New National Standard for Distribution DTUs: Hardware Encryption Becomes a Mandatory Threshold

On July 1, 2026, GB/T 35732-2025, the Technical Specification for Distribution Automation Terminals, officially took effect. This is not a routine standard revision. The new version completes a systematic reconstruction — from product architecture to performance metrics — around three trends: distributed power integration, distribution grid digitalization, and power security protection.

For designers and procurement teams of distribution DTUs/FTUs, the most direct change is this: all four technical upgrades point to the hardware level. Pure software upgrades can no longer pass type testing.

Four Mandatory Upgrades, All Pointing to Hardware

According to technical interpretations from the standard's drafting organizations, the new national standard brings four key changes:

SOE accuracy requirement ≤2ms. A general-purpose Linux kernel struggles to guarantee deterministic response; an RTOS real-time core is needed to provide deterministic timestamps. This means the processor architecture must be reconsidered.

Information security mandates a hardware cryptographic module. Pure software encryption solutions are no longer compliant. Identity authentication, data integrity, and confidentiality protection must be implemented through hardware cryptographic modules or chips.

Satellite timing synchronization accuracy better than 1ms. This requires IRIG-B decoding and real-time clock management capabilities, providing a time reference for high-precision applications such as distributed FA and fault traveling wave ranging.

Edge computing requires multi-core compute power. Functions such as fault recording and small-current grounding detection place explicit demands on processor compute capability.

In addition, Table 1 of §7.1.1.1 specifies that outdoor DTU/FTU units are subject to Class C2 operating temperatures (-40°C to +70°C). Commercial-grade chips cannot pass environmental testing.

An Easily Overlooked Constraint: Domestic Content Ratio

Beyond the technical requirements of the new standard, there is an "invisible threshold."

State Grid requires that by the end of 2026, the domestic content ratio of distribution terminals reach 95%, and core board chips must provide domestic certification reports. This means that during selection, you must not only look at technical parameters but also at the "identity" of the chip.

Some mainstream solutions may meet functional requirements, but if the core chip cannot provide domestic certification, the entire unit will get stuck at the type-testing stage.

A Technology Iteration Window in a 1.2 Million-Unit Market

The annual market of 1.2–1.3 million DTU/FTU units is standing at the starting point of a technology iteration.

For equipment manufacturers, this is a moment that demands a choice: continue patching up old platforms, or take advantage of the standard switch to redesign products?

From an actual engineering perspective, selection requires answering several specific questions:

How to choose the processor architecture? SOE accuracy and edge computing requirements point toward heterogeneous multi-core solutions — for example, an "application core + real-time core" architecture, where the real-time core handles deterministic timing tasks and the application core handles protocol stacks and algorithms.

How to integrate the hardware encryption module? This is a mandatory requirement of the new standard. During selection, you must confirm whether the chip or module supports domestic cryptographic algorithms (SM2/SM3/SM4) and whether mature integration solutions exist.

How to configure network ports? In actual deployment of distribution DTUs/FTUs, the three-port requirement for southbound collection, northbound reporting, and local O&M is not uniform. Two-remote and quasi-three-remote units may only need two ports. What matters in selection is "can it be combined on demand," not "how many ports maximum."

Is there domestic certification? This is a hard condition that must be confirmed in advance — it cannot be added later.

From Chip to Complete Unit: The Compliance Path for Communication Terminals

Once the processor and core board selection is determined, the communication reliability and environmental adaptability of the DTU unit are equally critical.

Take the MovingComm D220 series DTU as an example. The design approach of this product has gained attention in some distribution automation projects. Several points in its specification table are worth comparing against the new national standard:

Wide-temperature design covers Class C2 requirements. Operating temperature range of -35°C to 75°C, storage temperature of -40°C to 85°C, basically covering the temperature requirements of outdoor scenarios under the new standard. Metal casing with IP41 protection rating, suitable for installation environments inside distribution cabinets.

Dual serial channels adapt to legacy equipment. Supports RS232 and RS485 standard interfaces. For the large number of serial devices in distribution automation (multi-function meters, protection devices), it enables plug-and-play, reducing retrofit workload.

Software and hardware watchdog ensure unattended operation. Device fault self-recovery and automatic reconnection after network loss — in scenarios like distribution terminals that are "installed and then forgotten," these functions directly relate to O&M costs.

Cloud platform management supports large-scale deployment. Supports remote device status monitoring and fault alerts. For dispersed DTU installations, centralized management capability can reduce on-site inspection frequency.

From a compliance perspective, the D220's wide-temperature and dual-serial design matches the new standard's requirements for outdoor environmental adaptability. The integration of the hardware cryptographic module needs to be confirmed according to specific project solutions. During selection, it is recommended to directly request relevant technical specifications and certification information from the manufacturer.

Final Thoughts

The implementation of the new national standard is essentially pushing distribution terminals from "capable of collecting data" to "capable of collecting data securely and reliably."

For equipment manufacturers and integrators, the selection logic needs to shift from "what protocols does this DTU support" to "can this DTU pass 2026 type testing."

Hardware encryption, industrial-grade chips, domestic certification, multi-core compute power — these are not bonuses; they are the passing grade. With a 1.2 million-unit market standing at the iteration starting point, manufacturers that switch technology early will earn their entry ticket for the next round of tenders.