Implementation of Automatic Demand Management System (ADMS)

The Distribution Companies are required to restrict drawl of power from the grid to comply with the specified frequency requirements so as to overcome any threat to system security in an interconnected system on account of overdrawal from the grid. The Central Electricity Regulatory Commission (CERC) of India mandates manual as well as automatic demand disconnection from the distribution network under overdrawal conditions and on crossing the defined frequency limits. As the manual control at times become ineffective to decrease drawal by a certain quantum within the time limit and hence the automatic demand disconnection scheme assumes significant importance for Distribution Companies operating in developing countries like India to restrict drawl in its control area. The Automatic Under frequency Load Shed (AUFLS) and load relief by rate of change of frequency relay are the defence mechanism whereas Automatic Demand Management System (ADMS) acts as a tool for ensuring security and reliability of the interconnected system. This paper aims to present details of a unique state-of-the-art Automatic Demand Management System (ADMS) implemented for the State Distribution System by the Transmission Utility of the State of Madhya Pradesh in India, which not only disconnects the interruptible loads but also restores the same automatically on clearing the overdrawal conditions. Under this system real time information is gathered through the transmission Supervisory Control and Data Acquisition (SCADA) System and based on logics developed for the scheme, automatic load disconnection & restoration is achieved through the control output of Remote Terminal Unit (RTU) installed for SCADA System of State Transmission network.