Grid battery storage electronics for Canada need an AC-side surge rung that fits the system voltage, and the Walsin Technology (Walsin) varistor ladder has no 600 Vac step: 3 part numbers at 575 Vac, 13 at 625 Vac. Ontario’s IESO reported on 19 June 2026 that it had contracted 640 MW of new battery storage.
Venatech Limited, an authorised Walsin distributor in Hong Kong, wrote this for a Canadian power-conversion or storage-system design engineer choosing a disc varistor for an AC port. The market statement is sourced and dated. The counts come from the Walsin MOV export, file Walsin_MOV_ALL.xlsx (379 part numbers), and our ready-stock snapshot as at 23 September 2026. We do not know your system voltage, and nothing here says what one is. Every part number is real.
What did Ontario’s IESO announce about battery storage in June 2026?
On a page published 19 June 2026, the IESO reported that the capacity stream of the first window of its Long-Term 2 procurement contracted 640 MW from three new-build battery storage facilities on 20-year contracts, in northern, south-western and eastern Ontario.
The page adds that Ontario’s battery storage is expected to exceed 3,500 MW by 2030 and calls Long-Term 2 the largest electricity system procurement in the province’s history, with more windows planned. Those are the IESO’s statements, not ours. We know nothing of who builds the power electronics for these sites and make no claim about any named company.
Why does the Walsin varistor ladder skip 600 Vac?
We counted the Walsin MOV export and found 82 part numbers rated 460 Vac or higher, spread over eight working-voltage rungs; none is rated exactly 600 Vac.
The nearest are 3 part numbers at 575 Vac and 13 at 625 Vac. If your converter or transformer port is a 600 V class system, the 575 rung sits below it and the 625 rung is the first that clears it. Whether 625 Vac is the right margin is your design decision, not our claim.
| Working voltage rung | Part numbers | Peak current range | Match / mismatch with a 600 Vac brief |
|---|---|---|---|
| 460 Vac | 13 | 2,500 to 80,000 A | Mismatch with a 600 Vac brief: below 600 |
| 485 Vac | 13 | 2,500 to 80,000 A | Mismatch with a 600 Vac brief: below 600 |
| 510 Vac | 13 | 2,500 to 80,000 A | Mismatch with a 600 Vac brief: below 600 |
| 550 Vac | 13 | 2,500 to 80,000 A | Mismatch with a 600 Vac brief: below 600 |
| 575 Vac | 3 | 40,000 to 80,000 A | Mismatch with a 600 Vac brief: below 600 |
| 625 Vac | 13 | 2,500 to 80,000 A | Match on voltage |
| 680 Vac | 13 | 2,500 to 80,000 A | Match on voltage |
| 750 Vac | 1 | 70,000 to 70,000 A | Match on voltage; one part, 53 mm only |
We have not seen this ladder laid out anywhere else. Our post on anti-surge chip resistors covers the resistor side of surge design.
Which Walsin varistors clear a 600 Vac, 10,000 A brief?
15 of the 379 Walsin varistor part numbers meet both a working voltage of at least 600 Vac and a peak current of at least 10,000 A. The brief is an example, not a design: set your own voltage and energy.
The table puts six real parts against it, including two that pass on voltage and fail on current, which is the trap in a 625 Vac rung where the small discs carry 2,500 to 9,000 A.
| Walsin part | Series, size, working voltage, varistor voltage, peak current | On shelf 23 Sep 2026 | Match / mismatch with a 600 Vac, 10,000 A brief | Your incumbent |
|---|---|---|---|---|
SR102K25D |
Standard (D Series), 25mm, 625Vac, varistor voltage 1000Vdc, 18000A peak | No | Match: 625 Vac is above 600 and 18000 A clears 10,000 A | |
SR102K20E |
Super High Energy (V Series), 20mm, 625Vac, varistor voltage 1000Vdc, 13000A peak | No | Match: 625 Vac and 13000 A | |
SR102K18E |
High Energy (E Series), 18mm, 625Vac, varistor voltage 1000Vdc, 9000A peak | No | Mismatch: 625 Vac passes but 9000 A is below 10,000 A | |
SR102K20D |
Standard (D Series), 20mm, 625Vac, varistor voltage 1000Vdc, 6500A peak | No | Mismatch: 625 Vac passes but 6500 A is below 10,000 A | |
SR951K34R |
Industrial, 34mm Square, 575Vac, varistor voltage 950Vdc, 40000A peak | No | Mismatch: 575 Vac is below 600 even though 40000 A is ample | |
SR122K53D |
Industrial, 53mm, 750Vac, varistor voltage 1181Vdc, 70000A peak | No | Match on the electrical fields; mismatch in size: 750 Vac, 53 mm, 70000 A |
A match here is a match on export fields only. Confirm against both datasheets (we hold no varistor datasheet; see the varistor range) and qualify in your own circuit.
