Patent Description:
Electromagnetic devices, such as transformers are used to generate voltages utilizing alternating currents. The construction of these types of electromagnetic devices typically includes a central core constructed from of a highly permeable material to provide a required magnetic path. The ability of iron or steel to carry magnetic flux is much greater than it is in air, this is known as the permeability of the core and influences the materials used for the core portion of a transformer.

<CIT> describes detecting a partial discharge in a voltage transformer using a radio frequency current transformer operably connected to an electrostatic shield. <CIT> describes a sensor connected to an output of an AC-to-DC converter and a secondary bias power supply that receives power from a secondary winding shield.

Claim <NUM> defines an electrical fault detecting circuit, claim <NUM> defines a method of detecting a fault in a power transformer. In the following, any method and/or apparatus not falling within the scope of the appended claims are to be understood as examples helpful in understanding the invention.

In one aspect, the present disclosure relates to an electrical fault detecting circuit.

In another aspect, the present disclosure relates to a power transformer, including a former, a set of primary windings circumferentially wound about the former and connected with a transformer power input, a first insulation layer encircling the set of primary windings, a conductive shield layer circumferentially wound about the first insulation layer and energized at a predetermined voltage by an energization source, a second insulation layer encircling the conductive shield, a set of secondary windings encircling the second insulation layer and connected with a transformer power output, and a controller module connected with the conductive shield layer and configured to sense an actual voltage at the conductive shield layer and compare the sensed actual voltage with a voltage threshold, and when the sensed actual voltage exceeds the voltage threshold, determine an electrical fault is present in the power transformer.

In yet another aspect, the present disclosure relates to a method of detecting a fault in a power transformer having a conductive shield layer sandwiched between electrical insulating layers separating the conductive shield layer from a first conductor and a second conductor, the second conductor opposite the conductive shield layer from the first conductor, the method including sensing a voltage energizing the shield layer, comparing the sensed voltage to a threshold voltage value corresponding to a fault, and upon satisfaction of the comparison, providing a fault indication when the comparison indicates the presence of a fault.

The described aspects of the present disclosure are directed to a method and apparatus associated with an electromagnetic device, including but not limited to transformers or power transformers. One example environment where such a method and apparatus can be used includes, but is not limited to, a power distribution system for a vehicle, such as an aircraft. While a power distribution system for an aircraft is mentioned, it is also applicable to any commercial or residential environment using a power distribution system, electromagnetic device, transformer, or power transformer where input power is received in a primary set of windings, and based on the adaption or configuration of a secondary set of windings in a magnetic relationship with the primary windings, outputs a power different from the input power, to a downstream component, such as one or more electrical loads. Furthermore, aspects of the disclosure can be applicable in any circuit or power environment utilizing isolated switched mode power supplies, or the like.

While "a set of" various elements will be described, it will be understood that "a set" can include any number of the respective elements, including only one element. As used herein, the terms "axial" or "axially" refer to a dimension along a longitudinal axis of a component or along a longitudinal axis of the component. Also as used herein, while sensors can be described as "sensing" or "measuring" a respective value, sensing or measuring can include determining a value indicative of or related to the respective value, rather than directly sensing or measuring the value itself. The sensed or measured values can further be provided to additional components. For instance, the value can be provided to a controller module or processor, and the controller module or processor can perform processing on the value to determine a representative value or an electrical characteristic representative of said value.

In another non-limiting example, a control module can include comparing a first value with a second value, and operating or controlling operations of additional components based on the satisfying of that comparison. For example, when a sensed, measured, or provided value is compared with another value, including a stored or predetermined value, the satisfaction of that comparison can result in actions, functions, or operations controllable by the controller module. As used, the term "satisfies" or "satisfaction" of the comparison is used herein to mean that the first value satisfies the second value, such as being equal to or less than the second value, or being within the value range of the second value. It will be understood that such a determination may easily be altered to be satisfied by a positive/negative comparison or a true/false comparison. Example comparisons can include comparing a sensed or measured value to a threshold value or threshold value range.

