AT&C losses means Aggregate Technical and Commercial losses. It is a utility metric that combines two kinds of loss in a power distribution network: technical loss from heat, overloads, and inefficient equipment, and commercial loss from theft, meter tampering, billing errors, and non-collection. The number tells operators how much electricity is disappearing before it is fully measured and paid for.
In cyber security, AT&C losses matter because modern grids depend on data integrity. Smart meters, remote readings, feeder monitoring, and billing systems can reveal abnormal loss patterns, but they also create new attack surfaces. Attackers may try to spoof meter data, tamper with telemetry, or exploit weak access controls to hide illegal tapping or fraud. Defenders use tamper-resistant meters, segmentation, authenticated communications, and anomaly detection to separate physical faults from manipulation. In practice, AT&C loss reduction is both an engineering task and an information-security problem.