Digital substation system installation in Korea converts traditional substation management — where people judged equipment condition directly — to a smart substation built on digital and communication technology. In a digital substation, intelligent electronic devices (IEDs) exchange monitoring and control signals over a LAN, so communication configuration and testing, rather than copper control wiring, become the core of installation quality. This guide covers two stages: understanding IEC 61850 and installing and testing the system.
Contents
- Common Pre-Work Review
- 1. Understanding IEC 61850 and Related Standards
- 2. Installation and Testing
- Substation Monitoring and Control Methods
- FAQ
- Reference Standards
- Summary
Common Pre-Work Review
Review the IEC 61850 standard, the specification for digitally controlled substation automation (SA) systems, SA manufacturer drawings and manuals, the optical jumper cord specification and installation standard, substation control guidelines and the KEC. Optical jumper cords come pre-terminated, so no field termination is needed, but check the fiber’s optical and mechanical characteristics to choose methods that do not degrade it. Even in a digital substation, AC and DC supplies, CTs, VTs and relay trip circuits still use control cables.
1. Understanding IEC 61850 and Related Standards
- Understand the communication standards and specifications for digital substation systems.
- Test and measure relays and protection equipment for installation.
- Identify the standards needed for interfaces between digital substations.
2. Installation and Testing
- Carry out AC/DC sequence tests, relay interlock tests and SCADA integration tests.
- Confirm the field equipment can be monitored and controlled.
- Test monitoring and control panels (duplex, mosaic, central monitoring) together with SCADA testing.
- Review drawings showing the DC control supply split into two systems so both cannot be lost at once.
- Review protection, alarm and monitoring circuits that protect the DC auxiliary system.
If all DC control supply is lost at once, no relay or breaker can operate. Confirm during testing that the two DC systems are separated as drawn.
Substation Monitoring and Control Methods
| Method | Characteristics |
|---|---|
| Duplex | Operation and metering on the panel front, relays at the back; 1:1 wiring to equipment by feeder or bank |
| Mosaic | Mimic bus and switches on a mosaic-tile panel; 1:1 wiring with control cables |
| Central monitoring | Computer-based monitoring and control linked to a SCADA RTU instead of panels |
| Central monitoring + mosaic | Mosaic panel added so critical equipment can be controlled if the computer or RTU fails |
| Digital substation | Integrated automation with IEDs exchanging signals over a LAN |
This summarizes explanations in the NCS considerations. Actual system architecture follows the project specification.
FAQ
How does a digital substation differ from a conventional one?
Conventional substations wire each device 1:1 with control cables; in a digital substation, IEDs exchange signals over a LAN, so communication setup and integration testing become central.
Are control cables still used in a digital substation?
Yes. According to the NCS, AC and DC supplies, CTs, VTs and relay trip circuits still use control cables.
What is IEC 61850?
The international standard for communication in substation automation, letting devices from different manufacturers exchange information in the same way.
Why split the DC control supply into two systems?
So protection and control keep working if one system fails, preventing simultaneous loss of DC control power.
Reference Standards
- Electricity Business Act (전기사업법) — law.go.kr
- Electrical Safety Management Act (전기안전관리법) — law.go.kr
- Electric Technology Management Act (전력기술관리법) — law.go.kr
- Electrical Construction Business Act (전기공사업법) — law.go.kr
- Occupational Safety and Health Act (산업안전보건법) — law.go.kr
- Korea Electro-technical Code (KEC, 한국전기설비규정) — law.go.kr
- Technical Standards for Electrical Equipment (전기설비기술기준) — law.go.kr
- KEPCO design standards and substation construction practice; Korean Industrial Standards (KS)
- NCS competency unit Digital Substation System Installation (디지털변전시스템 설치, 1901070330_22v2; NCS is Korea’s National Competency Standards) — ncs.go.kr
Summary
The most common mistakes are focusing on wiring checks as in conventional substations while treating SCADA and relay integration tests as a formality, and not confirming that the two DC control systems are separate. Understanding standards depends on IEC 61850 and inter-substation interfaces; installation and testing on sequence, interlock and SCADA tests and DC circuit protection. Related guides: Substation Switchboard Installation, Condition Monitoring System Installation, HVDC Converter Station Construction. A Korean version of this guide is available here.
This article restructures the Korean NCS competency unit ‘Digital Substation System Installation’ (디지털변전시스템 설치, code 1901070330_22v2) as a practical reference. Actual work must follow applicable standards and the judgment of qualified professionals; always confirm specific values, deadlines and criteria against the latest regulations and client standards.
Written/reviewed by VOLT · Last updated 2026-10-26