While terms such as "power" can be used herein, it will be evident to one skilled in the art that these terms can be relative to, or related to respective voltages, currents, or a combination thereof, when describing aspects of the electrical circuit, or circuit operations. All directional references (e.g., radial, axial, upper, lower, upward, downward, left, right, lateral, front, back, top, bottom, above, below, vertical, horizontal, clockwise, counterclockwise) are only used for identification purposes to aid the reader's understanding of the disclosure, and do not create limitations, particularly as to the position, orientation, or use thereof. Connection references (e.g., attached, coupled, connected, and joined) are to be construed broadly and can include intermediate members between a collection of elements and relative movement between elements unless otherwise indicated. As such, connection references do not necessarily infer that two elements are directly connected and in fixed relation to each other. In non-limiting examples, connections or disconnections can be selectively configured, connected, or connectable to provide, enable, disable, or the like, an electrical connection between respective elements. In non-limiting examples, connections or disconnections can be selectively configured to provide, enable, disable, or the like, an electrical connection between respective elements. Non-limiting example power distribution bus connections or disconnections can be enabled or operated by way of switching, bus tie logic, or any other connectors configured to enable or disable the energizing of electrical loads downstream of the bus.

As used herein, a "system" or a "controller module" can include at least one processor and memory. Non-limiting examples of the memory can include Random Access Memory (RAM), Read-Only Memory (ROM), flash memory, or one or more different types of portable electronic memory, such as discs, DVDs, CD-ROMs, etc., or any suitable combination of these types of memory. The processor can be configured to run any suitable programs or executable instructions designed to carry out various methods, functionality, processing tasks, calculations, or the like, to enable or achieve the technical operations or operations described herein. The program can include a computer program product that can include machine-readable media for carrying or having machine-executable instructions or data structures stored thereon. Such machine-readable media can be any available media, which can be accessed by a general purpose or special purpose computer or other machine with a processor. Generally, such a computer program can include routines, programs, objects, components, data structures, algorithms, etc., that have the technical effect of performing particular tasks or implement particular abstract data types.

Additionally, as used herein, an electrical arc or arcing event is an unintended or undesired conduction of current across a traditionally non-conductive medium, such as air or an insulation layer. For example, in non-limiting instances, a parallel arc can include an arcing event at least partially connecting two points which are intended to be insulated from each other. In another non-limiting instance, a series arc can include an arcing event in which a conductive medium becomes non-conductive or poorly conductive between two parts of an intended conductive path. Furthermore, in non-limiting instances, an arcing event or an "arc fault" can include the unexpected power loss situation, regardless of whether there is an obvious arc manifestation (e.g. a visible or visually identifiable occurrence). In another non-limiting instance, a series arc can include an unexpected impedance. Electrical arcs might occur in an environment where, for example, physical defects in an electrical connection, or insulation thereof, cause a permanent or temporary loss in transmission capabilities.

The exemplary drawings are for purposes of illustration only and the dimensions, positions, order and relative sizes reflected in the drawings attached hereto can vary.

<FIG> illustrates a schematic view of a circuit <NUM> having electromagnetic device <NUM> configured, capable, or otherwise enabled to convert a first electrical power characteristic to a second electrical power characteristic, wherein the second electrical power characteristic is different from the first electrical power characteristic. As shown, the electromagnetic device <NUM> can include a transformer <NUM>, such as a power transformer.

As shown, a power source <NUM> adapted to generate or supply a first power having the first electrical power characteristic is connected with a set of primary windings <NUM> of the transformer <NUM>. In one non-limiting example of an isolated switched mode power supply, the power source <NUM> can be connected with the set of primary windings <NUM> by way of an input filtering and switching circuit <NUM>, whereby power or signal filters can filter the power supply from the power source <NUM>, and can selectively or controllably enable or disable the supplying of power from the power source <NUM> by way of switching capabilities. Aspects of the input filtering and switching circuit <NUM> are not germane to the aspects of the disclosure. In one example, the set of primary windings <NUM> can include a non-conductive layer or insulation layer about the windings to prevent conductive contact between the windings of the set of primary windings <NUM>, or conductive contact between the set of primary windings <NUM> and other conductive components of the circuit <NUM> or electromagnetic device <NUM>.

The primary windings <NUM> are in a magnetic relationship with a magnetically permeable core <NUM> of the transformer <NUM>, which is further in a magnetic relationship with a set of secondary windings <NUM>. The set of primary windings <NUM> are further electrically isolated (e.g. in a non-conductive relationship) from the set of secondary windings <NUM>, which is schematically shown by a dotted isolation barrier <NUM>. The isolation barrier <NUM> can include, but is not limited to, non-conductive or electrically insulating layers, wraps, coatings, or the like, or any electromagnetic interference layer.

