Search results for query: *

The short time rating for cable terminations (cold and heat shrink) is important to me as they are connected to an utility system with over 40 kA sym Amperes fault duty (both 3PH and SLG). Circuits leave Receiving Station Open-Air Rack via underground synthetic cables. We have to be really...

For outdoor cable terminations (cold or heat shrink) between extruded shielded cable and rigid-bus open-air rack - I have not been able to locate any specific short time withstand ratings supplied by vendors (such as 3M). Vendors do provide applicable BIL ratings. In addition, documentation...

The utility that I work uses single mode fiber optic cable between Receiving Stations for line differential protection. We have used both multi-plexed and point-to-point fiber optic circuits. Overall, the bandwidth requirements for tele-protection are extremely small compared to the...

I am an electrical engineer for a North American municipal electric utility. I am having a disagreement with my boss over the rating of a new medium voltage disconnect. Project details: - New disconnect to be installed in existing 35 kV open-air rack. - New disconnect will be used to open...

Yes, 34 kV over-built cable could have been laying across under-built 4 kV Circuit. The catch is that where the 34 kV over-built cable was laying on under-built 4 kV was approximately 1,000 feet from where all 3-phases of 4 kV circuit burned clear.

34 kV Over-Built Circuit was de-energized during this entire sequence of events on underbuilt 4 kV Circuit.

As follow-up, the 4 kV under-built circuit is all 336 AAC from substation to point at which over-built 34 kV bare conductor dropped. Distance from substation to location where 34 kV bare conductor dropped is approximately 3,000 feet. Distance from substation to where all 3 phases of 4 kV...

The electric utility I work for recently experienced a 4 kV Overhead Distribution Circuit line down, where all 3 phases of 4 kV circuit burned clear mid span. Span where 4 kV circuit burned clear had double-ended construction on both sides, so there was no significant tension on this span. All...

The utility I work for currently utilizes SKM PowerTools and Milsoft Engineering Analysis (EA) software. SKM PowerTools is used for short-circuit, load flow, and device coordination. Milsoft EA provides a GIS based model that can complete short-circuit and load flow based analysis. The device...

I am working on a 4.36 kV, 4-wire distribution circuit from a solidly-grounded delta-wye substation transformer with a connected load of 3,000 KVA. The connected load of 3,000 KVA is comprised of multiple 50 KVA 1-phase distribution transformers connected 2.4 kV L-to-G balanced across 3...

I have a cold load pickup (CLP) question related to a SEL-351R relay. SEL-351R relay protects a 4.36 kV 4-wire circuit with the following details: - Peak Phase Load : 280 Amps - 51P Pickup : 560 Amps Circuit recently tripped during peak conditions and was out-of-service for 2+ hours. SEL-351R...

I have an application involving a 1,200 foot run of OM4 laser optimized 50/125 um multi mode fiber optic cable. I have a new device that needs to communicate over this fiber link, but it only comes with a LED light source. Specs for new device are: Light Source: LED Data Rate: 100 Mbps...

At the utility where I work, a new 27 kV gas insulted switch with vacuum interrupters is exhibiting inconsistent test results across A, B, and C phases. Here are the test details as completed by utility: 1) All phases passed 1-Minute 40 kV AC Hi-Pot Testing. 2) B Phase exhibited a decrease in...

I am looking for any utility experience with installing overhead fault indicators on overhead primary tree wire. Overhead primary system is 4.36 kV, 4-wire and to date overhead fault indicators have only been installed on bare aluminum conductors. Tree wire is single layer w/ polyethylene...

I apologize for the lack of detail in my original post. Primary overhead system is 4-wire multi-grounded with a line-to-line voltage of 4.16 kV. Secondary voltage of 156 V was recorded at customer service panel. Upon inspection, it was noticed that the primary neutral connection to the...

What is the likely overvoltage that would result during a primary neutral break to an overhead single-phase distribution transformer rated 2.4 kV Line-to-Neutral that provides 120/240V three-wire secondary service? A secondary voltage of 156 V was measured on one of the secondary legs to ground.

I am working on a project focused on the detection of downed energized primary overhead lines to support wildfire mitigation on exposed feeders. Looking at the SEL-451 relay with Arc Sense Technology (AST) high-impedance fault detection. What other technologies / grounding should be considered...

The utility I work for just completed a Smart Grid Business Case. One of the identified benefits of the Smart Grid is having customers shift usage from on to off peak periods. For each KW of on peak demand shifted, consulant used a deferred T&D capital benefit of $685 / KW - Year based on a...

I have been asked to review proposed changes to the California Public Utilities Commission Feed-in-Tariff, specifically the allowable size of PV systems that can be interconnected to distribution systems. Note that these proposed changes are under consideration as a result of increasing the...

Related to electric utility Advanced Metering Infrastructure (AMI) projects, whereby revenue meters communicate to the utility via a wireless RF network, are other U.S. utilties considering using this same RF network for traditional distribution automation applications (i.e. wireless RF...