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Terminal ConnectionsDistribution arrester line terminals utilize a stainless steel
four cornered “Star Clamp” for maximum conductor rangeand speed of installation. The ground terminals utilize astainless steel “U clamp”. Both connectors securely clampaluminum or copper conductors from No. 10 solid through2/0 stranded. Joslyn specifies that no more than 20 foot-pounds of torque be applied to the line and groundterminals.
Transformer ProtectionThe level of protection an arrester can provide will decreasewhen utilizing long connecting leads (line and ground side).This is due to the inductive voltage drop which is added to
the discharge voltage of the arrester. Mounting an arresterdirectly to the transformer will yield excellent protectivemargins from a combination of controlled lead length andlow discharge voltages.
Available OptionsFor options, see Catalog Selection Guides (page AR-19 thru
22) and Accessories (page AR-26 and 27).
Fault-Current Withstand TestsFault-current testing, also known as short circuit testing,demonstrates an arrester failure based on the most probablefailure modes over a range of fault currents. Two failuremodes are tested: 1) a fuse wire runs along the side of theinternal valve elements to simulate and internal flashover(moisture or collar failure), 2) overvoltage the arrester untilthe resistive elements fail to simulate a system overvoltageexceeding the unit’s TOV capability.
ANSI/IEEE C62.11 1999, specifies the test procedures andacceptance criteria for fault-current tests on distributionsurge arresters. Joslyn’s arresters passed the fuse wire andovervoltage fault-current testing at the current levels anddurations listed in the applicable Fault-Current Data Tables.Conformance was shown by oscillograph recordings of current magnitude and duration conducted through thearresters. All units passed the acceptance criteria.
Initial venting and arcing. Continued arcing. Following the severe fault, the arrester remainedintact.
Zforce™ ‘ZNP’, ‘ZHP’ and ‘ZRP’ ArrestersPatent No. 5,923,518
‘ZNP’ (5kA Normal Duty Polymer, Rated 9, 10 & 18kV)‘ZHP’ (10kA Heavy Duty Polymer, Rated 3kV-36kV)‘ZRP’ (10kA Riser Pole Polymer, Rated 3kV-36kV)
Fault Current Withstand TestsFault current testing, also known as short circuit testing,demonstrates an arrester failure based on the most probablefailure modes over a range of fault currents. Two failure modesare tested:
• A fuse wire runs along the side of the internal and valveelements to simulate an internal flashover (moisture orcollar failure).
• Overvoltage the arrester until the resistive elements fail tosimulate a system overvoltage exceeding the units TOV
capability.
ANSI/IEEE C62.11-1999, specifies the test procedures andacceptance criteria for fault current tests on distributionsurge arresters. Joslyn’s Zforce™ arresters passed the fusewire and overvoltage fault-current testing at the currentlevels and durations listed in the applicable Fault-CurrentData Tables. Conformance was shown by oscillographrecordings of current magnitude and duration conductedthrough the arresters. All units passed the acceptancecriteria.
kV Inch mm Inch mm Inch mm Inch mm Inch mm Inch mm Lbs. kg Std. Pk3 7.96 202 5.47 139 6.52 166 4.30 109 5.40 137 3.93 100 2.3 1.05 56 11.94 303 6.02 153 7.66 195 4.30 109 6.54 166 3.93 100 3.0 1.37 59 15.92 404 7.76 197 8.80 224 4.30 109 7.68 195 3.93 100 3.6 1.64 5
kV Inch mm Inch mm Inch mm Inch mm Inch mm Inch mm Lbs. kg Std. Pk3 7.96 202 5.47 139 6.52 166 4.30 109 5.40 137 3.93 100 2.3 1.05 56 11.94 303 6.02 153 7.66 195 4.30 109 6.54 166 3.93 100 3.0 1.37 5
The type “ZE” arrester incorporates surge protection in aone-piece, shielded elbow housing. It permits arresterinstallation on standard separable connector bushings,maintaining the dead front concept.
Performance
The type “ZE” arrester was developed specifically forprotection of underground distribution systems. It isinstalled at the open point of the underground system toprevent voltage wave doubling. When also installed at anintermediate point, voltage reflections from the open pointarrester are harmlessly discharged. The housing, made of peroxide cured EPDM rubber, is totally shielded with amolded conductive EPDM jacket to maintain the dead frontconcept. The one-piece construction requires no fieldassembly. The “ZE” dead front elbow arrester is approved byREA.
Durability
The “ZE” elbow arrester consistently withstands the
following minimum design tests:
• High Current-Short Duration: 2 current surges of 40kAmagnitude.
• Low Current-Long Duration: 20 current surges of 75amperes magnitude and 2000 microsecond duration.
• Duty Cycle: 22 discharges with a current surge of 5kAmagnitude and 8/20 microsecond wave shape.
• Following each of these tests, the “ZE” arrester remainsthermally stable and the discharge voltage increase atrated current is less than 10%.
Reliability
Rigid control standards insure that all material conforms toexacting engineering specifications. Each finished arrester issubjected to electrical tests to determine reference voltage,total leakage current and corona levels.
Application
The type “ZE” arrester rated voltage designates the 60Hzvoltage applied across the arrester terminals during the dutycycle test. In addition, the type “ZE” arrester MaximumContinuous Operating Voltage (MCOV) designates themaximum power frequency voltage that may be continuouslyapplied across the arrester in service. Selection of theappropriate type “ZE” rating is made on the basis that themaximum continuous line-to-ground voltage on the systemdoes not exceed the MCOV of the arrester.
The 10kV, 18kV and 27kV rated arresters are designed forapplication on nominal 15kV, 25kV and 35kV UD systems,respectively. The three ratings include standard ANSI/IEEE386 separable connector interface designs that arecompatible with major interface suppliers at each voltagelevel. Consult Joslyn for your specific requirements.
Permanent Markings
For permanent identification, the “ZE” arrester has moldedinto the housing “JOSLYN ZE ELBOW ARRESTER”. Stampedinto the stainless steel cover are “JOSLYN ZE ARRESTER”,arrester rated voltage, and date of manufacture. In additionto the above, a label contains all other information includingcatalog number and both rated voltage and MCOV rating.
* Compatible with standard ANSI/IEEE 386 interface designs1 Small 35kV Interface, 21.1/36kV Figure 7 of ANSI/IEEE 386, 1995.2 Large 35kV Interface, 21.1/36.6kV Figure 8 of ANSI/IEEE 386, 1995.
ProbesStandard load break probes are shipped assembled with each unit.