Line protection device

♦Three stage over current protection (optional lockout over current)

♦Two stage zero sequence current protection

♦Overload protection

♦ Reclose protection

♦ Closing acceleration protection

♦ Inverse-time protection

♦ Charge protection.

♦ Low voltage protection

♦ Overvoltage protection

♦ Low frequency protection

♦ PT breaking protection

♦ I、U、P、Q、cosφ、Hz、8 road switch quantity gathering

 
1 Protection function 

1）Three stage over current protection

Each stage is respectively provided protection function of cast back and each section protection the a operating current and operating time of fixed value, Each stage of protection is independent of each other.

Each can choose the lockout overcurrent protection.

The action condition:

When choicepure overcurrent

a）I> Overcurrent protectioncurrent setting value 

b）T> Overcurrent protection time setting value

c）Overcurrent i protection control word- simple over curren

When choicelockout overcurrent 

a）I> Overcurrent protectioncurrent setting value 

b）T> Overcurrent protection time setting value

c）U< Voltage lockout overcurrent setting value

d）Overcurrent i protection control word- lockout overcurrent

2）Two stage zero sequence protection

Each stage is provided with a Control word to protect the function of the investment, when the zero sequence current is greater than the set current, the time delay trip or alarm, Each stage of protection is independent of each other.

The action condition:

a）Io>Zero sequence overcurrent protection current setting value 

b）T>Zero sequence overcurrent protection time setting value

c）Zero sequence overcurrent protection control word:1-Trip  2-Alarm

3）Overload protection

When any phase current is greater than the set current, the time delay trip or alarm. 

The action condition:

a）I > Overload protectioncurrent setting value

b）T>Overload protectiontime setting value

c）CB is in closed position 

d）Overload protectioncontrol word: 1-Trip  2-Alarm 

4）Reclose protection

When reclosing function input, a switch in a 15s after and meet the charging conditions , reclosing charging is complete (The recloser ready, can make reclosing). 

Once the protection tripping or switch tripping, the reclosing time delay after reclosing startup. 

The action condition:

a）I > Reclose protectioncurrent setting value

b）T>Reclose protectiontime setting value

c）CB is in closed position 

d）Reclose protectioncontrol word: 1-ON 

5）Closing acceleration protection 

When manual closing, remote control closing and reclosing, if closing on a fault line, when any one phase current is larger than the current setting, the device after short time delay trip. A device to monitor the closing position in a closing time, accelerate the exit automatically after 3 seconds. 

The action condition:

a）I > Closing acceleration protection setting value

b）T> Closing acceleration protectiontime setting value

c）CB is into closed position 

d）Closing acceleration protectioncontrol word: Pure overcurrent/ lockout overcurrent

6）Charge protection 

Applied to bus protection. When the bus is closed , device monitor closing position, in jump 3S, in any one phase current is greater than the set value, device after the trip delay. 

7）I nverse time overcurrent protection

The protection function by controlling the word choice cast back, setting a threshold value and inverse time current inverse time constant.

The inverse time characteristic equation is as follows: 

: Inverse time current threshold value; : Overcurrent time coefficient value 

The action condition:

a）I>I nverse time overcurrent protectioncurrent setting value

b）T>Inverse time overcurrent protectiontime setting value

c）Inverse time overcurrent protectioncontrol word:1-ON

8）Overvoltage protection

When the voltage is greater than the set value and CB is in closed position,, the time delay trip or alarm. 

The action criterion: 

a）Max(UAB、UBC、UCA)>Overvoltage protection voltage setting value

b）T>Overvoltage protection time setting value

c）CB is in closed position 

d）Overvoltage protection control word: 1-Trip  2-Alarm 

9）Low voltage protection

When the voltage is less than the set value and CB is in closed position, the time delay trip or alarm.

The action condition:

a）Max(UAB、UBC、UCA)< Low voltage protectionvoltage setting value

b）T>Low voltage protectiontime setting value

c）CB is in closed position 

d）Low voltage protectioncontrol word: 1-Trip  2-Alarm 

10）Low frequency protection 

When the system frequency is less than the set value, the time delay trip or alarm.

The action condition:

a）I > Low frequency protection current setting value

b）f< Low frequency protectionfrequencysetting value

c）T< Low frequency protectiontime setting value

d）Low frequency protectioncontrol word: 1-Trip  2-Alarm

11）PT breaking protection

Any difference between the two phase voltage >18V; Umin<0.1Un. I have a current (>0.8In); meet the above criteria, sentenced to TV break, delay 10s alarm, report "TV breaking alarm". 

12）Control loop break 

CB control loop is normal, the TWJ and HWJ are in a state of 1 and the other one is 0. the two are 1 or 0, It shows that the control loop or the DI loop is abnormal, the 10s delay times "control loop break".