S&c Electric Company

Thomas J Tobin

Leonard V Chabala

Raymond P O'Leary

Joel A Ramos

Otto Meister

Edward J Rogers

Raymond P O'leary

Christopher D Roman

Robert H Harner

John Haarsma

Michael G Ennis

Todd W Klippel

John A Zulaski

Walter J Hall

Peter J Meyer

Norman J Stranczek

Andrew D Pfister

Jeffrey A Moore

Mark W Stavnes

Hiram Solomon Jackson, Jr

Douglas M Staszesky

E William Schmunk

Harner Robert H

A method for determining an optimized TCC operating curve for an electronic interrupting device that protects a distribution transformer in a power distribution network, where the TCC operating curve is some optimized predetermined percentage above a TCC curve for normal transformer operation. The method includes providing a TCC transformer curve that identifies an allowed transformer operation current once the transformer magnetics have been stabilized and the transformer is operating normally, and determining a TCC operating curve that is defined by points along the transformer curve plus a predetermined percentage above the transformer curve, where the operating curve identifies a response time for when the electronic interrupting device will open in response to a certain current flow.

Optimized transformer protection

A fault detection system that that prevents a recloser from reclosing if a fault is determined to be internal to a transformer, where the recloser is configured to perform a reclosing operation in response to detecting overcurrent. The recloser includes a sensor, such as a light sensor, directed towards the transformer and detecting a fault event. If the recloser detects overcurrent, but the sensor does not detect the fault event, it is assumed that the fault is internal to the transformer and the recloser is prevented from reclosing.

Transformer internal fault reclose block

A fault detection system that includes a recloser configured to perform a reclosing operation in response to detecting overcurrent, where the recloser includes a communications device for receiving communications signals. The system also includes a transformer having an outer can, a sensor mounted to the can and extending into the can for measuring pressure therein, where the sensor includes a mechanical indicator that extends when overpressure is detected. The transformer further includes a radio mounted to the can and coupled to the sensor, where the radio includes a switch coupled to the mechanical indicator and a transmitter. When the mechanical indicator extends in response to detecting overpressure in the can it causes the switch to close which causes the transmitter to send a signal that is received by the communications device, which prevents the recloser from reclosing.

Transformer protector with internal fault detector

Described are curve shapes that may be implemented in a transformer protector that provide enhanced fault protection. A transformer protector curve rating structure relates response curves to the transformer size and simplifies selection of response curves implemented within a transformer protector and associated transformer.

Fault protection configuration for a resettable transformer protector

A fault protection system for an electrical power distribution system and a method of configuring and operating a fault protection system for an electrical power distribution system accepts device fault protection parameters, such as the time-current-characteristics (TCC's), of boundary devices, and selects and sets fault protection parameters for one or more fault protection devices, such as fault-interrupters, that thus coordinate with the boundary devices. Fault protection parameter selection for each fault protection device may occur automatically, and each device may reconfigure its fault protection parameters based upon changes in the electrical power distribution system, for example, as the result of fault isolation and/or service restoration.

Fault protection system and method for an electrical power distribution system

A current sensor for installation on a conductor without breaking the conductor may include an insulating base having a conductor supporting portion and a conductive coil disposed within an outer surface of the insulating base. A magnetically permeable conductor retaining member includes a portion that passes through the coil and is secured to the insulating base. The retaining member defines a conductor receiving aperture portion with the aperture portion being disposed adjacent the conductor supporting portion of the insulating base. With a conductor positioned within the aperture portion, the conductor is secured by the retaining member to the conductor receiving portion of the insulating base and a substantially continuous permeable path is formed by the conductor retaining member about the conductor.

Current sensor

A control method and arrangement is provided that monitors the condition and operating parameters of a power electronic system having power electronic devices to optimize operation of the power electronic system. Further, electrically isolated power supplies to individual control stages for high-voltage, series-connected switch devices/power electronic devices.

Control arrangement and isolated power supplies for power electronic system

An arc-quenching composition is provided including a filler, a fiber and a binder. Preferably, the filler includes an arc-quenching compound such as melamine. The binder includes a thermosetting resin to facilitate forming of the arc-quenching composition into an arc-quenching fuse tube. In a preferred arrangement, an outer tube is formed over the arc-quenching fuse tube to provide an overall high-strength fuse tube. Also in a preferred arrangement, in order to provide a fuse tube that is capable of operation over an extremely wide current range, the inner arc-quenching tube includes a tapered bore. According to one fabrication technique, the outer tube is formed over the arc-quenching inner tube before the curing of the inner tube such that a single structure results.

Fuse tube and method of manufacture thereof

A control arrangement and method is provided for source-transfer switching systems including a high-speed control arrangement and high-speed switches to control the transfer of a load from one source to another with minimal transfer delays. The system supplies an electrical load with alternating current from either a first source or a second source via respective first and second switches. The system also includes a controller that samples the voltage waveforms of each of the first and second sources to detect when transfer between the sources is desirable, e.g. power outages, voltage levels that are either too low or too high, or reverse currents that indicate an upstream fault. The controller provides appropriate control signals to control operation of the switches and transfer supply of the load therebetween. In a preferred embodiment, after a transfer decision is made, the control arrangement initiates a transfer of the load from a first source to a second source with no intentional delay via the opening of a first switch and the closing of a second switch. In another embodiment, the control arrangement initiates a transfer by first opening the first switch and then closing the second switch after the current is interrupted through the first switch. In yet another embodiment, transfer is accomplished via an 'open' transition, break before make, when severe disturbances of a first category are detected, and transfer is accomplished via a 'closed' transition, which may involve make-before-break conditions, when less severe disturbances of a second category are detected.

