault indication circuit 105 via an isolator 109. This configuration enables the earth fault indication circuit 105 to receive feedback from the printed circuit board 104 and, in the event of a fault condition, provides an earth fault indication through the status indication unit 106. The status indication unit 106 is equipped with a minimum of two LEDs, allowing for clear visual signaling of the fault status.
[0062] The second LED in the status indication unit 106 is directly linked to the earth fault indication circuit 105. Through feedback from the printed circuit board 104, the earth fault indication circuit 105 activates the second LED to indicate an earth fault condition. To ensure uninterrupted operation, the earth fault indication circuit 105 draws power from the input terminal 101, ensuring that the second LED continues to illuminate even after the tripping unit 103 has disconnected the connection between the input terminal 101 and the output terminal 102.
WORKING OF THE SUBJECT MATTER
[0063] The portable residual current device is configured to indicate three different operating conditions of the device, namely, ON state, Trip state, and Power fail state.
[0064] Case-I: First LED ON and Second LED OFF
[0065] This indication on the portable residual current device indicates that the device is in an ON state.
[0066] Case-II: First LED OFF and Second LED OFF
[0067] This indication on the portable residual current device indicates that there is a Power failure.
[0068] Case-III: First LED OFF and Second LED ON
[0069] This indication on the portable residual current device indicates that the device is in a Trip state. It means there is an earth leakage fault current.
ADVANTAGES
The proposed portable residual current device has the capability to discern the specific cause behind turning off of the LED indication. Particularly, the proposed portable residual current device can specify whether the cause is earth leakage fault or power failure. Accordingly, the proposed portable residual current device provides better safety to the users.
[0070] The above description does not provide specific details of the manufacture or design of the various components. Those of skill in the art are familiar with such details, and unless departures from those techniques are set out, techniques, known, related art or later developed designs and materials should be employed. Those in the art are capable of choosing suitable manufacturing and design details.
[0071] Further, the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting to disclosure. It will be appreciated that several of the above-disclosed and other features and functions, or alternatives thereof, may be combined into other systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may subsequently be made by those skilled in the art without departing from the scope of the present disclosure as encompassed by the following claims.
[0072] The claims, as originally presented and as they may be amended, encompass variations, alternatives, modifications, improvements, equivalents, and substantial equivalents of the embodiments and teachings disclosed herein, including those that are presently unforeseen or unappreciated, and that, for example, may arise from applicants/patentees and others.
[0073] It will be appreciated that variants of the above-disclosed and other features and functions, or alternatives thereof, may be combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.
, Claims:We Claim:
1. A portable residual current device (100) with earth leakage fault indication, the device (100) comprises:
an input terminal (101) and an output terminal (102), wherein the input terminal (101) is adapted to receive power from the source and the output terminal (102) is adapted to supply the protected power to load;
a tripping unit (103) in connection with the input terminal (101) and the output terminal (102), wherein the tripping unit (103) is adapted to break the connection between the input terminal (101) and the output terminal (102) in fault condition;
a printed circuit board (104) in connection with the tripping unit (103), wherein the printed circuit board (104) is configured to send a tripping signal to the tripping unit (103) to break the connection between the input terminal (101) and the output terminal (102) in fault condition;
a sensing unit connected to the output terminal (102) and the printed circuit board (104), wherein the sensing unit is configured to monitor the output terminal (102) for the presence of electrical leakage current;
an earth fault indication circuit (105) in connection with the printed circuit board (104) through an isolator (109), wherein the earth fault indication circuit (105) takes feedback from the printed circuit board (104) and gives earth fault indication through a status indication unit (106) during a fault condition.
2. The device (100) as claimed in claim 1, wherein the isolator (109) is an opto-isolator or a mechanical isolator.

3. The device (100) as claimed in claim 1, wherein the tripping unit (103) is a mechanical switch capable of breaking the connection between the input terminal (101) and the output terminal (102).
4. The device (100) as claimed in claim 1, wherein the sensing unit comprises:
a sensor sub-unit (107a) in connection with the output terminal (102), wherein the sensor sub-unit (107a) is configured to sense the output current of the output terminal (103); and
a leakage current sensing sub-unit (107b) in connection with the sensor sub-unit (107a) and the printed circuit board (104), wherein the leakage current sensing sub-unit (107b) is configured to receive a signal from the sensor sub-unit (107a) and transmit a fault signal to the printed circuit board (104) when a fault condition is detected.
5. The device (100) as claimed in claim 1, wherein a user input unit (108) is provided in connection with the printed circuit board (104) configured to turn ON the device (100) or perform a trip check on the user command.
6. The device (100) as claimed in claim 1, wherein the status indication unit (106) is in connection with the printed circuit board (104) and the earth fault indication circuit (105) to indicate the ON state, Trip state, or Power fail state of the device.
7. The device (100) as claimed in claim 1, wherein the status indication unit (106) comprises a first LED and a second LED to indicate the ON state, Trip state, or Power fail state of the device (100)
8. The device (100) as claimed in claim 1, wherein the printed circuit board (104) gets power from the output terminal (102).
9. The device (100) as claimed in claim 1, wherein the earth fault indication circuit (105) gets power from the input terminal (101).
10. The device (100) as claimed in claim 1, wherein in the fault condition, the leakage current sensing sub-unit (107b) sends the fault signal to the printed circuit board (104) through which the earth fault indication circuit (105) gets feedback of fault condition which the earth fault indication circuit (105) indicate by illuminating the second LED through power from the input terminal (101).
11. The device (100) as claimed in claim 1, wherein in fault condition the tripping unit (103) breaks the circuit between the input terminal (101) and the output terminal (102) resulting in inhibiting the illumination of the first LED of the status indication unit (106).
12. The device (100) as claimed in claim 1, wherein in normal condition, current from the input terminal (101) coming to the earth fault indication circuit (105) is bypassed through the isolator (109), thereby, inhibiting the illumination of the second LED through power from the input terminal (101).
13. A method (300) to indicate earth leakage fault in a portable residual current device (100), the method (300) comprises:
sensing (302), by a sensor sub-unit (107a), the output current of the output terminal (102);
receiving (304), by leakage current sensing sub-unit (107b), signal from the sensor sub-unit (107a);
transmitting (306), by the leakage current sensing sub-unit (107b), a fault signal in the event of earth leakage current detection, to the printed circuit board (104);
transmitting (308), by the printed circuit board (104), a tripping signal to a tripping unit (103);
receiving (310), by earth fault indication circuit (105), feedback from the printed circuit board (104) to give earth fault indication through a status indication unit (106).
14. The method (300) as claimed in claim 13, wherein the earth fault indication circuit (105) is in connection with the printed circuit board (104) through an isolator (109).
15. The method (300) as claimed in claim 13, wherein the status indication unit (106) comprises a first LED and a second LED.
16. The method (300) as claimed in claim 13, wherein the first LED of the status indication unit (106) is illuminated and the second LED of the status indication unit (106) is not illuminated in normal condition.
17. The method (300) as claimed in claim 13, wherein the first LED of the status indication unit (106) is not illuminated and the second LED of the status indication unit (106) is illuminated in trip condition.
18. The method (300) as claimed in claim 13, wherein the first LED of the status indication unit (106) and the second LED of the status indication unit (106) is not illuminated in power failure condition.