Modern electrical substations are managed by intelligent electronic devices communicating through Ethernet-based networks. Because of the highly critical roles of substations, which include safety and protection, electronic devices need to be configured automatically through highly reliable and low-latency networks. This gives substation networks some requirements not addressed by previous industrial network standards. To address these unique challenges, IEC 61850 provides a collection of protocols and a model for the automatic configuration of digital substations. This article briefly overviews this standard and the security efforts to protect substations from attacks.