초록 ▼

In various embodiments, an electrical heating assembly is disclosed. The electrical heating assembly comprises one or more electrical heating elements. A current leakage sensor is operatively coupled to the one or more heating elements. The current leakage generates a signal indicative of current le

In various embodiments, an electrical heating assembly is disclosed. The electrical heating assembly comprises one or more electrical heating elements. A current leakage sensor is operatively coupled to the one or more heating elements. The current leakage generates a signal indicative of current leakage from the electrical heating elements. The current leakage is proportional to an amount of moisture in contact with the electrical heating elements. A thyristor is coupled to the electrical heating elements. The thyristor is configured to control a power level of the one or more heating elements. A control logic is coupled to the thyristor and the leakage circuit. The control logic is configured to activate the one or more heating elements in a dry-out mode and a control mode. The control logic switches from the dry-out mode to the control mode when the signal indicative of the current leakage is below a predetermined threshold.

대표청구항 ▼

1. An electrical heating assembly comprising: one or more medium voltage electrical heating elements that are configured to receive power from a medium voltage power source that supplies between 600 and 38,000 volts to the one or more medium voltage electrical heating elements, wherein the one or mo

1. An electrical heating assembly comprising: one or more medium voltage electrical heating elements that are configured to receive power from a medium voltage power source that supplies between 600 and 38,000 volts to the one or more medium voltage electrical heating elements, wherein the one or more medium voltage electrical heating elements each comprises: an outer metal sheath;a resistive wire; anda dual dielectric core positioned within the outer metal sheath, wherein the dual dielectric core comprises: a first series of two or more axially-aligned outer tubular dielectric bodies positioned end-to-end, wherein the first series of two or more axially-aligned outer tubular dielectric bodies define a central longitudinal opening and have a first longitudinal axis; anda second series of two or more axially-aligned inner tubular dielectric bodies having a second longitudinal axis, wherein: the second series of two or more axially-aligned inner tubular dielectric bodies are positioned end-to-end in the outer metal sheath and are nested at least partially within the central longitudinal opening inside the first series of two or more axially-aligned outer tubular dielectric bodies;the first longitudinal axis is co-axial with the second longitudinal axis;the second series of two or more axially-aligned inner tubular dielectric bodies define an interior passageway and the resistive wire is positioned in the interior passageway; andthe second series of two or more axially-aligned inner tubular dielectric bodies are longitudinally staggered relative to the first series of two or more axially-aligned outer tubular dielectric bodies;a current leakage sensor configured to generate a signal indicative of current leakage from the one or more medium voltage electrical heating elements, wherein the current leakage is proportional to an amount of moisture in contact with the one or more medium voltage electrical heating elements, and wherein the signal is a vector sum of a current flowing through the one or more medium voltage electrical heating elements;a thyristor coupled to the one or more medium voltage electrical heating elements, wherein the thyristor is configured to control a power level of the one or more medium voltage electrical heating elements; anda control logic circuit coupled to the thyristor and the current leakage sensor, wherein the control logic circuit is configured to control the one or more medium voltage electrical heating elements and the thyristor based on the signal indicative of the current leakage from the one or more medium voltage electrical heating elements sensed by the current leakage sensor, and wherein the control logic circuit is configured to maintain the one or more medium voltage electrical heating elements at a first power level, in a dry-out mode, while the current leakage detected by the current leakage sensor is proportional to an unacceptable range of moisture in contact with the one or more medium voltage electrical heating elements. 2. The electrical heating assembly of claim 1, wherein the control logic circuit operates the one or more medium voltage electrical heating elements in a control mode when the signal indicative of the current leakage is below a predetermined threshold. 3. The electrical heating assembly of claim 2, wherein the dry-out mode comprises the control logic circuit simultaneously operating the one or more medium voltage electrical heating elements at the first power level. 4. The electrical heating assembly of claim 3, wherein the first power level comprises 5-10% of a maximum power level of the electrical heating assembly. 5. The electrical heating assembly of claim 2, wherein, in the dry-out mode, the control logic circuit sequentially operates the one or more medium voltage electrical heating elements at the first power level. 6. The electrical heating assembly of claim 5, wherein the first power level comprises 100% of a maximum power level of the electrical heating assembly. 7. The electrical heating assembly of claim 2, wherein the thyristor comprises a silicon controlled rectifier. 8. The electrical heating assembly of claim 2, wherein: the one or more medium voltage electrical heating elements comprises a plurality of medium voltage electrical heating elements, andthe electrical heating assembly further comprises: a plurality of primary contactors, wherein each one of the plurality of primary contactors is coupled to one of the medium voltage electrical heating elements; anda plurality of secondary contactors, wherein each one of the plurality of secondary contactors is coupled to one of the plurality of medium voltage electrical heating elements. 