File Ref: CT235009EN Effective April 2020 COOPER POWER New Issue SERIES UltraSIL™ Polymer-Housed VariSTAR™ Type U3AF Class SM Station-Class Surge Arresters certified test report CT235009EN Page: 2 of 19 UltraSIL™ Polymer-Housed VariSTAR™ Type U3AF Class SM Station-Class Surge Arresters CERTIFICATION Statements made and data shown are, to the best of our knowledge and belief, correct and within the usual limits of commercial testing practice. Timothy Smith Michael M. Ramarge Principal Engineer Manager of Product Engineering - Arresters CT235009EN Page: 3 of 19 INTRODUCTION This test report certifies that the UltraSIL™ Polymer-Housed VariSTAR™ Type U3AF Station-Class Surge Arresters were successfully tested to IEC60099-4™-2014 standard " Metal-oxide surge arresters without gaps for a.c. systems” TEST PROGRAM OBJECT To demonstrate that the UltraSIL Polymer-Housed VariSTAR Type U3AF Station-Class Surge Arresters meet all performance requirements. PROCEDURE The following design tests were performed on a sufficient number of samples to demonstrate all performance requirements are met. TYPE TESTS Test Description Per IEC60099-4 ™-2014 section A. Insulation Withstand test 10.8.2 B. Residual Voltage test 10.8.3 C. Test to verify long term stability under continuous 10.8.4 operating voltage D. Test to verify the repetitive charge transfer raring, Qrs 10.8.5 E. Heat dissipation behavior of test sample 10.8.6 F. Operating duty test 10.8.7 G. Power-frequency voltage versus time test 10.8.8 H. Short-circuit Test (Design A) 10.8.10 I. Test of the bending moment 10.8.11 J. Weather ageing test 10.8.17 RESULTS UltraSIL Polymer-Housed VariSTAR Type U3AF Station-Class Surge Arresters met all performance requirements. CT235009EN Page: 4 of 19 TEST A INSULATION WITHSTAND Report Number B8025339 and C0005947 Certifying Laboratory CESI OBJECTIVE The voltage withstand tests demonstrate the voltage withstand capability of the external insulation of the arrester housing. PROCEDURE Samples of the longest unit were tested to represent arresters < 245kV, the results are detailed in report B8023734. The internal parts of the arrester were removed to permit these tests. The housing of polymer-housed surge arrester was arranged for the tests with an insulating support as provided by the client. Four shorting wires connected the head of the insulating support to its base. The base of the insulating support was connected to the earth of the test laboratory. The outside surface of housing of polymer-housed surge arrester was cleaned. The test voltage was applied between the upper line terminal of the arrester housing and its end terminal connected to the insulating support and earth. Lightning impulse voltage test (dry) The housing of polymer-housed surge arrester was subjected to a standard lightning impulse voltage dry test according to IEC 60060-1 and IEEE Std 4. The applied voltage was the specified withstand voltage shown in Table 1 below. Fifteen consecutive impulses at the specified test voltage value were applied for each polarity. Power-frequency voltage test (dry and wet) The housing of surge arrester was subjected to a power-frequency withstand voltage test in dry and wet conditions. For wet conditions the characteristics of the rain were according to IEC 60060-1 and IEEE Std 4. The applied voltage was the specified withstand voltage shown in Table 1 below. Table 1 Withstand Voltage kV peak Ring Size (mm) None 660 1067 Lightning impulse withstand voltage (dry) 635 617 513 Switching impulse withstand voltage (wet) 527 534 428 Power-frequency withstand voltage (dry) 375 344 304 Power-frequency withstand voltage (wet) 288 317 240 CT235009EN Page: 5 of 19 Insulation withstand tests were carried out on a complete arresters assemblies and equipped with the complete external grading system. This represents arresters >245kV, the results are detailed in report C0005947 The internal parts of the arrester were removed to permit these tests. The test voltage was applied between the line terminal and the earthed base. The arrester for the tests has been placed on pedestal (Height=1800mm) Lightning impulse voltage test (dry) The housing of polymer housed metal-oxide surge arrester was subjected to a lightning impulse voltage test in dry conditions following the measurement practices in accordance with the specification as given in IEC 60060-1. Fifteen consecutive impulses of 910kVpeak were applied, for each polarity, between the arrester line and ground terminals. The applied voltage was determined by multiplying the specified withstand voltage by the correction factor taking into account air density and humidity at the moment of the test (as per IEC 60060-1). Switching impulse voltage test (wet) The housing of polymer housed metal-oxide surge arrester was subjected to a switching impulse voltage test in wet conditions following the measurement practices in accordance with the specification as given in IEC 60060-1. Fifteen consecutive impulses of 872 kVpeak were applied, for each polarity, between the arrester line and ground terminals. The