The set of secondary windings <NUM> are further connected with a power output <NUM> having the second electrical power characteristics. In another non-limiting example, the set of secondary windings <NUM> can be connected with the power output <NUM> by way of a rectification and output filtering circuit <NUM>, whereby the power received by the set of secondary windings <NUM> is rectified and filtered prior to being delivered to the power output <NUM>. Aspects of the rectification and output filtering circuit <NUM> are also not germane to the aspects of the disclosure. In another example, the set of secondary windings <NUM> can include a non-conductive layer, dielectric layer, or insulation layer about the windings to prevent conductive contact between the windings of the set of secondary windings <NUM>, or conductive contact between the set of secondary windings <NUM> and other conductive components of the circuit <NUM> or electromagnetic device <NUM>.

The circuit <NUM> or electromagnetic device <NUM> can further include a feedback mechanism for operating the circuit <NUM> or electromagnetic device <NUM>. For example, the circuit <NUM> can include a feedback signal that receives or carries a feedback value from the power output <NUM>, by way of a signal or communication line <NUM>. The communication line <NUM> can carry or transmit the feedback value from the power line to a controller module <NUM> having a processor <NUM> and memory <NUM>. The controller module <NUM>, in turn, can selectively operate aspects of the circuit <NUM> or electromagnetic device <NUM>, such as the switching in the input filtering and switching circuit <NUM>, by way of control signal <NUM>. Thus, the controller module <NUM> can effect, enable, or operably control the supply of power to the set of primary windings <NUM> such that the expected or desired supply of power is delivered to the set of secondary windings <NUM> or power output <NUM>. In one non-limiting example, the communication line <NUM> can further provide the feedback value to an isolator <NUM> prior to delivering the feedback value to the controller module <NUM>. In this non-limiting example, the isolator <NUM> can be adapted or configured to, for instance, isolate the feedback for the set of primary winding <NUM> switching control signal <NUM>.

Aspects of the circuit <NUM> or electromagnetic device <NUM> can further be included wherein a fault detection circuit is included. As shown, the fault detection circuit can include an electrical conductor, such as a shielding layer <NUM> or sheath layer, extending between at least the set of primary windings <NUM> and the set of secondary windings <NUM>. While not shown in the schematic illustrations, the shielding layer or layers <NUM> can, for example, envelop, encircle, encompass, or be physically positioned between at least the set of primary windings <NUM> and the set of secondary windings <NUM>. In another non-limiting example, the shielding layer <NUM> can envelop, encircle, encompass, or be physically positioned between each of the windings <NUM>, <NUM>, as well as between the windings and other conductive components of the circuit <NUM>, the electromagnetic device <NUM>, the core <NUM>, or the like. Non-limiting examples of the shielding layer <NUM> can comprise a conductive foil, an electrostatic screen, or the like. In another non-limiting example, the shielding layer <NUM> can comprise of two or more separate portions in order to avoid having a shorted turn in the transformer <NUM>.

The shielding layer <NUM> can further be connected with a voltage divider <NUM> configured or adapted to energize the shielding layer <NUM> at a known or predetermined voltage. For instance, as shown, the voltage divider <NUM> can be arranged between the conductive output of the power source <NUM> and a ground <NUM> connection, and include resistors (shown as R1 and R2) such that the output between the resistors is the predetermined voltage. In non-limiting examples, the predetermined voltage output of the voltage divider <NUM> can be adapted, configured, or the like, the resistors R1, R2 can be selected such that the predetermined voltage output is not equal to either the voltage output of the power source <NUM>, the voltage output of the power output <NUM> or set of secondary windings <NUM>, or a grounded voltage (i.e. zero volts) value. In this sense, the shielding layer <NUM> can be energized or energizable with the predetermined voltage output from the voltage divider <NUM>.

The energized or energizable shielding layer <NUM> can be further connected with the controller module <NUM>, which can be adapted to sense or measure the voltage of the shielding layer <NUM>, by way of a voltage signal <NUM>. In this sense, the controller module <NUM> can include a voltage sensor (not shown) adapted or configured to detect, sense, or measure a voltage at the shielding layer <NUM>.

