Specifications

32
RF SOLUTION-CITEL
●
VG technology by CITEL
In order to improve the surge protection efficiency, CITEL
has developed a patented technology which combines high
energy varistor (MOV) network and specific gas tube (GDT) :
by this way, the
<< VG >> Type 1 surge protectors (DS150VG,
DS250VG, DUT250VG) can get higher performances in :
- Protection level,
- Life duration (due to the suppression of leakage current),
- Continuous operation and power quality (no follow current)
- End of life behaviour.
For instance, these features allow to reach, with a single
stage of surge protection, the same protection efficiency as a
double stage association (Type 1 + Type 2 SPDs).
Surge protectors parameters
Surge protectors are defined by a series of electrical
specifications which will help the user to select the right
protection specific to its installation :
●
Operating voltage - Uc
The maximum continuous operating voltage (MCOV) Uc is the
maximum r.m.s voltage which may be applied continuously to the
SPD.
●
Temporary overvoltage - U
T
The temporary overvoltage U T (TOV) is the maximum r.m.s.
value the surge protector can withstand during 5 seconds,
without failure. In many cases, this parameter U
T is equal to Uc.
●
Discharge current - In and Imax
The maximum discharge current (Imax), applicable to Type 2
SPD, is the maximum impulse current 8/20
㎲
a surge
protector can withstand without destruction .
The nominal discharge current (In) is the level of impulse
current a surge protector Type 1 or Type 2 can withstand
repeatedly (15 surges) without destruction.
●
Impulse current - Iimp
The impulse current (Iimp), used in Class I test applicable to
Type 1 SPDs, is the maximum impulse 10/350
㎲
current a
surge protector can withstand without destruction. This test
simulates the effect, on AC power surge protectors, of a
direct lightning strike on an installation.
●
Open circuit voltage - Uoc
This parameter is used only for Class III test, applicable to
Type 3 SPD and consists of the injection of a combination
wave (1.2/50
㎲
in open circuit - 8/20
㎲
in short circuit).
●
Protection level - Up
This is the maximum voltage on the surge protector output
when subjected to an impulse current equivalent to its
nominal discharge current(In). Therefore this parameter
characterizes the performance of the SPD in limiting the
transient overvoltage across its terminal in order to protect
the equipment.
●
Residual voltage - Ures
This parameter is the residual voltage across the SPD
terminal during the injection of a selected impulse current. It
may be lower than the protection level Up, for surge
protectors like
<< VG >> series.
Type of surge protectors
The AC power surge protectors are split into 3 categories by
IEC 61643-11 and EN 61643-11 standards, with the
following 3 classes of test. These different tests depend on
the location of the surge protector in the AC network and on
the external conditions.
●
Type 1 Surge Protectors
Type 1 surge protectors are designed to be installed where a
direct lightning strike risk is high, especially when the
building is equipped with external lightning protection system
(LPS or lightning rod). In this situation, EN 61643-11 and IEC
61643-11 standards require the Class I test to be applied to
surge protectors : this test is characterized by the injection of
10/350
㎲
impulse current in order to simulate the direct
lightning strike consequence. Therefore these Type 1 surge
protectors must be especially powerful to conduct this high
energy impulse current.