Is any Walsin varistor on the Hong Kong shelf?
No: 0 of 379 varistor part numbers appear in our stock snapshot as at 23 September 2026. Every part in the table is a to-order enquiry.
The ready stock list is a dated snapshot, never live-synced, and we state no lead time or quantity. If your design needs a surge rung quickly, send the working voltage, peak current and disc size you can accept, and we will return the candidates. Disc size sets the board space, so the 53 mm part is a mechanical decision before it is an electrical one.
What will we not tell you about Canadian storage projects?
We will not tell you your system voltage, your surge category or which varistor your inverter needs. We hold 28 Walsin datasheets, 451 pages, and none covers a varistor, so every figure here is catalogue data from the MOV export, not a rating we have read in a datasheet.
We hold no ISO 9001 or IATF 16949 certificate and claim no office, entity or stock in Canada; our locations are Hong Kong, Shenzhen, Singapore and Jiangmen, with Chengdu in preparation. We give no legal, customs or conformity advice. Confirm with your compliance team.
How can Venatech help a Canadian storage-system buyer?
How Venatech helps starts with a free paste box. Our VenaMatch tool at /cross-reference/ decodes 18 manufacturers’ part numbers, covers 800,000+ crossable parts, takes up to 500 part numbers or an Excel or CSV file, and marks every field match or mismatch. Upload a board list at /bom/ and read the ready stock snapshot dated 23 September 2026.
Worked example from our own export: a 600 Vac, 10,000 A brief returns 15 of 379 varistors, none on the shelf, and a 575 Vac part that fails on voltage by 25 V. Walsin is the only line we are authorised for; Stackpole and Viking are lines we supply. We work from Hong Kong, welcome small lots, and you request a quote through the site. We give no legal, customs or conformity advice; confirm with your compliance team, and qualification stays with you.
The short version
Ontario’s IESO reported 640 MW of contracted battery storage on 19 June 2026. For the AC port, the Walsin varistor ladder runs 550, 575, 625 and 680 Vac with no 600 Vac step, 15 of 379 part numbers pass a 600 Vac, 10,000 A example brief, and none is on our shelf.
Send us the varistor line from one storage-converter board list, with the working voltage, peak current and disc size you accept, and we will return the Walsin parts with every difference stated. Does your system voltage sit between two rungs?
Sources (fetched 10 November 2026)
- Independent Electricity System Operator (Ontario), Long Term 2 Capacity Stream Results Announced, published 19 June 2026: https://ieso.ca/Sector-Participants/IESO-News/2026/06/June-18—Long-Term-2-Capacity-Stream-Results-Announced
- Walsin MOV export Walsin_MOV_ALL.xlsx and Venatech ready-stock workbook (.xlsx) as at 23 September 2026, re-measured 10 November 2026 (internal files).
Related reading
- Anti-surge chip resistors
- How to cross-reference an MLCC, field by field
- Walsin passive components held in Hong Kong
- Free cross-reference tool (VenaMatch)
- Ready stock, Hong Kong snapshot dated 23 September 2026
Last reviewed 10 Nov 2026.
Frequently asked questions
What did the IESO announce on battery storage in June 2026?
A page published 19 June 2026 reports 640 MW of battery storage contracted from three new-build facilities on 20-year contracts in the first window of Long-Term 2, and expects Ontario storage to exceed 3,500 MW by 2030.
Does Walsin make a 600 Vac varistor?
Not as a listed working voltage. The MOV export has 575 Vac (3 parts) and 625 Vac (13 parts) but no 600 Vac step. Whether either suits your system is your design decision.
Which Walsin varistors pass 600 Vac and 10,000 A?
15 of 379 part numbers pass both example limits, for instance SR102K25D at 625 Vac and 18000 A. Set your own limits, confirm against the datasheet and qualify in your own circuit.
Is a Walsin varistor on the Hong Kong shelf?
No. 0 of 379 varistor part numbers are in the snapshot dated 23 September 2026. Every part is a to-order enquiry, with no lead time or quantity stated.
Does Venatech have an office or stock in Canada?
No. Our locations are Hong Kong, Shenzhen, Singapore and Jiangmen, with Chengdu in preparation. We serve Canadian buyers from Hong Kong, in small lots, with a quote requested through the site.
Is Venatech authorised for Walsin only?
Yes. Venatech is authorised for Walsin only. Stackpole and Viking are lines we supply. We give no legal, customs or conformity advice; confirm with your compliance team.