While a grounding connection <NUM> is shown, non-limiting examples of the circuit <NUM> can be included wherein the power source <NUM> or power output <NUM> is not relative to Earth ground <NUM>, but rather to another voltage. In this example, the other predetermined voltage output of the voltage divider <NUM> can also be configured, adapted, or the like is not equal to the other voltage replacing the ground connection <NUM>. Additionally, while the voltage divider <NUM> is shown relative to the power source <NUM>, the voltage divider <NUM> can be energized, or otherwise adapted, to receive power and supply the predetermined voltage output from an alternative power source or supply that is not the power source <NUM>. In non-limiting examples, a capacitor <NUM> can be include across the second resistor R2, and can operate to filter electromagnetic noise from being transmitted from the set of primary windings <NUM> to the set of secondary windings <NUM>. In one example, the capacitor <NUM> can filter the noise from an electromagnetic screen (not shown), or wherein the shielding layer <NUM> can act as an electromagnetic screen.

During operation of the circuit <NUM>, the fault detection circuit can be adapted or configured to provide fault protection, arc fault protection, fault detection, arc fault detection, or determination of a suspected, confirmed, or likely electrical fault event. As shown in <FIG>, an example first fault <NUM> is shown in the set of primary windings <NUM>. In this example, the first fault is an unintended or unintentional conductive event where current is conducted out of the set of primary windings <NUM>, which is shown reaching the shielding layer <NUM>. In one non-limiting example, this first fault <NUM> could be caused by a breakdown of an insulating layer of the set of primary windings <NUM>, core <NUM>, or the like. In this example, the shielding layer <NUM> will have a voltage level closer to the voltage at the set of primary windings <NUM>, but the shielding layer <NUM> will not have a voltage level of the predetermined voltage. As previously described, the voltage level of the shielding layer <NUM> can be delivered to the controller module <NUM> by way of the voltage signal <NUM>.

The controller module <NUM> can further be configured to compare the detected or sensed voltage from the voltage signal <NUM> with the predetermined voltage. Upon determining the detected or sensed voltage of the voltage signal <NUM> is not equal to the predetermined voltage (e.g. due to the presence of the first fault <NUM>) or sufficiently beyond a comparison threshold with the predetermined voltage (e.g. greater than <NUM> volt difference from the predetermined voltage), determine an electrical fault has or is likely occurred, and controllably disable the circuit <NUM>, the electromagnetic device <NUM>, or the like. For example, upon determining an electrical fault is or has occurred, the controller module <NUM> can effect, disable, or operably cease the supply of power to the set of primary windings <NUM> from the power source <NUM>, for instance, by way of the control signal <NUM> controlling the input filtering and switching circuit <NUM>. In another non-limiting example, the controller module <NUM> can further or alternatively notify another system of the actual or suspected electrical fault, log and error, provide an alert, or the like.

Similarly, an example second fault <NUM> is illustrated, demonstrating a schematic electrical fault between the set of secondary windings <NUM> and the shielding layer <NUM>, which will cause the shielding layer <NUM> to have a voltage level closer to the voltage at the set of secondary windings <NUM>, compared with the predetermined voltage. Additionally, an example third fault <NUM> is shown demonstrating a schematic electrical fault between the shielding layer <NUM> and an electrical ground <NUM> (or another referential voltage level). In any set or subset of these electrical faults <NUM>, <NUM>, <NUM>, the voltage signal <NUM> will provide the controller module <NUM> a sensed or detected voltage value different from the predetermined voltage, indicative of the electrical fault <NUM>, <NUM>, <NUM>. Non-limiting examples of the disclosure can be included wherein, for example, the controller module <NUM> can further determine which components are included in the electrical fault, for example, by way of distinguishing the sensed or measured voltage level of the voltage signal <NUM>. For example, a voltage signal <NUM> at or near the power source <NUM> voltage can indicate the first fault, a voltage signal <NUM> at or near the set of secondary windings <NUM> voltage can indicate the second fault <NUM>, and a voltage signal <NUM> at or near electrical ground <NUM> voltage can indicate the third fault <NUM>. The specific position of the faults <NUM>, <NUM>, <NUM> illustrated are merely non-limiting schematic examples of arcing events at the circuit <NUM>, electromagnetic device <NUM>, or the transformer <NUM>.

<FIG> illustrates one non-limiting perspective view of aspects of the disclosure. As shown, a circuit <NUM> or transformer <NUM> can be included. The circuit <NUM> or transformer <NUM> is similar to the circuit <NUM> or transformer <NUM>; therefore, like parts will be identified with like numerals increased by <NUM>, with it being understood that the description of the like parts of the circuit <NUM> or transformer <NUM> applies to the circuit <NUM> or transformer <NUM>, unless otherwise noted. One difference is that the transformer <NUM> includes a magnetically permeable core <NUM>, shown as a core <NUM> including a first core segment <NUM> spaced from a second core segment <NUM>.

