1. Technical Description

SPD(Surge Protection Device) Disconnector is a device that safely disconnects the SPD from the power system when the SPD fails or reaches the end of its life. According to the IEC 61643-1 standard, the SPD may require a built-in or external disconnector, and its main purpose is to prevent secondary accidents such as fire and explosion.

Key Features

• Overheating Protection : Automatically cuts off the circuit when the internal components of the SPD (e.g. MOV, gas discharge tube, etc.) deteriorate or overheat to prevent further damage.

• Short-circuit protection : If an internal short circuit occurs in the SPD, the isolator will quickly disconnect the SPD to ensure the safety of the power system.

• Fault indication : Many SPD isolators provide visual (e.g. mechanical indicator) indication to the user in the event of a fault.

• Internal/External Installation : The separator can be built into the SPD or installed separately externally. The location and method of installation will depend on the system design and manufacturer’s recommendations.

Standard related requirements (IEC 61643-1, 61643-11, etc.)

• Isolation Function : SPDs must have a isolation function to cut off current and heat in case of a fault, with some exceptions for N-PE (neutral-earth) connections.

• Testing : The IEC 61643-1 standard requires a variety of tests for SPD isolators, including thermal stability, short-circuit current withstand, and electrical insulation. Recent revisions have strengthened isolator technology and test requirements to accommodate complex power environments.

• Multiple protection functions : One isolator can integrate multiple protection functions such as thermal/overcurrent/short-circuit, or have separate isolators for each function.

2. Market Outlook and Technology Trends

• Market Growth : The SPD and separator market is growing steadily due to the increasing complexity of power grids, expansion of renewable energy (especially DC systems), and increasing demand for protection of electronic devices. The global SPD market size was estimated at approximately USD 3.16 billion in 2023 and is expected to continue to grow in the future.

• Technological Advancement : Recent new standards such as IEC 61643-01:2024 have strengthened various technical requirements such as short-circuit current blocking performance, insulation performance, and DC system applicability of the isolator. Accordingly, the design of the internal isolator of the SPD is becoming more sophisticated, and new technologies (e.g. arc extension technology, thermal detection circuit, etc.) are being applied to enable quick and safe blocking in the event of a failure.

• Strengthening safety and reliability : There are increasing demands for testing and certification to ensure the reliability of separators and prevent malfunctions, and in particular, the development of separator technology suited to new power environments such as DC systems is active.

3. Summary Table: SPD Disconnector Key Features and Standard Requirements

4. Conclusion

Separators for SPDs are key components for the safety of power systems, and their technology is continuously evolving in accordance with the requirements of international standards such as IEC 61643-1. In the future, the demand for high-performance separators tailored to new power environments such as renewable energy and expansion of DC systems is expected to further increase.