The purpose of the continuous on line diagnostics is to highlight incipient problems before these can cause power system outage with the goal of better handling maintenance intervention. In order to achieve this goal it is necessary to set up a continuous monitoring system: any further off line tests with dedicated test equipment can be programmed depending on the actual apparatus conditions.
ISA has developed EDS – Expert Diagnostic System for the continuous monitoring of HV substation devices and CB Monitor for HV and MV circuit breakers.
EDS – EXPERT ON LINE DIAGNOSTIC SYSTEM FOR HV SUBSTATION EQUIPMENTS
EDS units are designed to continuously monitor the condition of:
• High Voltage and Medium Voltage Circuit Breakers.
• Current and Voltage Transformers.
• High Voltage Surge Arrestors (MOV’s).
The EDS is easy to install and, once configured, operates continuously. EDS units are designed to operate reliably under extreme weather conditions and electrical interference found in normal substation operations. In particular:
• Modules mounted outdoor are IP 65 and designed to work over an extended temperature range (from – 40°C to + 85°C).
• Self-diagnostics continuously tracks the condition of the EDS and issues alerts if an abnormality is detected in the system.
• By the continuous monitoring of the key parameters, EDS detects malfunctions in early stage and issues prioritized alarms communicating abnormal conditions and guiding maintenance decisions.
CB MONITOR – ON LINE CIRCUIT BREAKER MONITORING SYSTEM
ISA has also developed CB MONITOR system, a cost-effective on line diagnostic system specifically designed to monitor up to 10 MV and HV circuit breakers simultaneously. CB MONITOR verifies continuously the following parameters:
• Auxiliary contacts opening and closing time;
• Auxiliary contacts bouncing times;
• SF6 Density trend (optional);
• Temperature (optional);
• Accumulated fault current during arcing time (I2t);
• Open and close current profiles;
• Mechanism operating time (optional);
• Battery voltage.
All the measurements performed by the monitoring devices are delivered to the system using the following international standard communition protocols:
. IEC standard 60870-5-104 (IEC standard 60870-5-101 optional) communication protocol
. DNP3 communication protocol
The operating system of the computing unit is based on the Windows CE platform.
The basic characteristics are:
. Execution of the monitoring of the various peripheral units
. Storage of the results in daily/weekly/yearly database that can be simply consulted
. Trend analysis of the SF6 density.
. Possibility to modify the threshold parameters.
. Possibility to remotely configure thresholds, zeroing measurements and so on.
. Firmware Upgrade of the various peripheral units
. Remote interrogation from another PC via static IP (with password)
. Transmission of the measurements and the alarms to the monitoring unit (U.M.) of the MRE system
EDS and CB MONITOR systems verify continuously parameters. Then, the monitoring system through its software processes and manages the acquired data and automatically sends alarm messages to the central SCADA if thresholds are exceeded. The software can process and analize the data and automatically can detect and report in details the origin of the problem (electrical, mechanical, aging or due to gas leakage), without the need of the operator’s analysis.