Trihal cast resin dry type transformers (ENG) - Trinet

TrihaltestsTrihal resists to loadvariations and overloads.Trihal is classified C2 and E2as per the HD 464 S1* standard.figure 1: C2afigure 2: C2bfigure 3: E2aclimatic tests test C2a(as per the HD 464S1* standardappendix ZB.3.2.a)Thermal shockKema laboratory in HollandTest report No 31813.00-HSL 94-1258630 kVA No 601896.01 test methodThe Trihal transformer was placed for 12 hours ina climatic room where the ambient temperaturewas initially lowered down to –25°C (±3°C) in8 hours (figure 1). evaluation of resultsThe Trihal transformer was subjected to a visualinspection followed by dielectric tests (appliedvoltage and induced voltage tests at 75% ofstandard values) and partial dischargesmeasurements.Partial discharges level is critical for cast resintransformer reliability.The standard HD 538.1-S1 imposes lower than orequal to 20 pC. The result for Trihal transformerwas 2 pC (1) .No flashover or breakdown occured during thedielectric tests. test C2b in addition**(as per the HD 464S1* standard appendixZB.2.2.b)Thermal shockKEMA laboratory in HollandTest report No 31882.00-HSL 94-1259 test methodThe coils of the Trihal transformer were alternatelyimmersed in 2 tanks, one containing boilingwater >96°C, the other containing iced water