Several technologies exist on the market for surge protection or power network:
- Metal Oxide Varistor (MOV)
- Air Gap + Trigger
- MOV + Gas-filled Spark Gap (GSG) (CITEL's VG Technology)
VG technology is CITEL's exclusive and patented technology based on the use of specific types of Gas-filled spark gaps (GSG) in conjuntions with Metal oxide varistors (MOV). These components, the result of over 75 years of experience in the gas discharge tube field, have a behavior adapted to the power network and provide robustness and working stability: their association with varistors combines the advantages of both technologie.
CITEL originally developed the “VG” technology for low voltage Type 1 surge protectors and has then extended it to Type 2 surge protectors and to Photovoltaic applications.
Advantages of VG Technology
1. GAS-FILLED-SPARK GAP (GSG)
CITEL VG surge protectors are using specific gas discharge tubes: GSG. These essential components are the result of over 80 years of experience in the gas discharge tube field, are meant for power network and ensure a perfect electrical stability.
→ Increase reliability
2. VERY LOW CLAMPING LEVEL AND HIGH SURGE CURRENT CAPABILITY
GSG are able to conduct very high surge currents (Iimp, Imax) with a very low residual voltage (Up). Such characteristics could only previously be reached with the combination of a Type 1 and a Type 2 surge protector.
→ Equivalent to Type « 1+2+3 » or « 2+3 » solutions
→ Maximum efficiency
→ Compact design
3. INCREASED TOV WITHSTAND
VG surge protectors can handle very high TOV levels (Temporary Over Voltage) up to 450Vac without any failure or degradation to the level of protection.
→ Increased reliability for areas with unstable power networks
4. NO FOLLOW CURRENT
Unlike to “Air Gap” technologies, “VG” Technology does not create any follow on current. VG ->Increased service continuity by no tripping of the upstream overcurrent protection device (OCP) during surge events.
→ Improvement of the network quality (no power line disturbances)
→ Easy selection
5. ROBUSTNESS AND RELIABILITY
All the components of the VG surge protector are designed to handle high impulse discharge currents without any assistance from auxiliary systems. On the contrary, the “Triggered Air Gap” technology includes a control circuit, using very sensitive components, which could be stressed by a part of the surge current and will eventually fail.
→ Increase reliability
→ Better life expectancy
6. SAFE DISCONNECTION AND DEVICE STATUS SIGNALIZATION
VG surge protectors use a safe disconnection system and provide real-time status indication of internal components. For a “Triggered Air Gap” technology, the disconnection and signalization only can provide the status of the control circuit and not the main protection circuit.
→ Safe and efficient maintenance
7. No AGEING
During normal operation, in addition to transient events, varistors are always conducting a small amount of current. This leakage current can be stressful to the varistor over time, especially in DC power systems, and cause the varistor to age prematurely → Maximum life expectancy
8. EASIER SURGE PROTECTION COORDINATION
In the case of coordinated SPD installations, the surge protector downstream a VG surge protector does not need any special consideration, such as a sufficient distance between locations, in order to ensure a working coordination between multiple SPDs. Note: due to its optimized protection level, the VG surge protector can be used without any additional surge protector
→ Easier to use