SDB – Smart Device Expert Bushing, CT and PT Monitor

Condenser bushings are subject to stress due to transient over voltages like surges and atmospheric discharges. Combined with the fact that they are impossible to test when the equipment is energised, they are one of the main areas of failure in transformers and reactors. Heavy fines are imposed when the equipment is unavailable during off-line tests. Off-line tests are ineffective because they are done periodically, yearly intervals, which cannot identify faulty equipment.

Treetech’s SDB Smart Device offers a solution in this situation because it permits online insulation diagnosis and continuous monitoring of leakage current changes, capacitance, and tangent delta for bushings, CT’s, VT’s and other equipment.  If problems are detected early, significant failures can be avoided and maintenance reduced or eliminated.

The experience gained from monitoring hundreds of bushings for several years in many countries led to the innovation of exclusive characteristics for the monitor, which arepatent  pending in Brazil and abroad:

• Indications for leakage  current, capacitance,  tangent  delta, capacitance and tangent  delta evolution trends, with predictions of time when alarm values will be reached;
• Colour display for intuitive bushing status  view and historical graphs. Options for touch-screen  or joystick interface;
• Embedded web pages for remote view of online measurements  and consultation of historical graphs,  as well as password controlled setting of equipment parameters;
• History of measurements and alarms in embedded SQL database,  facilitating storage and safe and efficient access to data,  plus complete integration  with remote online monitoring systems;
• Non-volatile Gigabyte mass memory expandable to 32 Gigabytes. Low maintenance internal clock without batteries;
• USB port for connecting laptop or memory stick for downloading data;
• Two optical fibre or RJ45Ethernet  ports with F.O. serial option; Wireless communication  through Wi-fi or GPRS modem;
• One RS485 port and a programmable RS232/RS485. Clock synchronism through IRIG-B;
• Open protocols: Serial IEC61850, DNP3.0 and Modbus RTU or through TCP/IP, FTP for remote   access  to files and databases and SMTP for sending   alarm e-mails;
• Leakage, capacitance and tangent delta alarms that warn of high values or trends, with local indications and output contacts;
• Modular system: configurable to monitor between 3 and 18 bushings;
• Programmable to operate with spare bushing in event of single-phase transformer banks;
• Protection against opening of bushing taps with intelligent alarm indication  through self-diagnostic;
• Entries for optional temperature  sensors for recording of environmental,  oil or other temperatures;
• Robust design exceeds EMC standards for substation operation under severe electromagnetic conditions. Operating temperature -40  to 85ºC;
• Universal voltage  supply,  from 38  to 265 Vdc or Vac;
• Compact dimensions saves space and reduces control panel costs;