According to the revision of the Low-Voltage Grid Interconnection Regulations in April 2024 in Japan, three-phase PV inverters used in low-voltage interconnection projects (including deemed low-voltage interconnection) must be compatible with the new active method “frequency feedback method with step injection (STEP3.2).

Frequency feedback method with step injection in Japan:
Link (Japanese version): https://www.jema-net.or.jp/Japanese/res/dispersed/data/s06.pdf
Source: The Japan Electrical Manufacturers’ Association (JEMA)

Specifications of technical requirements:
Link (Japanese version): https://www.jema-net.or.jp/Japanese/res/dispersed/data/pcs_standard_specification.pdf
Source: The Japan Electrical Manufacturers’ Association (JEMA)

In this column, we introduce the status of each manufacturer’s support for three-phase PV inverters as of the end of February 2024.

(Note: This information has been compiled by our company. Please check with the manufacturers or suppliers for correctness and details.)

1. DIAMOND & ZEBRA ELECTRIC MFG. CO., LTD.

• Model: EPG-T99P5 (Three phase 9.9kW)
  Software and product release date for the new active method: August 2024 (planned)
  The EPG-T99P5 (Revision) model does not have JET certification, so the interconnection consultation will be handled on a case-by-case basis.
• Model: EPD-T250P6 / EPD-T330P7 (Three phase 25kW, 33.3kW)
  No plans to support.

2. SANYO DENKI CO., LTD.:

• Model: P73J992RFC / P73J103RFC (Three phase 9.9kW, 10kW)
  Orders start: Middle of march 2024.
  Specifications and technical descriptions can be submitted. Characteristic data to be submitted by the end of February 2024.
• Model: P73L103S / P73L103P (Three phase 10kW, 10kWunit model)
  Scheduled to be applied from around June 2024. 10 kW units can be stacked in an input/output box to accommodate output capacities from 10 to 60 kW.
• Model: W77A992R / W77A992S (Three phase 9.9kW, for Wind/Hydro)
  Specifications and technical descriptions to be submitted by the end of February. Characteristic data to be submitted end of March 2024.
• Model: P73H103SFC (Three phase10kW, with off-grid operation mode)
  No plans to support.
• Other models not listed (discontinued products)
  No plans to support.
• New products for low-voltage interconnection
  All are planned to be supported.

3. YASKAWA ELECTRIC CORPORATION:

• Model: CEPT-P2HA29P9 (Three phase 9.9kW, High-frequency insulation)
  Scheduled to be supported. Supported models are not subject to JET certification.
• Model: CEPT-P2AA29P9 / CEPT-P2AA2010 (Three phase 9.9kW, 10kW, transformerless)
  No plans to support.
• Model: CEPT-P3AA2025B / CEPT-P3AA2025B (Three phase 25kW, standard model, multi-function model)
  No plans to support.

4. Huawei Technologies Co., Ltd.

• Model: SUN2000-20KTL-M3 (Three phase 20kW)
  Scheduled to be supported.
• Model: SUN2000-33KTL-NH / SUN2000-40KTL-NH (Three phase 33.3kW、40kW)
  Scheduled to be supported.
• Model: SUN2000-50KTL-JPM0 / SUN2000-50KTL-NHM3 (Three 50kW)
  No plans to support.

5. Sungrow Power Supply Co., Ltd.

• Model: SG49.5CX-JP (Three 49.5kW)
  No plans to support.

6. GS Yuasa International Ltd.:

• Model: LBSK-10-T3C (Three phase 10kW)
  To be informed.

Following the revision of the Low Voltage Grid Interconnection Rules in April 2024, “Application of Allowable Frequency in Parallel” is scheduled for facilities in both high-voltage and low-voltage interconnection next April 2025. The following is a reprint of material from Sanyo Denki Co., Ltd.

If power generation facilities are paralleled when the grid frequency is rising beyond the appropriate range, it will contribute to a further rise in frequency and may significantly disrupt the stability of the commercial power system. Therefore, it is necessary for power generation facilities to be equipped with a device or function to confirm that the system frequency is less than the allowable frequency in parallel (standard frequency + 0.1 Hz).

<Note>
・If the start date of grid interconnection is after the start date of application of the allowable frequency in parallel, products that do not meet the requirements will not be allowed to be connected to the grid. If you use products that do not meet the requirements, please plan to complete the interconnection before the start of application of these requirements.
・Please note that existing power generation facilities are also subject to this requirement if they are replaced due to malfunction or other reasons.

We will plan to introduce the “Allowable Frequency in Parallel” from April 2025 in our column at a later date.