PBO (recloser) is the power breaker (PMT) equipped with control devices and reclosing relay Reclosing relay is relays that can detect the flow disturbances and ordered PMT open (trip) and shut down again.
The fuction of reclosing relay / PBO PBO hook up to medium voltage air channels mounted on a frequent disorder phase short circuit to ground which is temporary in nature, serves to: • Normalize back medium voltage air channels or minimize disruption caused by temporary outages remain. • Security section in order to limit medium voltage air channels / localize the affected area.
Type of Reclosing relay Based on the type of reclosing command to the PMT can be classified into two types of reclosing relays, namely: • Single-shot Reclosing Relay :Relay can only give orders to the PMT reclosing time and the new one can perform reclosing after blocking the last time, If there is interference with the blocking period of time, PMT trip and can not reclose again (lock - out).
picture 1: PBO relay with a time Reclose
• Multi Shot Reclosing Relay.
o This relay can give orders to the PMT reclosing more than once. Dead time between reclosing can be set the same or different .
o If an interruption occurs, the relay OCR / GFR trip gave orders to the PMT at the same time also mengarjakan (mengenergize) Reclosing relay. o After the dead time t 1 is very short (less than 0.6 seconds), reclose relay orders to the PMT.
o If the interference persists, the PMT will return trip and reclosing relays will perform the second reclose after the dead time t 2 which is quite long (between 15-60 seconds).
o If the interference persists, then the PMT would return trip and reclosing relays will perform the third reclose after the dead time t 3.
o If the interference is still present in the blocking period tB 3, the PMT will trip and lock out.
o The use of multi-shot reclosing should doisesuaikan with a duty cycle (duty cycle) of the PMT.
o This relay can give orders to the PMT reclosing more than once. Dead time between reclosing can be set the same or different .
o If an interruption occurs, the relay OCR / GFR trip gave orders to the PMT at the same time also mengarjakan (mengenergize) Reclosing relay. o After the dead time t 1 is very short (less than 0.6 seconds), reclose relay orders to the PMT.
o If the interference persists, the PMT will return trip and reclosing relays will perform the second reclose after the dead time t 2 which is quite long (between 15-60 seconds).
o If the interference persists, then the PMT would return trip and reclosing relays will perform the third reclose after the dead time t 3.
o If the interference is still present in the blocking period tB 3, the PMT will trip and lock out.
o The use of multi-shot reclosing should doisesuaikan with a duty cycle (duty cycle) of the PMT.
picture 2: Diagram of Multi-Shot Reclosing work time Relay
Characteristic Reclosing Relay
• Fast tripping : to anticipate a temporary interruption.
• Delayed tripping : to coordinate with downstream safety.
• When the disturbance was quickly lost in the PBO operation will reset back to its initial state. If an interruption occurs after the reset, PBO start counting from the beginning.
• Repetitive: research recloser automatically after success.
• Non-repetitive: it requires manual reset (in case of permanent impairment and if the disturbance had been released).
• PBO or overcurrent relays Recloser is so characteristic of PBO and OCR is the same (see the characteristics of the OCR).
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