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Zhao Y.,Northeastern University | De Palma J.-F.,Mersen United States Newburyport MA LLC | Mosesian J.,Mersen United States Newburyport MA LLC | Lyons R.,Mersen United States Newburyport MA LLC | And 2 more authors.
IEEE Transactions on Industrial Electronics | Year: 2013

Fault analysis in solar photovoltaic (PV) arrays is a fundamental task to protect PV modules from damage and to eliminate risks of safety hazards. This paper focuses on line-line faults in PV arrays that may be caused by short-circuit faults or double ground faults. The effect on fault current from a maximum-power-point tracking of a PV inverter is discussed and shown to, at times, prevent overcurrent protection devices (OCPDs) to operate properly. Furthermore, fault behavior of PV arrays is highly related to the fault location, fault impedance, irradiance level, and use of blocking diodes. Particularly, this paper examines the challenges to OCPD in a PV array brought by unique faults: One is a fault that occurs under low-irradiance conditions, and the other is a fault that occurs at night and evolves during 'night-to-day' transition. In both circumstances, the faults might remain hidden in the PV system, no matter how irradiance changes afterward. These unique faults may subsequently lead to unexpected safety hazards, reduced system efficiency, and reduced reliability. A small-scale experimental PV system has been developed to further validate the conclusions. © 1982-2012 IEEE.


Zhao Y.,Northeastern University | Lehman B.,Northeastern University | Ball R.,MERSEN United States Newburyport MA LLC | Mosesian J.,MERSEN United States Newburyport MA LLC | De Palma J.-F.,MERSEN United States Newburyport MA LLC
Conference Proceedings - IEEE Applied Power Electronics Conference and Exposition - APEC | Year: 2013

Solar photovoltaic (PV) arrays are unique power sources that may have uncleared fault current when utilizing conventional overcurrent protection devices. To monitor the PV operation and detect these unnoticed faults, outlier detection rules have been proposed for fault detection based on instantaneous PV string current. This paper discusses three rules in detail: 3-Sigma rule, Hampel identifier, and Boxplot rule. Unlike other methods, the proposed methods do not require weather measurement or efforts in model training. Our experimental results show that Hampel identifier and Boxplot rule may be recommended for PV fault detection. Furthermore, the proposed models become more reliable as the number of PV measurements increases. The developed methods may be integrated with PV monitoring system for real-time operation. © 2013 IEEE.


Fontaine M.D.,National Fire Protection Assoc. | Walsh P.,Mersen United States Newburyport MA LLC
Conference Record of the 2012 IEEE IAS Electrical Safety Workshop, ESW 2012 | Year: 2012

This paper suggests a method for calculating the incident energy and the arc flash boundary (AFB) distance for dc systems when an arc-in-a-box situation is involved. The method uses the dc maximum power method and a multiplying factor instead of using distance exponents. The method may also be used for an arc-in-open-air by using a multiplying factor of 1. It is based on the basic assumption that the spherical energy density can be increased to a new value to account for the additional reflected heat radiation from a box situation and that the ratio of the new value to the spherical energy density equals a multiplying factor for correcting - from the energy density for an arc-in-open-air situation to an arc-in-a-box situation, based on a simplified equation or methodology. When calculating the AFB, the method requires the use of an iterative process, since the multiplying factor is a nonlinear variable and is based on the distance from the arc. This paper should provide a good starting point for further discussion and development regarding dc arc-in-a-box situations. © 2012 IEEE.


Zhao Y.,Northeastern University | Yang L.,Northeastern University | Lehman B.,Northeastern University | De Palma J.-F.,MERSEN United States Newburyport MA LLC | And 2 more authors.
Conference Proceedings - IEEE Applied Power Electronics Conference and Exposition - APEC | Year: 2012

Because of the non-linear output characteristics of PV arrays, a variety of faults may be difficult to detect by conventional protection devices. To detect and classify these unnoticed faults, a fault detection and classification method has been proposed based on decision trees (DT). Readily available measurements in existing PV systems, such as PV array voltage, current, operating temperature and irradiance, are used as "attributes" in the training and test set. In experimental results, the trained DT models have shown high accuracy of fault detection and fault classification on the test set. © 2012 IEEE.


Patent
MERSEN United States NEWBURYPORT MA LLC | Date: 2013-06-05

A voltage suppression device for suppressing voltage surges in an electrical circuit having a voltage sensitive assembly comprised of a plurality of tubular sections within a tubular casing.


Patent
Mersen United States Newburyport MA LLC | Date: 2016-06-17

A printed circuit board (PCB) via fuse including a non-conductive substrate having a pair of terminal conductors, a plurality of jumper conductors and one or more through-hole vias that electrically connect the terminal conductors and jumper conductors. The through-hole vias function as the fuse element of the PCB via fuse.


Patent
MERSEN United States NEWBURYPORT MA LLC | Date: 2013-03-14

An electric fuse, having a first fusible element and a disconnect section electrically connected in series to the first fusible element. The disconnect section is comprised of a first stationary contact, a second stationary contact and a movable contact movable from a first position electrically connecting the first and second stationary contacts to form a conductive path through the disconnect section to a second position electrically separating the first and second stationary contacts from each other and terminating the conductive path through the disconnect section. A retaining element holds the movable contact in the first position, the retaining element operable to release the movable contact from the first position when activated by an electrical (actuation) signal from an external source.


Patent
MERSEN United States NEWBURYPORT MA LLC | Date: 2013-03-14

A medium voltage controllable fuse that provides fast activation in response to both low current and high current faults, and at load currents in response to an external condition detected by an external sensing device. The controllable fuse includes a high-current fault interrupting section, a low-current fault interrupting section, and a trigger element responsive to a fuse controller.


Patent
Mersen United States Newburyport Ma LLC | Date: 2014-12-10

A voltage suppression device (10) for suppressing voltage surges in an electrical circuit having a voltage sensitive assembly (52) comprised of a plurality of tubular sections within a tubular casing (32).


Patent
Mersen United States Newburyport MA LLC | Date: 2014-04-14

An arc suppressor fixable to a fusible element to suppress electrical arcs and prevent the spread of electric arc burn-back. The arc suppressor includes first and second inner members comprised of pre-cured silicone rubber, and first and second outer members comprised of an arc suppressing material (e.g., melamine). The inner and outer members form a sandwich around a portion of the fusible element, wherein the first inner member is located adjacent to a first surface of the fusible element and the second inner member is located adjacent to an opposing second surface of the fusible element. The first outer member is located adjacent to the first inner member and the second outer member is located adjacent to the second inner member. Mechanical fasteners tightly engage together the first and second inner members, the fusible element, and the first and second outer members.

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