applied voltage was determined by multiplying the specified withstand voltage by the correction factor taking into account air density at the moment of the test (as per IEC 60060-1). The characteristics and the parameters of the artificial rain were according to the procedure given in IEC 60060-1. RESULTS No disruptive discharges occurred for any test Therefore the housing of the surge arrester passed the lightning impulse, switching impulse and power frequency voltage tests The insulation withstand value for VariSTAR Type U3AF are shown in Table 2 . CT235009EN Page: 6 of 19 TEST B RESIDUAL VOLTAGE TEST Report Number B9011514 Certifying Laboratory CESI OBJECTIVE To determine the maximum residual voltage characteristics of the arresters with various waveforms. PROCEDURE Sample arresters were impulsed using the following wave shapes; Lightning impulse residual voltage test wave-shape 8/20 μs peak current 40 kA Switching impulse residual voltage test wave-shape front time in the range 30μs to 100μs, tail time twice the virtual time peak current 2000 A (according to table 1 of the reference standard) Steep current impulse residual voltage test wave-shape front time equal to 1 μs, tail time less than 20 μs peak current In = 10 kA (according to the reference standard) The residual voltage crest was measured. RESULTS Table 3 shows the maximum residual voltages for the VariSTAR Type U3AF Station-Class Surge Arresters. CT235009EN Page: 7 of 19 TEST C TEST TO VERIFY LONG TERM STABILITY UNDER CONTINUOUS OPERATING VOLTAGE Report Number B9012279 Certifying Laboratory CESI OBJECTIVE Demonstrate that the power loss factor remains stable during ageing . PROCEDURE Measure the Power Loss factors Pstart,, Pmin and Pend from VariSTAR samples of the 76 mm nominal diameter that were energized at the specified power-frequency voltage for a total duration of 1000 hours while maintained at the temperature of 115 °C. During the ageing period the following criteria have to be met: -any increase of power losses from Pmin was not greater than 1,3 times Pmin for each MO resistor -all measurements of power losses including the final measurement was not greater then 1,1 times Pstart RESULTS The acceptance criteria were fulfilled and therefore the test result is positive CT235009EN Page: 8 of 19 TEST D TEST TO VERIFY THE REPETITIVE CHARGE TRANSFER RATING Qrs Report Number B9011518 Certifying Laboratory CESI OBJECTIVE The purpose of this test is to verify the repetitive charge transfer rating, Qrs, of an arrester. Repetitive charge transfer capability is specified as an impulse current stress that can be withstood by the MO resistors of an arrester twenty times without mechanical or unacceptable electrical damage. PROCEDURE Ten VariSTAR samples of the 51 mm nominal diameter with the greatest nominal length used in the arrester design with the highest residual voltage at the classifying current that is used in the design. Measurement of the lightning impulse residual voltage at the nominal discharge current and the power frequency reference voltage at the reference current. Calculation of the corrected values of Qrs associated to each test sample according to clause 7.3.1 of the reference standard. Application of twenty long-duration current impulses with approximately rectangular waveshape (virtual total duration from 2ms to 4 ms) delivered in ten groups of two operations each. The interval between consecutive impulses of the same group has been about 60 seconds. Between different groups the samples have been let to cool down to near ambient temperature. Measurement of the power frequency reference voltage at the reference current and the lightning impulse residual voltage at the nominal discharge current for comparison with initial value. Application of a current impulse 8/20 μs of an amplitude resulting in a current density of 0,5 kA/cm2 Visual inspection RESULTS VariSTAR Type U3AF Station-Class Surge Arresters met the charger transfer rating of 1.6 C as claimed with ten samples passing the requirements of 20 impulses, <5% change in residual voltage and reference voltage, and no physical damage. CT235009EN Page: 9 of 19 TEST E HEAT DISSIPATION BEHAVIOR OF TEST SAMPLE Report Number B9011517 Certifying Laboratory CESI OBJECTIVE For tests involving thermal recovery in which prorated arrester sections are used, it is required that the sections are thermally equivalent to the complete arrester. If, at any time, the measured cooling curve of the section falls below the measured cooling curve of the complete arrester, compensation must be made by adding a factor, k, to the relative overtemperature, Trel, such that the cooling curve of the section is at or above the cooling curve of the complete arrester over the entire cooling period PROCEDURE The following procedure was followed to demonstrate this equivalency. The first test on the complete arrester followed by a test on the prorated section. Test procedure on complete arrester The complete arrester was placed in the testing laboratory at still air ambient temperature of 29,8 °C.