Claims:
1. An external neutral current sensor operatively coupled to an MCCB, the external neutral current sensor comprising:
a termination arrangement that is configured to provide multiple types of termination arrangements such as but not limited to box clamp, lug, link and rear terminal stud arrangement;
a control terminal block wherein a current transformer is operatively coupled to the external neutral current sensor that is configured to power up an electronic trip unit of an MCCB; and
a Rogowski coil configured to measure the current through the neutral circuit wherein said Rogowski coil and a voltage moduleare configured for measurement of power through the neutral circuit.
2. The arrangement as claimed in claim 1, wherein external neutral sensor further comprises of a neutral conductor coupled with at least one current sensor.
3. The arrangement as claimed in claim 1, wherein saidRogowski coilexecute current measurement of the neutral conductor of electrical circuit.
4. The arrangement as claimed in claim 1, wherein a combination of Rogowski sensor and voltage module is configured to execute precise power measurement of the electrical circuit.
5. The apparatus as claimed in claim 1, wherein said termination arrangement is operatively coupled to an electronic trip unit of the MCCB.
6. The apparatus as claimed in claim 1, wherein the current transformer harvests power from the neutral conductor and feeds the power to the trip unit for powering up the MCCB trip unit.
7. The apparatus as claimed in claim 1, wherein said control terminal block provides flexibility to a user to use an auxiliary conductor arrangement of a suitable size.
, Description:
TECHNICAL FIELD

[0001] The present disclosure relates generally to protection devices for protecting electrical circuits against fault current conditions. In particular, the present invention discloses a termination arrangement of external neutral current sensors for MCCB.

BACKGROUND
[0002] Electrical systems in residential, commercial and industrial applications usually include a panel for receiving electrical power from a utility source. This power is then routed through overcurrent protection devices to designated branch circuits supplying one or more loads. Further, these overcurrent devices are typically circuit breakers that are capable of interrupting electrical current in case of fault that reduces risk of injury or potential of property damage from a resulting fire.
[0003] An external neutral current sensor is a device used along with an MCCB for sensing the current flowing through neutral conductor of an electrical circuit. In order to save the installation cost, instead of using four pole circuit breakers (in which the neutral pole sensor is integrated to the circuit breaker), people install three pole circuit breaker along with external neutral sensor on the neutral conductor. The overall cost of circuit breaker along with external neutral sensor turns out to be cheaper than the cost of four pole circuit breaker. Thus for three phase four wire distribution system circuit breaker along with external neutral sensor turns out to be an economical solution.
[0004] Conventional external neutral sensors are sensors that are coupled with a conductor passing through its center recess. These sensors offer limited type of power circuit termination arrangements limiting the choice of users for specific termination. Further, conventional external neutral sensors did not have provision of powering up the electronic trip unit through the sensors.
[0005] Existing termination arrangements for current sensors for use with a circuit breaker only provide options that are confined to arrangements such as box clamp, lug, link, etc. Hence, there is no arrangement for rear terminal stud type arrangement within same module that can enhance the performance of the termination arrangement.
[0006] Thus there is a need of a termination arrangement of compact external neutral current sensors for MCCB which caters to the choice of users for specific termination such as box clamp, lug, link and rear terminal stud arrangement that provides flexibility to the user to choose the termination arrangement exactly similar to MCCB and further helps the user to minimize effort, inventory and optimize space within the MCCB.

OBJECTS OF THE INVENTION

[0007] A general object of the present disclosure is to provide a termination arrangement for external neutral current sensor that can detect current through the neutral and in case of fault can give trip signal to MCCB within an electrical circuit.
[0008] Another object of the present disclosure is to provide an external neutral current sensor that incorporates simple construction.
[0009] Another object of the present disclosure is to provide a termination arrangement for external neutral current sensor that provides flexibility to a user to accommodate different types of termination arrangements.
[0010] Another object of the present disclosure is to provide an external neutral current sensor that can power up an electronic trip unit of connected MCCB.
[0011] Another object of the present disclosure is to provide an external neutral current sensor that can provide precise current measurement through the neutral conductor.
[0012] Another object of the present disclosure is to provide ant external neutral current sensor that provide can facilitate electronic trip unit of MCCB for precise power measurement of an electrical circuit.
[0013] Another object of the present disclosure is to provide ant external neutral current sensor that reduces installation cost of an MCCB unit and termination arrangement.
[0014] Another object of the present disclosure is to provide ant external neutral current sensor that minimizes effort, inventory and optimizes space within an electrical panel.

