Transformer Pressure Relief Device

DIN & IEC Standard Transformer Pressure Relief Device (PRD) is an essential safety protective component mounted on the top or side wall of oil-immersed distribution & power transformers and on-load tap changers, functioning as the core anti-explosion safeguard for transformer tank.

When internal short-circuit, winding breakdown or abnormal overheating occurs inside the transformer, insulating oil vaporizes rapidly and generates massive instantaneous gas, causing sharp tank pressure surge. Once internal pressure exceeds factory preset cracking value (standard 30kPa~70kPa per DIN/IEC requirement), the PRD instantly opens within 3~10ms to discharge excess gas and partial transformer oil, effectively avoiding tank bulging, rupture or explosion caused by overpressure; after pressure drops to reset threshold, the valve automatically recloses tightly to block moisture, dust and outside air entering the tank and prevent oil leakage in normal operation.

Our PRD strictly follows DIN industrial specification & IEC60076-22-1 standard, main housing adopts high-strength cast aluminum/ductile iron with anti-rust powder coating; internal spring is precision alloy steel with stable elastic performance after fatigue test; sealing ring uses high-temperature resistant Viton/FKM rubber, compatible with all types of mineral transformer oil and anti-aging under long-term oil immersion. Two mainstream installation structures available: threaded connection (G1", M38/M48 DIN thread) and flange connection (DN25/DN35/DN50/DN80), fully interchangeable with European MESSKO, CEDASPE original DIN-type PRD for OEM assembly and after-market replacement.

Optional Configuration

Electric alarm micro-switch: NO+NC double contacts, outputs remote alarm signal when valve actuates, connects to transformer control cabinet for real-time monitoring；

Visual pop-up indicator: protruding red marker after pressure release for on-site visible fault reminder；

Oil deflector hood: directional drainage cap to avoid splashing hot oil randomly during pressure exhaust；

Protection grade optional up to IP65/IP67 for coastal, high-humidity and heavy salt-fog working conditions.

Core Advantages

DIN calibrated opening pressure, precise tolerance ±5kPa, stable action without mis-opening under normal thermal expansion pressure of transformer oil；

Ultra-fast opening response below 10ms, excellent transient overpressure relief performance for sudden short-circuit fault；

Corrosion-resistant whole structure, long service life, maintenance-free during transformer normal service cycle；

Multiple mounting directions: vertical, inclined or horizontal installation without changing preset opening pressure；

Customizable cracking pressure, connection size and switch combination per customer’s transformer drawing.

Main Technical Parameters

Executive Standard: DIN, IEC60076, EN50216-1, JB/T7065

Rated Opening Pressure: 30kPa/50kPa/70kPa (custom 30~150kPa available)

Connection Spec: Thread G1"/M38/M48; Flange DN25/DN35/DN50/DN80

Material: Cast aluminum body + stainless steel spring + Viton sealing gasket

Application: 10kV/20kV/35kV oil immersed distribution transformer, on-load tap changer, current transformer