Category Archives: Communication Protocols

GOOSE vs Sampled Values (SV) in IEC 61850: Clear Differences, Use Cases & Engineering Guide

IEC 61850 has transformed how substations communicate. In the past, everything depended on copper wiring, physical contacts, and slow serial links. Today, digital substations use Ethernet-based messages that move information instantly between IEDs. Two of the fastest and most important IEC 61850 services are: Even though both use Ethernet multicast, they serve completely different purposes. GOOSE carries decisions… Read More »

IEC 61850 GOOSE Explained: Complete Guide to Fast Substation Messaging, Protection & Automation

GOOSE (Generic Object Oriented Substation Event) is one of the most important communication services defined in IEC 61850. It is used to exchange fast, event-driven messages between protection IEDs, bay controllers, and automation devices. GOOSE is designed to carry protection signals such as trips, interlocks, blockings, permissives, and alarms with very low latency and high reliability, replacing copper… Read More »

IEC 61850 Data Sets: The Difference Between Static and Dynamic Explained Clearly

Data Sets are one of the most important concepts in IEC 61850. They define which values inside an IED are grouped together so the device can report them, log them, publish them over GOOSE, or return them in a single MMS read request. Anyone working with protection relays, SCADA integration, automation logic, or commissioning eventually deals with Data… Read More »

IEC 61850 MMS Explained: Full Guide to Reporting, Control, and Communication in Digital Substations

IEC 61850 is the modern communication standard used in power utility automation systems. It defines how intelligent electronic devices (IEDs) communicate inside substations and across modern electrical networks. One of the most important technologies inside this standard is MMS (Manufacturing Message Specification). MMS is used for supervisory communication, real-time monitoring, remote control, reporting, configuration, file exchange, and system… Read More »

IEC 61850 Explained: Why It’s Not a Protocol but a Complete Substation Engineering Language

When people first hear about IEC 61850, they often assume it is simply another communication protocol like DNP3, Modbus, or IEC 60870-5-104. But this assumption is incorrect. IEC 61850 is not just a protocol—it is a full engineering language designed to describe, model, and structure the functions that make up modern digital substations and power automation systems. Where… Read More »

Modbus TCP/IP Port 502 (IANA Default Port) — Simple Guide for Real Industrial Systems

In almost every industrial plant today, you’ll find at least a few devices communicating over Modbus TCP/IP—PLCs, power meters, drives, analyzers, and sometimes entire SCADA systems built around it. Even though Modbus is one of the simplest industrial protocols, people still run into problems with connections, firewalls, and port settings. And most of those issues trace back to… Read More »

IEC 60870-5-104 ASDU Structure Explained — Fields and Format

The Application Service Data Unit (ASDU) is the core of the IEC 60870-5-104 communication protocol. It defines how information is represented and exchanged between a controlling station (SCADA master) and controlled stations such as RTUs or IEDs. If the Application Protocol Data Unit (APDU) is the message envelope, the ASDU is the payload — carrying the actual telemetry… Read More »

DNP3 Secure Authentication Version 6 (SAv6): Encryption and Authorization Explained

Modern SCADA and utility automation systems face growing cybersecurity demands. The Distributed Network Protocol (DNP3)—the backbone of many control networks—has evolved to meet them. With the release of IEEE 1815-2020, the DNP3 Secure Authentication Version 6 (SAv6) specification brings authenticated encryption, centralized authorization, and simplified key management directly into the protocol. This article explains how SAv6 improves on… Read More »

DNP3 Port 20000 Explained: Configuration, Security, and Best Practices

In power automation, reliable and secure data exchange between control centers and field devices is critical. One of the most adopted communication protocols that enables this is Distributed Network Protocol version 3 (DNP3). DNP3 communicates over TCP/UDP port 20000, which serves as the standard IP port for linking SCADA master stations with remote field units like RTUs and… Read More »

DNP3 Report by Exception, Background Polls, and Balanced Communication

The Distributed Network Protocol (DNP3) is recognised for its efficiency and reliability in SCADA and power automation systems. The DNP3 protocol is characterized by three key operational concepts: Report by Exception, Periodic Background Polls, and Balanced Communication. These concepts enable the system to optimize bandwidth utilization while ensuring real-time monitoring of field device status. Report by Exception (unsolicited… Read More »