SDS – Smart Device Expert Disconnector Monitor
Motorized disconnecting switches are used in great quantities insubstations for equipment insulation and operation.
The reliability of the electrical system and the safety of installations depend on switches remaining in good condition and closure and opening operations occurring correctly, especially when remotely controlled.
To achieve this, the SDS Expert Disconnector Monitor performs an online status diagnosis and supervises operations by detecting and identifying unsuccessful operations or confirming normal operations.
Measuring sensors and calculations are conducted in engineering algorithms and the SDS issues alarms in the event of abnormalities, through a colour signalling system that allows a quick view of the disconnecting switch statusas well as launching maintenance warnings based on parameters programmed by the user:
- Green: Disconnecting switch in good condition, no maintenance needed;
- Blue: Disconnecting switch in good condition, but scheduled maintenance is pending;
- Yellow: Alarm for minor abnormality;
- Red: Alarm for more serious abnormality.
The SDS can achieve advanced connectivity including redundant Ethernet ports in fibre optics or RJ-45 and wireless Wi-fi network, as well asIEC-61850, HTTP protocols for embedded web pages, FTP for remote access to files and databases and SMTP to send alarm emails.
In this setup, the SDS operates withembedded SQL databases, facilitating safe and efficient storage, access to historical data and the complete integration with remote online monitoring systems.
Statuses can be linked to SDS output contacts, allowing the remote signalling of disconnecting switch status and the indication of a successful or abnormal operation.
To provide this service, the SDS Disconnecting Switch Monitor supervises several variables online associated with the operation of the equipment, and checks whether they correspond to the typical operation of the equipment under normal conditions. The following measurements are conducted:
- Oscillographs of currents, voltages and power consumed by the motor during operations;
- Reporting of open/closed disconnecting switch contact status;
- Encoder measured displacement of the main contact during operation;
- Control voltage;
- Alarm contacts of motor and/or control circuit protection circuit-breaker activated
- Inside drive mechanism and environmental temperature recording;
- Current level of the drive mechanism’s anti-condensation heater.
To diagnose the switch and its operations, the SDS uses specialized engineering algorithms to correlate these measurements, obtaining useful information for diagnostics and prognosis, such as:
- Signature of consumption and power expended by the motor during operation;
- Motor current at the start of operations;
- Very slow or very fast operation of the disconnecting switch;
- Minimum and maximum motor voltages during operation;
- Total displacement of main contact during operation;
- Coherence between status of disconnecting switch signalling contacts and with the measurement for the main contact position.
- No. of operations and time of the motor has been in service (total and since last maintenance service);
- Time remaining until next maintenance service;
- Mechanism heater operation as a result of temperature;
- Very low or high mechanism activation temperature;
- Control and motor supply under or overvoltage;