Brief Introduction
L-22GYW current transformer is suitable for power measuring,electronic measuring instrument and relay protection in 22KV,60HZ neutralpoint effective ground system.
Type and Meaning
Service condition
3.1 Installation site:outdoor
3.2 Sea leveled altitude:≤2500m
3.3 Surrounding temperature:MAX:+45oC
Daily mean: +30oC
MIN:-25oC
3.4 Atmosphere condition:have no serious pollution in atmosphere,the pollution grade islll.
3.5 Minimum creepage distance:≥1256mm
Basic parameter and main technical performance in
4.1.1 Highest voltage of equipment 25KV
4.1.2 Rated primary voltage 22KV
4.1.3 Rated primary current 500A
4.1.4 Rated secondary current 5A
4.1.5 Rated frequency 60HZ
4.1.6 Secondary winding combination 0.2/5P20/5P20
4.1.7 Rated output
Protection class 30VA
Measuring class 30VA
4.2.1 Current errors and phase errors
a.Measuring winding
When secondary load is one value of 25-100% reated load(cosΦ=0.8lag),current limit value and phase errors under rated frequency od not exceed the value in the table 1.
b.Protection winding
Under rated frequency and rated load,current errors,phase errors and composite errors do not exceed the value in the table 2.
4.2.2 Protection class accuracy limit factor:20
4.2.3 Measuring class instrument security factor:Fs≤5
4.2.4 Temperature rise limit value
Temperature rise if all the parts of the pruduct can not exceed 55K,when current transformer is at primary current and rated output.
4.2.5 Insulation level
4.2.5.1 Internal insulation
primary winding to secondary winding or to earch 95KV(valid) 1 min
between sects of primary winding 3KV(valid) 1 min
secondaty winding to secondary or to earth 3KV(valid) 1 min
4.2.5.2 External insulation
Dry test voltage 95KV(valid value)
Wet test voltage 95KV(valid value)
4.2.5.3 Rated impulse withstand voltage at sea level
Instrument transformer can carry 1.2/50μs impulse full-wave test voltage positive and negative polarity 15 times without breskdown or flashover.200KV(peak)
4.2.6 Rated short time thermal current 25KA(valid value) 1s
4.2.7 Rated dynamic current 80KA(peak)
4.2.8 Polarity Subtractive
Construction
5.1 Partial dicharge level
Applied 80% of power frequency withstand voltage continuously 1 min.then reduce voltage to 1.2UmKV,measuring partial discharge value does not exceed 5PC in 30s.
5.2 Dielectric loss factor
At 10 KV,power frequency 60±0.5HZ,temperature 15oC-25oC,dielectric loss factor of instrument transformer,tan δ≤0.5%.
5.3 Radio interfefence level
Wheh 1.1Um/KV,the radio interference does not exceed 350 μV.
5.4 Mechanical strength of primary terminals(P1.P2)
A:horizontal strength 1500N
B:vertical strength 500N
C:lateral strength 500N
5.5 Transformer oil
5.5.1 Type:No.25 transformer oil made in china
5.5.2 Breakdown voltage ≥45KV
5.5.3 Water content ≤20ppm
5.5.4 At 90oC and 2KV,dilectric loss factor does not exceed 0.004.
Service and maintenance
6.1 before the installation,inspect the sealed place and welding,it has no oil leakage.the oil surface is normal,if not,it should oiling the same type oil.
6.2 The isinstrument transformer should be fixed on the platform with foot bolts.
6.3 The oil drawing from the bottom,its electric intensity is not more than 50KV.
6.4 The product should veiled when it storage,before the operation,it should not sun or rain.the product shoud packed.
Notic when placing a order
a.type of instrument transformer
b.rated current ratio
c.rated frequency
d.accuracy class combination and rated output
e.sea leveled altitude
Table 1 | |||||||||||||||
Accuracy Class | Current error(±%)(At the following rated current percentage) | Phase error(at the following rated current percentage) | |||||||||||||
±(') | ±card | ||||||||||||||
1 | 5 | 20 | 100 | 120 | 1 | 5 | 20 | 100 | 120 | 1 | 5 | 20 | 100 | 0.9 | |
0.5s | 1.5 | 0.75 | 0.5 | 0.5 | 0.5 | 90 | 45 | 30 | 30 | 30 | 2.7 | 1.35 | 0.9 | 0.9 | 120 |
0.2s | 0.75 | 0.35 | 0.2 | 0.2 | 0.2 | 30 | 15 | 10 | 10 | 10 | 0.9 | 0.45 | 0.3 | 0.3 | 0.9 |
0.1 | - | 0.4 | 0.2 | 0.1 | 0.1 | - | 15 | 8 | 5 | 5 | - | 0.45 | 0.24 | 0.15 | 0.3 |
0.2 | - | 0.75 | 0.35 | 0.2 | 0.2 | - | 30 | 15 | 10 | 10 | - | 0.9 | 0.45 | 0.3 | 0.15 |
0.5 | - | 1.5 | 0.75 | 0.5 | 0.5 | - | 90 | 45 | 30 | 30 | - | 2.7 | 1.35 | 0.9 | 0.3 |
Table 2 | ||||
Accuracy | Current error(±%)(At reted primary current) | Phaes error(at rated primary current) | Comosite error(at rated accuracy limit current) | |
±(') | ±card | |||
5P | ±1 | ±60 | ±18 | 5 |
10P | ±3 | - | - | 10 |