At least two sets of windings <NUM>, such as conductive coils <NUM>, can be wound, wrapped, or otherwise formed about a former <NUM>. The former <NUM> can further be carried across a center leg <NUM> of each of the first and second core segments <NUM>, <NUM>. Additionally, the former <NUM> can include axially spaced caps <NUM> positioned opposite each other in a direction between the first core segment <NUM> and the second core segment <NUM>. The former <NUM> and caps <NUM> can comprise a non-conductive material, such as plastic, thermally conductive plastic, or a composite.

As described the at least two sets of windings <NUM> or conductive coils <NUM> can be circumferentially wound relative to the former <NUM>, as well as relative to windings <NUM>, themselves. For example, a first set of windings, such as the primary windings can be wound about the former <NUM> first, and thus be positioned closer to the radial center of the former <NUM>, which can then be overlapped by a second set of windings. As previously described, each winding of the at least two sets of windings <NUM> or each coil, wire, or the like of the conductive coils <NUM> can be layer, wrapped, or otherwise insulated from adjacent windings or coils by way of an non-conductive insulating layer.

The first core segment <NUM> and second core segment <NUM>, the former <NUM>, and the at least two sets of windings <NUM> can be mounted to a common structure, shown schematically as a mounting bracket <NUM>.

The circuit <NUM> or transformer <NUM> can further be seen in <FIG>, which is a cross-sectional view of the circuit <NUM> taken along line IV-IV of <FIG>. The view of <FIG> is represented schematically for ease of understanding. As better shown in <FIG>, the structure of the former <NUM> and wrapping of the at least two sets of windings <NUM>, <NUM> can include the center leg <NUM> in the radial center of the former <NUM>. The first radial layer can include the set of primary windings <NUM>, which can be similar to the set of primary windings <NUM> of <FIG> and <FIG>. Overlying or enveloping the set of primary windings <NUM> is a non-conductive insulation layer <NUM>, which for example can be wrapped about the set of primary windings <NUM> to further ensure no conductive contact of the conductive windings is exposed.

The non-conductive insulation layer <NUM> covering the set of primary windings <NUM> can then be overlaid or enveloped with a shielding layer <NUM>, such as the shielding layer <NUM> schematically represented in <FIG> and <FIG>. The shielding layer <NUM> can further be overlaid or enveloped with another non-conductive insulation layer <NUM>. Overlaying or enveloping the insulation layer <NUM> outside of the shielding layer <NUM> can be another set of conductive windings, such as a set of secondary windings <NUM> which can be similar to the set of secondary windings <NUM> of <FIG> and <FIG>. The set of secondary windings <NUM> can further be optionally overlaid or enveloped with, respectively, a non-conductive insulation layer <NUM> followed by another shielding layer <NUM>.

While multiple insulation layers <NUM> are shown, aspects of the disclosure can include additional or fewer insulation layers <NUM> between or isolating conductive layers <NUM>, <NUM>, <NUM> from one another. Furthermore, while the set of insulation layers <NUM> are all schematically illustrated with a similar cross section, independent insulation layer <NUM> can comprise different or dissimilar dielectric or non-conductive materials. For example, a first insulation layer <NUM> can include a non-conductive potting compound while a second insulating layer <NUM> can include a non-conductive wrap of composite, paper, plastic, or the like. In another non-limiting example, each of the caps <NUM> can further include an axial-facing shielding layer <NUM> between the respective sets of windings <NUM>, <NUM> and the caps <NUM>.

While a specific and separate insulating layer <NUM> is shown, non-limiting example of the disclosure can include any sort of insulating layer or electrical insulation between respective layers. For example, the insulating layer <NUM> can include an incomplete or non-uniform layer, such as insulating tape, an insulative coating disposed on one of the separated conductive layers (e.g. the set of primary windings <NUM>, the set of secondary windings <NUM>, or the shielding layer <NUM>), or a combination thereof. In another example, the insulation layer(s) <NUM> can include another non-electrically conductive thermally conductive potting or insulation material.

During operation, the set of primary windings <NUM> can be connected with a voltage source, such as the power source <NUM> of <FIG> and <FIG>. The voltage is ultimately delivered to the set of primary windings <NUM>, whereby an induced voltage is generated in the set of secondary windings <NUM>, which is further provided to, for example, the power output <NUM> of <FIG> and <FIG>.