SUMMARY

[0015] The present disclosure relates generally to protection devices for protecting electrical circuits against fault current conditions. In particular, the present invention discloses an external neutral current sensor for MCCB.The present disclosure provides anexternal neutral current sensor for an MCCB that minimizes effort, inventory and optimizes space within the MCCB.
[0016] In an aspect, external neutral current sensor is operatively coupled to an MCCB wherein the termination arrangement consists of a termination arrangement that is configured to provide multiple types of termination arrangements such as but not limited to box clamp, lug, link and rear terminal stud arrangement. a current transformer is one of the parts of the external neutral current sensor that is configured to power up an electronic trip unit of an MCCB, and a Rogowski coil is one of the parts of the external neutral current sensor that is configured to provide signal proportional to the measured current value current to the electronic trip unit of an MCCB. The voltage module is one of the parts of the external neutral current sensor that is configured to provide signal proportional to the measured voltage value to the electronic trip unit of an MCCB.
[0017] In an aspect, external neutral sensor further consists of a neutral conductor coupled with at least one current sensor wherein Rogowski sensor configured with current transformer execute current measurement of the neutral conductor of electrical circuit. Further, combination of Rogowski sensor and voltage module is configured to execute precise power measurement of the electrical circuit.
[0018] In an aspect, input current of the external neutral sensor can be used for monitoring purposes as well as protection from all type of system protection features such as overload, unbalanced current, earth fault condition, etc. To implement protection against such severe conditions, a precise measurement of current flowing through the circuit is achieved with the help of Rogowski sensor configured with the external neutral sensor and precise measurement of power is achieved through combination of Rogowski sensor and voltage module configured with the external neutral sensor, and thereafter, output of the combination of Rogowski sensor and voltage module is fed to the trip unit of the MCCB for measurement of power.
[0019] In an aspect, the external neutral sensoris operatively coupled to an electronic trip unit of the MCCB. In an embodiment, the current transformer harvest power from the neutral conductor and feeds the power to the trip unit for powering up the MCCB trip unit. In case power quality in distribution system is highly inferior or in case of highly unbalanced system, there is a very high amount of current flowing through the neutral conductor. In such scenario, it makes sense to power up the trip unit with the help of the neutral current. The power is harvested from neutral conductor through the current transformer and fed to the trip unit for powering up the trip unit. Thus, the electronic trip unit of the MCCB can be powered up through the external neutral sensor.
[0020] In an aspect, the control terminal block provides flexibility to a user to use an auxiliary conductor arrangement of a suitable size.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.
[0022] Fig. 1 illustrates an exemplary representation of an external neutral sensor along with MCCB and its control wiring arrangement in accordance with embodiments of the present disclosure.
[0023] Fig. 2A illustrates an exemplary isometric view of an external neutral sensor in accordance with embodiments of the present disclosure.
[0024] Fig. 2B illustrates an exemplary cross sectional view of an external neutral sensor in accordance with embodiments of the present disclosure.
[0025] Fig. 3A illustrates an exemplary representation of external neutral sensor with termination type lug in accordance with embodiments of the present disclosure.
[0026] Fig. 3B illustrates an exemplary representation of external neutral sensor with termination type link in accordance with embodiments of the present disclosure.
[0027] Fig. 3C illustrates an exemplary representation of external neutral sensor with termination type box clampin accordance with embodiments of the present disclosure.
[0028] Fig. 3D illustrates an exemplary representation of external neutral sensor with termination type rear termination in accordance with embodiments of the present disclosure.