9. The electrical heating assembly of claim 8, wherein the control logic circuit closes at least one of the plurality of primary contactors and the plurality of secondary contactors to activate the dry-out mode. 10. The electrical heating assembly of claim 8, wherein the control logic circuit closes one of the plurality of primary contactors and one of the plurality of secondary contactors to activate the dry-out mode for one of the one or more medium voltage electrical heating elements. 11. A method for drying a medium voltage electrical heating element, the method comprising: activating, by a control logic circuit, one or more medium voltage electrical heating elements at a first power level, wherein the one or more medium voltage electrical heating elements receive power from a medium voltage power source that supplies between 600 and 38,000 volts to the one or more medium voltage electrical heating elements wherein the one or more medium voltage electrical heating elements each comprise: an outer metal sheath;a resistive wire; anda dual dielectric core positioned within the outer metal sheath, wherein the dual dielectric core comprises: a first series of two or more axially-aligned outer tubular dielectric bodies positioned end-to-end, wherein the first series of two or more axially-aligned outer tubular dielectric bodies define a central longitudinal opening and have a first longitudinal axis; anda second series of two or more axially-aligned inner tubular dielectric bodies having a second longitudinal axis, wherein: the second series of two or more axially-aligned inner tubular dielectric bodies are positioned end-to-end in the sheath and are nested at least partially within the central longitudinal opening inside the first series of two or more axially-aligned outer tubular dielectric bodies;the first longitudinal axis is co-axial with the second longitudinal axis;the second series of two or more axially-aligned inner tubular dielectric bodies define an interior passageway and the resistive wire is positioned in the interior passageway; andthe second series of two or more axially-aligned inner tubular dielectric bodies are longitudinally staggered relative to the first series of two or more axially-aligned outer tubular dielectric bodies;detecting, by a current leakage sensor, a current leakage of the one or more medium voltage electrical heating elements wherein the current leakage is proportional to an amount of moisture in contact with the one or more medium voltage electrical heating elements and wherein the current leakage is detected as a vector sum of a current flowing through the one or more medium voltage electrical heating elements; andmaintaining, by the control logic circuit, the one or more medium voltage electrical heating elements at the first power level, wherein the control logic circuit maintains the one or more medium voltage electrical heating elements at the first power level while the current leakage detected by the current leakage sensor is proportional to an unacceptable range of moisture in contact with the one or more medium voltage electrical heating elements. 12. The method of claim 11, wherein activating the one or more medium voltage electrical heating elements comprises activating, by the control logic circuit, the one or more medium voltage electrical heating elements simultaneously at the first power level. 13. The method of 11, wherein activating the one or more medium voltage electrical heating elements comprises: activating, by the control logic circuit, the one or more medium voltage electrical heating elements sequentially at the first power level in response to the current leakage detected by the current leakage sensor. 14. The method of claim 13, wherein the first power level comprises 100% of a maximum power level of the one or more medium voltage electrical heating elements. 15. The method of claim 11, wherein activating and maintaining the one or more medium voltage electrical heating elements at the first power level comprises controlling, by the control logic circuit, a first plurality of contactors and a second plurality of contactors that are connected to the one or more medium voltage electrical heating elements. 16. The method of claim 15, wherein activating the one or more medium voltage electrical heating elements comprises activating, by the control logic circuit, at least one of the first plurality of contactors and at least one of the second plurality of contactors to activate one of the one or more medium voltage electrical heating elements. 17. The electrical heating assembly of claim 1, wherein the control logic circuit monitors the signal indicative of the current leakage from the one or more medium voltage electrical heating elements and stores historic data associated with the signal indicative of the current leakage in a computer-readable storage medium. 18. The method of claim 11, further comprising: monitoring, by the control logic circuit, the detected current leakage by the current leakage sensor of the one or more medium voltage electrical heating elements; andstoring, by the control logic circuit, historic current leakage data for the one or more medium voltage electrical heating elements in a computer-readable storage medium. 19. The method of claim 18, further comprising: storing, by the control logic circuit, additional data in the computer-readable storage with the historic current leakage data, wherein the additional data comprises one or more of: data indicative of which of the one or more medium voltage electrical heating elements produced the current leakage;a power level of the heating element that produced the leakage current; andan operational mode of the one or more medium voltage electrical heating elements that produced the leakage current.