CEE Relays Ltd

Tel:   +44 1753 576477    Fax: +44 1753 825661
NP800 Series of relays
NP800 relay
A series of high-quality, reliable protection relays, the NP800 Series is designed to cover multiple protection functions in one package. Available as a retro-fit, variants of these relays can be produced to fit the same modular plug-in bases ("R-case" design) as many older CEE products.
NP800 products can be specified with single or twin RS-485 ports or an Ethernet port for MODBUS communication. 
These relays may be programmed using the Smartsoft software.
Click on the links below to download the individual brochures (in PDF format), or the link at the bottom to download the Application Guide for the whole series.
Common characteristics for the NP800 range: 
  • Auxiliary supply ranges: 19V to 70V or 85V to 255V (AC or DC). 
  • 2 setting groups. 
  • Self-diagnosis: RAM, ROM, EEPROM, output relays, A/D converters, auxiliary supply, monitoring of software execution time. 
  • Setting, reading, measuring and recording are all available locally or remotely. 
  • Complies with IEC 60255-4 standard. 
  • Monitoring of circuit breaker failure. 
  • Event recording: 250 events, 10ms resolution. 
  • 4 disturbance recordings.
  • Optional I/O extension board (included when directional function is present).*
*Not available with the NP800-R variants which have the "R-case" modular design
Relays for Railway applications
Power swing detection for AC railway networks
PDF, 1.8Mb
Fault locator for AC catenaries (conventional networks or those with autotransformers)
PDF, 1.9Mb
Multi-function protection for AC catenaries including distance protection
PDF, 2.1Mb
Relays for other Railway applications including fault locators for DC catenaries and traction group transformer protection are available in the Railway Relays page.
Network protection relays
Multi-function generator protection
PDF, 2.5Mb
Three-phase overcurrent and earth fault protection. Brochure also includes details of the NPIR800 which features an automatic recloser with one fast and three slow cycles. 
PDF, 1.9Mb
Three-phase overcurrent and earth fault protection (directional). Brochure also includes details of the NPIDR800 which features an automatic recloser with one fast and three slow cycles. 
PDF, 2.5Mb
Earth fault relay
PDF, 2.3Mb
Earth fault relay (directional)
PDF, 2.3Mb
Special sensitive directional or non-directional earth fault relay for un-earthed systems
PDF, 3.2Mb
Multi-function motor protection
PDF, 2.3Mb
Check synchronisation between up to four generators and an electrical network
PDF, 2.7Mb
Automatic synchronisation between generators and an electrical network
PDF, 2.3Mb
Check synchronisation between two power supplies or both sides of a bus-tie on a network
PDF, 2.7Mb
Three-phase over- / under- voltage and over- / under- frequency protection
PDF, 2.0Mb
Zero-sequence overvoltage relay
PDF, 2.5Mb
Multi-function power relay including real- and reactive- power and phase angle protection
PDF, 2.0Mb
Temperature monitoring relays
Temperature monitoring relays for connection to Pt100 probes with 4 (STEP840R) or 6 (STEP860R) channels.  Unlike other NP800 relays, these devices are only available in the "R-Case" housing. 
PDF, 1.5Mb
Having trouble selecting a relay?  Download the
PDF, 2.5Mb
For a general overview of NP800 relays, download the 
PDF, 3.2Mb