In the event that an electrical isolation layer or non-conductive layer of the sets of windings <NUM>, <NUM> breaks down, is worn down, is damaged, or the like, or in the event that one of the insulating layers <NUM> breaks down, is worn down, is damaged, or the like, a conductive contacting event, arcing event, or electrical fault event (such as the first, second, or third faults <NUM>, <NUM>, <NUM> of <FIG>) can result in a voltage being applied to at least one of the shielding layers <NUM>. The difference in voltage at the respective shielding layer <NUM> is detected by the controller module <NUM>, which responds by operating the circuit <NUM>, <NUM> or transformer <NUM>, <NUM>, as needed.

Thus the arrangement of the shielding layer <NUM> disposed between conductive sets of windings <NUM>, <NUM> can detect electrical faults. Furthermore, the arrangement of the shielding layer <NUM> disposed outside or external to the sets of windings <NUM>, <NUM> (e.g. the most radially distal shielding layer <NUM>) can further detect electrical faults that would otherwise be directed external to the transformer <NUM>. In yet another non-limiting example, the axial-facing shielding layer <NUM> between the respective sets of windings <NUM>, <NUM> and the caps <NUM> can detect and axially-directed electrical faults. In yet another non-limiting example, a shielding layer <NUM> can be included between the first conductive set of windings <NUM> and the former <NUM> or the center leg <NUM>.

In yet another non-limiting example, while the schematic circuit <NUM> of <FIG> and <FIG> shows a voltage divider <NUM> having a single voltage output energizing the shielding layer <NUM>, aspects of the disclosure can be included wherein each respective shielding layer <NUM>, <NUM>, <NUM> (including different radially arranged shielding layers <NUM> of <FIG>) can be energized at a different voltage, and have an independent connection with the controller module <NUM> to provide an individual voltage signal <NUM>. In this sense, the controller module <NUM> can be configured or adapted to determine which shielding layer <NUM>, <NUM>, <NUM> is detecting an electrical fault based on the set of voltage signals <NUM>. Furthermore, the controller module <NUM> can be configured or adapted to determine which electrical source of the electrical fault (e.g. the set of primary windings <NUM>, <NUM>, the set of secondary windings <NUM>, <NUM>, an electrical ground <NUM>, or the like) is causing the fault, based on the sensed or measured voltage signal <NUM>. Thus, the controller module <NUM> can be configured or adapted to identify which shielding layer <NUM>, <NUM>, <NUM> is detecting the electrical fault, and from what voltage source is the fault coming from. Such determinations can be useful in repair and diagnosis actions by maintenance personnel performing maintenance actions in response to the determination of an electrical fault by the controller module <NUM>.

Aspects of the disclosure can also include a method for of detecting a fault in a power transformer, as described herein. For example, the method can include a power transformer having an conductive shield layer <NUM>, <NUM> sandwiched between electrical insulating layers <NUM> separating the conductive shield layer <NUM>, <NUM> from a first conductor (such as the set of primary windings <NUM>, <NUM>) and a second conductor (such as the set of secondary windings <NUM>, <NUM>), the second conductor opposite the conductive shield layer <NUM>, <NUM> from the first conductor. The method can sense a voltage energizing the shield layer <NUM>, <NUM>, as described, and further compare the sensed voltage to a threshold voltage value corresponding to a fault, for example, in the controller module <NUM>. Upon satisfaction of the comparison, the method can provide a fault indication when the comparison indicates the presence of a fault. A fault indication can include logging an error in system, generating an alert message or an alert sound, scheduling a maintenance event or maintenance action, or the like. As used herein, a maintenance event or maintenance action can include scheduling an action to investigate, repair, replace, or otherwise provide or performing corrective actions in response to the indication of the presence of the fault.

The sequence described is for understanding purposes only and is not meant to limit the method in any way as it is understood that the portions of the method can proceed in a different logical order, additional or intervening portions can be included, or described portions of the method can be divided into multiple portions, or described portions of the method can be omitted without detracting from the described method. For example, the method can include ceasing transmission of any electrical signal passing through the power transformer <NUM>, <NUM> (e.g. by way of the controller module <NUM> or control signal <NUM> controlling the input filtering and switching circuit <NUM>) in response to the satisfaction of the comparison. In another example, the comparing can further include comparing the sensed voltage to a set of threshold voltage values including at least a first predetermined energization voltage of the set of primary windings <NUM>, <NUM> (for example, the voltage of the power source <NUM>) and a second predetermined energization voltage of the set of secondary windings <NUM>, <NUM> (for example, the voltage at the power output <NUM>), and determining a fault of the electrical insulator layers occurs upon satisfaction of the comparison.

