| Overview |
SEL electric field reset fault indicators (type E-ERL) derive their operating power from the potential gradient around high-voltage power lines. The E-ERL’s inrush restraint option blocks targeting for recloser operations. When the upstream protection operates, the indicator senses the collapse of the voltage field and prohibits tripping until the utility is able to restore normal system conditions. The E-ERL’s versatility and
reliability have made it a favorite for utilities working to improve their reliability statistics.
|
| Applications |
Utilities and other users typically apply E-ERL fault indicators on overhead conductors on main line feeders: one set at the first upfeed and one set at each tap location. Locate the indicators so that it is easy to identify whether the fault location is on the tap or further down the feeder. Installing E-ERLs before each downfeed and after each upfeed allows the utility to determine whether the fault is in the underground section. Installing one of EOS Manufacturing’s many models of underground fault indicators can help to further narrow in on the location of the fault along the underground portion of line. Midfeeder disconnects provide another optimal location for E-ERLs. Once a lineman is dispatched to the midpoint, he opens the midpoint and uses the E-ERL to determine which half of the feeder contains the fault. Then, the utility can quickly restore half of the feeder while the lineman patrols the remaining half of the feeder.
E-ERL fault indicators with snap action clamps work well on livefront switchgear: simply clamp the E-ERL onto the barrel of the cable termination lug.
|
| Mounting Options |
Mount E-ERL fault indicators on bare or covered overhead lines using one of three different clamping styles. In addition to the Standard option, SEL offers two other clamping options, “Constant Calibration” and “Snap Action.” The Constant Calibration Clamp option maintains nominal trip rating accuracy (+/- 10%) throughout the clamping range. To use the E-ERL in switchgear applications, add the Snap Action Clamp option: it allows the E-ERL to fit easily on the barrel of the lug.
|
| Specifications |
| Power Source |
Electric field potential gradient |
| Nominal Trip Ratings |
50 to 1200 A |
| Trip Tolerance |
+/- 10% |
| System Voltage Range (L-L) |
86600 V to 69 kV |
| Reset Time |
Approx. 5 minutes at 5 kV L-N,
(higher voltages result in quicker reset) |
| Display |
Reflective red target |
| Maximum Fault Current |
25 kA for 10 cycles at 60 Hz |
| Trip Response Time |
1 ms |
| Inrush Restraint Response Time |
300 ms |
Outer Diameter
Clamping Range |
0.25” to 1.6” (please specify clamping diameter or range when ordering) |
| Housing Material |
UV-stabilized polycarbonate resin |
| Clamp Material |
Stainless-steel clamp with a UV-stabilized rubber sleeve |
| Temperature Range |
-40° to +85°C |
| Approximate Weight |
240 g (0.53 lbs) |
|
| Options |
- “DT” 24 ms Delayed Trip
- “CC” Constant Calibration
- “S” Snap Action Clamp
- Consult EOS for additional features
|
Fault Indicators