DETAILED DESCRIPTION

[0029] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such details as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0030] Embodiments explained herein relate to protection devices for protecting electrical circuits against fault current conditions. In particular, the present invention discloses a termination arrangement of external neutral current sensors for MCCB.The present disclosure provides anexternal neutral current sensor for an MCCB that minimizes effort, inventory and optimizes space within an electrical panel.
[0031] In an aspect, external neutral current sensor is operatively coupled to an MCCB wherein the termination arrangement consists of a termination arrangement that is configured to provide multiple types of termination arrangements such as but not limited to box clamp, lug, link and rear terminal stud arrangement. The control termination is through a control terminal block..
[0032] In an aspect, the external neutral current sensors further consists of a neutral conductor coupled with at least one current sensor wherein Rogowski sensor configured with Rogowski coils execute current measurement of the neutral conductor of electrical circuit. Further, combination of Rogowski sensor and voltage module is configured to execute precise power measurement of the electrical circuit. A current transformer is operatively coupled to the external neutral current sensor that is configured to power up an electronic trip unit of an MCCB.
[0033] In an aspect, input current i.e. neutral conductor current of the external neutral current sensor can be used for monitoring purposes as well as protection from all type of system protection features such as overload, unbalanced current, earth fault condition, etc. To implement protection against such severe conditions, a precise measurement of current flowing through the circuit is achieved with the help of Rogowski sensor configured with the external neutral sensor and precise measurement of power is achieved through combination of Rogowski sensor and voltage module configured with the external neutral sensor, and thereafter, output of the combination of Rogowski sensor and voltage module is fed to the trip unit of the MCCB for measurement of power.
[0034] In an aspect, the external neutral current sensor is operatively coupled to an electronic trip unit of the MCCB. In an embodiment, the current transformer harvest power from the neutral conductor and feeds the power to the trip unit for powering up the MCCB trip unit. In case power quality in distribution system is highly inferior or in case of highly unbalanced system, there is a very high amount of current flowing through the neutral conductor. In such scenario, it makes sense to power up the trip unit with the help of the neutral current. The power is harvested from neutral conductor through the current transformer and fed to the trip unit for powering up the trip unit. Thus, the electronic trip unit of the MCCB can be powered up through the external neutral sensor.
[0035] In an aspect, the control terminal block provides flexibility to a user to use an auxiliary conductor arrangement of a suitable size.
[0036] Fig. 1 illustrates an exemplary representation of an external neutral sensor 102 along with MCCB 104 and its control wiring arrangement wherein connections are made through a flexible multi-core shielded cable 106 with suitable type of terminals to suite the MCCB 104.
[0037] In an aspect, external neutral sensor 102 incorporates simple construction and provides flexibility to user to accommodate different types of terminal arrangements such as box clamp, lug, link and rear terminal stud arrangement.
[0038] Fig. 2A and 2B illustrate exemplary inclined and cross sectional views of an external neutral sensor 102 respectively wherein external neutral sensor 102 consists of a current transformer 252, a set of Rogowski coil 254, a neutral conductor 256, a control terminal block 108, connecting leads 258, voltage module 260 and all said components are enclosed in an enclosure 262..
[0039] In an aspect, power is harvested from neutral conductor 256 through the current transformer 252 and fed to the trip unit for powering up the MCCB trip unit for its operation. Thus, the MCCB electronic trip unit can be powered up through the external neutral sensor 102.
[0040] In an aspect, for the measurement of power flowing through distribution system, voltage is tapped from the neutral conductor 256 by means of voltage module 260 as shown in FIG. 2B.
[0041] In an aspect, current input from either current transformer 252 can be used for measurement of current. The output from current transformer 252, Rogowski coils254and voltage tapping unit260 is tapped through their respective connecting leads258 and fed to the control terminal block 108. The external neutral sensor 102 is connected via control terminal block108 with the help of flexible multi-core shielded cable 106 to the MCCB 104.
[0042] In an aspect, nut retainers 266 are snap fitted to the external neutral sensor enclosures 262. The nut retainers retain the hex nut for connecting power termination bolt. The power connection of neutral conductor 256 is designed to provide flexibility to user.
[0043] Fig. 3A shows the arrangement of connection of external neutral sensor 102 with termination type lug (or cable) 302, wherein nut retainers 266 are used for the connection.
[0044] Fig. 3B shows the arrangement of connection of external neutral sensor 102 with termination type link (or extended terminal) 322, wherein nut retainers 266 are used for the connection.
[0045] Fig. 3Cshows the arrangements of connection of external neutral sensor 102 with termination type box clamp 342, wherein nut retainers 266 can be used for the connection.
[0046] Fig. 3Dshows the arrangement of connection of external neutral sensor 102 with termination type rear terminal (or rear studs) 364, wherein rear terminal holders 362 are used along with the rear terminal 364 to retain the rear terminal 364. Moreover, rear terminal holders 362 are used in place of nut retainers 266 which provide flexibility to the customer to use the rear terminal 364 in any predefined angle of termination.
[0047] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.

ADVANTAGES OF THE INVENTION

[0048] The present disclosure provides an external neutral current sensor that trips an electrical circuit in case of a fault current condition.
[0049] The present disclosure provides an external neutral current sensor that incorporates simple construction.
[0050] The present disclosure provides a termination arrangement for external neutral current sensor that provides flexibility to a user to accommodate different types of terminal arrangements.
[0051] The present disclosure provides an external neutral current sensor that can power up an electrical trip unit of an MCCB.
[0052] The present disclosure provides an external neutral current sensor that provides precise current measurement of the neutral conductor.
[0053] The present disclosure provides an external neutral current sensor that provides precise power measurement of an electrical circuit.
[0054] The present disclosure provides an external neutral current sensor that reduces installation cost of an MCCB unit and termination arrangement.
[0055] The present disclosure provides an external neutral current sensor that minimizes effort, inventory and optimizes space within an electrical panel.