Source-transfer switching system and method

Method and apparatus are provided responsive to the circuit parameters at one or more locations of an electrical power transmission and/or distribution network for detecting protective device operation. The detection of the protective device operation is utilized to locate faults and also to ascertain the status of protective devices. This information is useful in automated power systems for desirable isolation and sectionalizing of faults for optimum restoration of the network. A fault detection unit of the present invention is responsive to sensed circuit parameters and provides at least first and second outputs indicative of protective device operations that open the circuit. The first output is provided upon the occurrence of an overcurrent followed by the loss of a circuit parameter, such as voltage, for a specified time duration. In a preferred arrangement, the timing for a specified time duration is started when the overcurrent ends. Thus, rapid detection is achieved since the specified time duration need not include the maximum operating time of the protective device. The second output is provided if the conditions for the first output are satisfied and the loss of the circuit parameter continues for a specified extended time interval corresponding to the sequence of operation of the upstream protective device so as to establish protective device operation. For example, the first output in one illustrative arrangement corresponds to the opening of a recloser while the second output corresponds to the lockout of the recloser. In a preferred arrangement, a third output is provided upon the occurrence of an overcurrent for a specified time duration. A fourth output is provided upon the occurrence of an overcurrent for a specified time duration and the presence of voltage after the occurrence of the first output for purposes of detecting downstream fuse operation on power systems utilizing fuse-saving arrangements.

Fault detection method and apparatus

A durable polymeric bearing is provided for a rotatable support insulator. The bearing is of sufficient conductivity to permit the flow of leakage current and capacitive charging current through the bearing. Thus, tracking across and/or deterioration of the bearing is avoided since insufficient voltage is developed across the bearing to cause any deleterious effects.

Support arrangement for a rotatable insulator

A multi-pole group-operated switch configuration is provided for electrical distribution circuits. The switch configuration includes integral arrangements for sensing circuit parameters and supplying power for a switch operator of the switch configuration. The switch configuration includes a plurality of switch-pole units. In accordance with desired characteristics and features, one or more of the switch-pole units includes an integral current-sensing device, an integral voltage-sensing device, or an integral combination voltage and current-sensing device. The voltage-sensing device also provides operating power to power a switch operator and charge the batteries of the switch configuration.

Switch configuration with integral sensing and power supply apparatus

A multi-pole group-operated switch is provided for electrical power distribution circuits. The switch is self-contained and suited for ease of use with various line spacings and arrangements of the distribution lines; e.g., side-by-side (horizontal plane), phase-over-phase, and cable drops. The switch includes a plurality of switch-pole units carried at desired spacings by a base support and drive arrangement. Each of the switch-pole units includes a housing, interrupting contacts, and disconnect contacts. The housing that encloses the interrupting contacts in movable to perform the disconnect function. The base support and drive arrangement encloses a high-speed interrupting linkage for operation of the interrupting contacts of each of the switch-pole units and carries an operating mechanism that is connected to the interrupting linkage internal to a base support member of the base support and drive arrangement. The switch also includes a disconnect linkage to move the switch-pole housings. For manual operation of the disconnect function, an operating handle is provided. The operating handle and the operating mechanism are oriented and positioned relative to the switch in various predetermined locations that are desirable for the particular mounting configuration of the switch with respect to the line layout and the equipment pole. In a preferred embodiment, the switch includes integral dead-ending connection provisions and also includes integral line- parameter sensing and power-supply provisions incorporated within one or more of the switch-pole units.

Self-contained switch for electrical distribution circuit

An arrangement for efficiently assembling and providing a plurality of circuit protection device configurations by use of major components that are common to the configurations and that are adapted for interconnection and functioning with each other; some of the major components providing different or multiple functions in the various configurations. The various configurations satisfy the application requirements and customer needs with regard to voltage rating, efficient space usage, station layouts, and the provision of disconnect mechanisms. The configurations include various orientations of interrupting units and the provision of various types of disconnect mechanisms. The major components include an operator, an interrupting unit, an insulating support column, and a base drive. The operator provides a first drive output and a second drive output. The insulating support column is capable of being rotated to provide a rotary drive output for disconnect mechanisms. The insulating support column also internally carries an operating member. The operating member is driven to operate the interrupting unit. The base drive is connected to receive the first drive output of the operator and in turn to provide a driving output to the operating member. The second drive output is connected through appropriate linkage to rotate the insulating support column.

Arrangement for providing various circuit protection device

An improved insulating material is provided. The insulating material is a mixture of an insulating fluid and solid insulative bodies. The insulating material exhibits desirable insulating, conformal coating, surface adhesion, and low-viscosity characteristics. For example, when the insulating material is used to fill the cavity of a hollow insulator, the insulating material prevents any moisture that enters the insulator from adhering to the walls that define the cavity; thus maintaining the insulating qualities of the insulator. In the event that some of the fluid is lost through leakage, the insulating material also aids in preserving the insulating qualities of the insulator.

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Northbrook, IL, United States of America

Thomas J Tobin