NSD570 - fast, reliable and secure transmission of protection signalsA secure and uninterrupted supply of electricity is only possible with the help of comprehensive protection and control functions, which ensure the reliable operation of the power system.As the complexity and ratings of electrical power systems increase, so do also the demands on the protective devices and systems, which have to protect them from damage and preserve power system stability.
Protection equipment in conjunction with communication linksprovide the best possible means of selectively isolating faults on high voltage transmission lines, transformers, reactors and other important items of electrical plants.To prevent the power system from failure and damage, the teleprotection system enables to selectively disconnect the faulty part by transferring command signals within the shortest possible time.
The NSD570 is suitable for all types of protection commandtransmission in “State Comparison” protection schemes:− Transfomer, reactor, generator and line protection− Single-circuit and double-circuit lines− Including the protection of teed feeders with single or multiple tee-offsi
Depending on the protection scheme in use, the command signals trip the remote circuit-breaker either directly (direct tripping) or are first enabled by the local protection device (permissive tripping).
Other protection schemes involve tripping prevention by the local protection device (blocking).
A fundamental requirement in all these applications is that command signals are communicated reliably at the highest possible speed. In the event of a fault on the protected unit, the command signals must be received at the remote end in the shortest possible time even if the channel is disturbed by the fault (dependability).
On the other hand, interference on the communications channel must never cause unwanted operation of the protection by simulating a tripping signal when there is no fault on the power system (security).
The most important performance features of a teleprotectionequipment are therefore transmission time, dependability andsecurity. From the communications engineering point of view, the bandwidth or data rate a teleprotection equipment occupies must also be taken into account.i
