Abstract: An isolator surge protector (ISP) is provided which blocks DC current and passes AC current and AC and DC fault currents. The ISP includes a main bypass path, including main bypass path switching devices, that is connected in parallel with a DC blocking capacitor. Primary triggering of the main bypass path switching devices occurs when the voltage across the ISP exceeds a primary voltage trigger level. Repeated triggering of the bypass path switching devices, and high current discharge of the high voltage DC blocking capacitor through the bypass path, under abnormal steady state voltage conditions, is prevented by initiating a secondary triggering period following primary triggering of the bypass path switching devices. During the extended secondary triggering period, triggering of the bypass path switching devices occurs at a low secondary voltage trigger level.

Abstract: A high power DC blocking device is provided which blocks DC current, passes AC current, and limits the voltage across it under fault conditions. A DC blocking capacitor is used to block the flow of DC current, while allowing the passage of normal AC currents. A main bypass path includes switching devices which provide a low impedance path across the capacitor under fault conditions. Auxiliary switching devices are used to connect a storage capacitor across the device at the initiation of a fault, thereby charging the storage capacitor to a stored voltage level before the main switching devices are fired. After the fault passes, the auxiliary switching devices are fired once again to apply the stored voltage in the storage capacitor to the main switching devices to commutate them off. The storage capacitor and auxiliary switching devices also form part of a voltage clamp circuit which dissipates inductive energy stored in a system to which the DC blocking device is connected.

Abstract: An electrical isolation device is connected at input terminals in lines between a structure to be cathodically protected and a ground, or between two cathodically protected structures, to block selected low levels of DC voltage while freely conducting normal AC currents and all fault currents. The device has two diode stacks, formed of layers, and the stacks are connected in parallel with one another in opposite polarity and in parallel with a capacitor across the input terminals of the device. Each diode layer include a junction wafer and a conducting metal disk. The layers in each stack are preferably pressed tightly together and to metal bus conductors by a clamp to maximize the contact of the diode layers to each other and to the conductors to minimize contact resistance. AC currents are conducted (e.g., to ground) through the capacitor while low level DC voltages are blocked by the cumulative threshold voltages of the plural diode layers connected in series in each of the stacks.

Abstract: An isolator surge protector for use with corrosion protection systems which are an inherent part of or coupled to an electrical power system, for power transformers, and for DC transmission systems, where it is necessary to present a high impedance to DC and a low impedance to AC up to a predetermined voltage level. Anti-paralleled thyristors in the isolator surge protector turn on during power surges. A bypass circuit insures turn off of the thyristors after a triggering event such as lightning or a 60 Hz surge has ended. The bypass circuit shunts DC bias currents, such as that which may be provided by a DC bias voltage source for cathodic protection, from the thyristors to ensure that the voltage across each thyristor falls below its holding voltage or current, and thus prevents the thyristor from being stuck in a continuous conduction mode. Power to operate the bypass circuit may be tapped from the surge which caused the thyristor to trigger so that the bypass circuit operates autonomously.

Abstract: A connector module for loadbreak operation having an insulating housing and a switch insert. The insert includes a container with a major portion of uniform diameter and a configuration such that the diameter does not increase from its outer end to its inner end, to permit the insert to be installed in the finished housing. Inside the container is a snuffer-contact assembly which has a bore lined with an ablative material. A bore contact having a gas port is attached to a snuffer tube of the assembly and has fixed to it a piston adapter for driving the snuffer-contact assembly toward the open end of the container tube in response to gas generated by arcing inside the bore. Resilient sliding contact means are fixed to the piston and press against the inside wall of the container tube to establish continuous electrical contact with it even while the piston is moving.

Abstract: A connector module for loadbreak operation having an insulating housing and a switch insert. The insert includes a container with a major portion of uniform diameter and a configuration such that the diameter does not increase from its outer end to its inner end. Inside the container is a snuffer-contact assembly. A bore contact having a gas port is attached to a snuffer tube of the assembly and has fixed to it a piston adapter for driving the snuffer-contact assembly toward the open end of the container tube in response to gas generated by arcing inside the bore. Resilient sliding contact means are fixed to the piston and press against the inside wall of the container tube to establish continuous electrical contact with it even while the piston is moving. A gas check valve member is resiliently seated against the inner side of the gas port. Keyways in the piston ride over longitudinal keyribs formed in the wall of the container to prevent rotation of the piston in the container.

Abstract: A connector module for loadbreak operation having an insulating housing and a switch insert. The insert includes a container with a major portion of uniform diameter and a configuration such that the diameter does not increase from its outer end to its inner end, to permit the insert to be installed in the finished housing. Inside the container is a snuffer-contact assembly which has a bore lined with an ablative material. A bore contact having a gas port is attached to a snuffer tube of the assembly and has fixed to it a piston adapter for driving the snuffer-contact assembly toward the open end of the container tube in response to gas generated by arcing inside the bore. Resilient sliding contact means are fixed to the piston and press against the inside wall of the container tube to establish continuous electrical contact with it even while the piston is moving.

Abstract: A rod connector module of the type comprising an insulating housing containing a contact rod support, a receiving cone in the housing extending from the exterior toward the support, and a conductive contact rod fixed at one end to the support and extending toward the exterior along the axis of the well is provided with a layer of electrically resistive voltage stress grading material of the inside surface of the well and electrically connected to the supported end of the rod.

Abstract: A shielded cable separable connector module is of the type having a contact assembly inside an insulating housing of elastomeric material. The housing includes a mating portion having a configuration suited for intimate engagement with a corresponding mating portion of a matching second module for establishing contact with the contact assembly of the second module. The improvement comprises a coating of phenolic resin-bonded polytetraflouroethylene solid film lubricant on the surface of at least the mating portion of the first module housing. A silicone grease may be used in addition to the solid film lubricant coating, if desired.