摘要:
A method for rejuvenating a strand-blocked cable having a conductor comprised of a plurality of conductor strands with interstitial volume therebetween blocked by a PIB based mastic, the conductor being surrounded by a polymeric cable insulation. The method comprising installing injection adapters that seal the cable ends of the cable and are usable to inject fluid into the interstitial volume between the conductor strands of the cable; elastically expanding the polymeric cable insulation through the application of pressure to the interstitial volume between the conductor strands of the cable; and injecting at least one injection fluid in which the PIB based mastic is mostly insoluble into the interstitial volume between the conductor strands of the cable.
摘要:
A system including an active ventilation device and a system controller. The active ventilation device is installed in an underground vault and generates an exhaust flow from the vault having an exhaust rate. The system controller is configured to determine that a reading received from a selected gas sensor indicates that a manhole event is occurring, and instruct the active ventilation device to change the exhaust rate when the reading indicates that the manhole event is occurring. The system controller is configured to receive at least one sensor reading after the exhaust rate has been changed, determine whether the selected gas sensor is exhibiting drift based at least in part on the sensor reading(s), and perform an action when the system controller determines the selected gas sensor is not exhibiting drift. The action includes notifying a user and/or instructing the active ventilation device to alter the exhaust rate.
摘要:
Provided are methods for extending the life of in-service electrical cable having polymeric insulation, comprising injecting into the cable a dielectric gel formulation containing: (a) Si—H endblocked polydiorganosiloxane (H(R2SiO)x(R2Si)H); (b) polydiorganosiloxane endblocked with unsaturated carbon-carbon functionality; (c) hydrosilylation catalyst suitable to cure (a) and (b); and (d) at least one organoalkoxysilane functional additive (e.g., anti-oxidant-based alkoxysilane, voltage stabilizer-based alkoxysilane, hindered amine light stabilizer (HALS)-based alkoxylsilane, UV absorber-based alkoxysilane, etc.), wherein (a) and (b) are cured post-injection into a non-flowable gel, and wherein (d) diffuses into the insulation. The methods may further comprise a hydrolysis/condensation catalyst compatible with the hydrosilylation catalyst so as not to interfere with the cure of (a), (b) and (c), and/or be compatible with optional siloxane crosslinkers, and/or with optional hydrosilylation inhibitors.
摘要:
A dielectric enhancement fluid composition having at least one organoalkoxysilane and an acid catalyst having a pKA less than about 2.1 and a method for using the composition to enhance the dielectric properties of an electrical cable having a central stranded conductor encased in a polymeric insulation and having an interstitial void volume in the region of the conductor, the method comprising at least partially filling the interstitial void volume of the cable with the composition. The fluid composition may further include an organometallic catalyst and a corrosion inhibitor.
摘要:
A computer simulation method is disclosed for simulating an electrical cable having a stranded conductor surrounded by a conductor shield encased in an insulation jacket and having an interstitial void volume in the region of the conductor injected with a fluid composition comprising at least one dielectric enhancement fluid component so as to at least partially fill the interstitial void volume at an initial time. The simulation method comprises for a selected length of the simulated cable, defining a plurality of radially arranged finite volumes extending the selected length of the simulated cable, and estimating the radial temperature of each finite volume. For a selected time period after the initial time, performing a series of steps at least once and outputting or otherwise using the value of the new concentration for the dielectric enhancement fluid component within each finite volume.
摘要:
A method for selecting components for a mixture to be injected into an interstitial void volume adjacent to a central stranded conductor of an electrical cable segment having the central conductor encased in a polymeric insulation jacket to enhance the dielectric properties of the cable segment. The method includes selecting an anticipated operating temperature for the cable segment to be used in selecting the components for the mixture to be injected into the interstitial void volume of the cable segment and selecting a minimum desired time period to be used in selecting the compounds for the mixture to be injected during which the dielectric properties of the cable segment are to be enhanced by the mixture. Next, first, second and third components for the mixture are selected to provide the cable segment with a reliable life at the selected operating temperature spanning first, second and third time periods, respectively.
摘要:
An improved method for imparting excellent long-term dielectric performance to an in-service electrical cable section having a stranded conductor surrounded by a conductor shield encased in a polymeric insulation and having an interstitial void volume in the region of the conductor, the cable section having an average operating temperature T. The method comprising injecting a dielectric enhancement fluid composition into the interstitial void volume, the composition comprising at least one component selected from: (1) a water-reactive material selected from an organosilane monomer, the above organosilane monomer wherein at least one of the water-reactive groups has been substituted with a condensable silanol group, an oligomer oligomer of the above organosilane monomer, or a co-oligomer of the above organosilane monomer, the organosilane monomer having a diffusion coefficient at least about 15 times greater than the diffusion coefficient of its corresponding tetramer; (2) a water-reactive material similar to (1) having at least one group attached to silicon comprising 7 to about 20 —CH2— units; (3) a non-water-reactive organic material which has a diffusion coefficient of less than about 10−9 cm2/sec and an equilibrium concentration of at least about 0.005 gm/cm3 in the polymeric insulation, the above mentioned diffusion coefficients and equilibrium concentration being determined at temperature T; or (4) an organic compound having an equilibrium concentration in the polymeric insulation at 55° C. which is less than 2.25 times the equilibrium concentration at 22° C.
摘要:
A method for extending the useful life of an in-service electrical cable section having at least two existing connectors attached thereto and a conductor surrounded by a conductor shield encased in a polymeric insulation jacket with an interstitial void volume in the region of the conductor. The method includes replacing each connector with a corresponding high-pressure connector, and injecting a dielectric enhancement fluid into the void volume and confining the fluid therein at a pressure sufficient to introduce at least about 0.75Q of the fluid. Wherein Q represents the weight of the fluid which would saturate the conductor shield and insulation jacket, and the void volume at atmospheric pressure being less than that which would accommodate the amount 0.75Q. The method is carried out using only a single switching cycle.
摘要:
A method for selecting components for a mixture to be injected into an interstitial void volume adjacent to a central stranded conductor of an electrical cable segment having the central conductor encased in a polymeric insulation jacket to enhance the dielectric properties of the cable segment. The method includes selecting an anticipated operating temperature for the cable segment to be used in selecting the components for the mixture to be injected into the interstitial void volume of the cable segment and selecting a minimum desired time period to be used in selecting the compounds for the mixture to be injected during which the dielectric properties of the cable segment are to be enhanced by the mixture. Next, first, second and third components for the mixture are selected to provide the cable segment with a reliable life at the selected operating temperature spanning first, second and third time periods, respectively.
摘要:
A high-pressure connector for an electrical power cable segment having a central stranded conductor encased in a polymeric insulation jacket with an interstitial void volume in the region of the conductor. The connector confines a fluid within the interstitial void volume at a residual pressure above atmospheric, but below the elastic limit of the insulation jacket. A housing interior chamber receives the conductor in fluid communication with the interstitial void volume. Some embodiments have the chamber sized to receive and overlap a portion of the insulation jacket with a housing end portion swaged thereto. A seal seals the insulation jacket with respect to the housing and a retaining member secures the cable segment to the housing to prevent pushback of the insulation jacket at the residual pressure.