In yet another non-limiting example, the method can further include determining a fault in the insulation layer <NUM> separating the conductive shield layer <NUM>, <NUM> from the set of primary windings <NUM>, <NUM> upon satisfaction of a comparison of the sensed voltage to the first predetermined energization voltage of the set of primary windings <NUM>, <NUM>, and determining a fault in the insulation layer <NUM> separating the conductive shield layer <NUM>, <NUM> from the set of secondary windings <NUM>, <NUM> upon satisfaction of a comparison of the sensed voltage to the second predetermined energization voltage of the set of secondary windings <NUM>, <NUM>. In yet another non-limiting example, the set of threshold voltage values include a grounded voltage value (e.g. at an Earth ground <NUM> or relative ground value), and determining a grounding fault of the electrical insulator layers <NUM> occurs upon satisfaction of the comparison.

Many other possible aspects and configurations in addition to that shown in the above figures are contemplated by aspects of the disclosure. For example, while radially arranged windings <NUM>, <NUM> are described and illustrated, additional configurations of power transformers for switched mode power supplies can be included. For instance, a set of primary windings can be axially spaced along the former <NUM> (or center leg <NUM> length) from a set of secondary windings, and wherein the electrical shielding layer(s) (including isolating non-conductive insulation layers) can ensure an axial barrier between the axially spaced windings detects or sensing faults. In the instance the axial barrier includes a non-conductive barrier, such as a portion of the former <NUM> itself (e.g. similar to a cap-like structure), additional electrical shielding layer(s) can be included, similar to the axial-facing shielding layers <NUM> described herein. Additionally, the design and placement of the various components can be rearranged such that a number of different in-line configurations could be realized.

The aspects disclosed herein provide a method and circuit for detecting an arc fault occurrence. The technical effect is that the above described aspects enable the operation of the circuit allowing or enabling the detecting of one or more arc faults in an electrical circuit, such as in a transformer. One advantage that can be realized in the above aspects of the disclosure is that the detection and extinguishing of arc faults (for example, by operating the input filtering and switching circuit <NUM>) can limit damage of an energy escape during the arcing event.

Power converters in such architectures, such as transformers, need to mitigate against the failure of electrical isolation components. Aspects of the disclosure described herein use a shielding layer about, inside, and proximate to the main transformer (or windings thereof) to prevent breakdown of the primary windings to the secondary windings, or to a grounding or another conductive connection, and provides improved product and hence aircraft safety. Transformers in particular are susceptible to breakdown or partial discharge due to the minimal insulation thickness, which is typically minimized in order to maximize transformer power density.

To the extent not already described, the different features and structures of the various aspects can be used in combination with each other as desired. That one feature cannot be illustrated in all of the aspects is not meant to be construed that it cannot be, but is done for brevity of description. Thus, the various features of the different aspects can be mixed and matched as desired to form new aspects, whether or not the new aspects are expressly described. Combinations or permutations of features described herein are covered by this disclosure.

Claim 1:
An electrical fault detecting circuit (<NUM>, <NUM>) for detecting a fault in a power transformer (<NUM>, <NUM>), the electrical fault detecting circuit (<NUM>, <NUM>) comprising:
a first conductor wound about a permeable magnetic core;
a second conductor wound about the permeable magnetic core;
a plurality of electrical insulating layers (<NUM>);
a conductive shield layer (<NUM>) sandwiched between electrical insulating layers (<NUM>) separating the conductive shield layer (<NUM>) from the first conductor and the second conductor, wherein the second conductor is arranged opposite the conductive shield layer (<NUM>) from the first conductor;
a voltage output arranged to energize the shield layer (<NUM>) to a predetermined voltage; characterized by the electrical fault detecting circuit further comprising:
a controller module (<NUM>) arranged to sense an actual voltage energizing the shield layer (<NUM>), compare the sensed voltage to a threshold voltage value corresponding to a fault, and upon satisfaction of the comparison, provide a fault indication when the comparison indicates the presence of a fault.