Surge protection devices for electrical equipment of 6 and 10 kV type UZPE are designed to protect AC electrical equipment operating at 50 Hz, with voltage classes of 6 and 10 kV, in networks with isolated neutral, from switching and lightning overvoltages. They serve as replacements for valve arresters and traditional surge arresters.

Construction and operating principle:

The device consists of a surge arrester in a hermetically sealed polymer housing, reinforced with metal flanges, mounted on an insulating bracket. A disconnector is included in the grounding circuit of the arrester, which automatically breaks the grounding circuit in case of arrester failure, eliminating a persistent ground fault. The damaged arrester is easily detected visually. Phase-to-ground insulation is provided by an insulating bracket based on a 10 kV line post insulator, suitable for operation in areas up to pollution degree 4. The protective housings of the arrester and bracket are made of silicone-organic composition with high hydrophobicity, tracking and erosion resistance, and flammability class FV0.

Main technical characteristics:

• Network voltage class: 6 kV or 10 kV.
• Maximum continuous operating voltage of the arrester (Uндр): 7.6 kV for 6 kV; 12.7 kV for 10 kV.
• Nominal discharge current: 5 kA or 10 kA.
• Residual voltage at lightning current impulses 8/20 µs with amplitude 5000 A: 25.2 kV for 6 kV; 42.1 kV for 10 kV.
• Residual voltage at switching current impulses 30/60 µs with amplitude 500 A: 19.7 kV for 6 kV; 32.8 kV for 10 kV.
• Number of withstandable current impulse impacts: 20 for lightning current impulses 8/20 µs with maximum value 5000 A.
• Creepage distance of the arrester: 190 mm for 6 kV; 265 mm for 10 kV.
• Pollution degree: 3 for 6 kV; 2 for 10 kV.