Wind Farm Electronics for Portugal from Hong Kong: 5,965 MW Connected at End-2025 and 1 of 379 Walsin Varistor Rows Clears a 690 V Line-to-Line Supply, None on the Shelf

Wind farm electronics for Portugal start from the supply voltage, not the surge rating. We parsed all 379 Walsin Technology (Walsin) varistor rows: 82 clear a 440 V working stage, the first rung is 460 Vac, and only 1 row, a 53 mm disc at 750 Vac, clears a 690 V line-to-line supply. None is on our shelf.

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Venatech Limited, an authorised Walsin distributor in Hong Kong, holds the Walsin varistor export and a stock list dated 23 September 2026. This post is for a maintenance, retrofit or control-cabinet engineer at a Portuguese wind operator, service company or board maker who needs a component-level varistor candidate. Every part number is real and every count is ours. The market and voltage statements name their sources and the day we fetched them, 23 October 2026.

What does Portugal’s wind fleet look like at the end of 2025?

Large, ageing in places, and growing slowly. A report by INEGI and APREN with a December 2025 cut-off lists 5,965.0 MW of grid-connected wind with 2,861 turbines, plus 446.8 MW and 75 turbines under construction; of that new capacity about 80 percent is new projects, 14 percent repowering and 6 percent over-equipment. The report says capacity additions stagnated again in 2025.

Fourteen percent of 446.8 MW is about 63 MW of repowering by our arithmetic. The same report cites the national energy and climate plan’s 2030 foresight of 10.4 GW onshore and 2.0 GW offshore. Mainland Portugal holds 5,833.6 MW of the connected total, Madeira 63.8 MW, the Azores 42.6 MW and offshore 25.0 MW.

We use these figures for one purpose: an installed fleet of thousands of turbines needs spares and repaired control boards for years, and repowering adds new ones. We have no relationship with any Portuguese operator or turbine maker, we know nothing of any bill of materials, and we name none.

Which supply voltages do turbine electronics sit on, and where do the Walsin varistor rungs fall?

On a 400/690 V system, the rung choice splits in two. A surge-protection vendor’s article of 11 October 2007 puts the generator voltage at 690 V, the supply level at 400/690 V and the continuous operating voltage of its arresters at 440 V; against that, Walsin’s ladder has 82 rows at 440 Vac or more, a first rung at 460 Vac, and 1 row of 379 at 690 Vac or more. The article also says its Class II arresters are built on metal-oxide varistors.

We read the Max Working Volt. column of every row. The ladder steps 390, 420, 460, 485, 510, 550, 575, 625, 680 and 750 Vac above the mains range, with 13 rows at each of 460, 485, 510, 550, 625 and 680, 3 at 575 and 1 at 750. A stage at 440 V sits between the 420 and 460 rungs, so the 420 rung falls 20 V short and the 460 rung clears it by 20 V. A stage across 690 V line to line clears only the 750 rung, because the 680 rung falls 10 V short. We have not seen this counted anywhere at 690 V. Our posts on the varistor voltage ladder and how to choose a varistor cover the method.

The 2007 article is a vendor’s, almost two decades old, and it describes one design. Your turbine’s voltages are your own; treat the numbers as an example, not a rule.

Which Walsin varistors cross a 440 V and a 690 V stage?

Seven rows show the ladder. Take two briefs, a working stage of at least 440 Vac and a line-to-line stage of at least 690 Vac: the 460 Vac rung matches the first and misses the second, and only SR122K53D at 750 Vac matches both. The sizes and peak currents come from the export.

Walsin part	Max working / varistor voltage	Size / peak current (export)	On shelf 23 Sep 2026	Match / mismatch at 440 Vac	Match / mismatch at 690 Vac	Your incumbent
SR681K14D	420 Vac / 680 Vdc	14 mm Standard D / 4,500 A	No	Mismatch: 20 V short	Mismatch: 270 V short
SR751K14D	460 Vac / 750 Vdc	14 mm Standard D / 4,500 A	No	Match: 20 V above	Mismatch: 230 V short
SR751K53D	460 Vac / 750 Vdc	53 mm Industrial / 70,000 A	No	Match: 20 V above	Mismatch: 230 V short
SR102K14D	625 Vac / 1,000 Vdc	14 mm Standard D / 4,500 A	No	Match: 185 V above	Mismatch: 65 V short
SR112K14D	680 Vac / 1,068.5 Vdc	14 mm Standard D / 4,500 A	No	Match: 240 V above	Mismatch: 10 V short
SR122K53D	750 Vac / 1,181 Vdc	53 mm Industrial / 70,000 A	No	Match: 310 V above	Match: 60 V above

Working voltage is only the first of the fields. The export gives a peak current with no waveform, no energy rating and no clamping voltage for any of the 379 rows, and we hold no varistor datasheet. Confirm against both datasheets and qualify in your own circuit.

What does a Hong Kong shelf hold for a turbine retrofit?

No varistor, and very little of anything it would sit beside. Our 23 September 2026 list holds 1,125 part numbers: 864 MLCC, 254 chip resistor, 1 resistor array, 3 safety capacitor, 2 inductor and 1 other, and 0 varistors. Every varistor in the table is a supply request, not a stock item.

The ready stock list is a dated snapshot, never live-synced, and our post on Walsin passive components in Hong Kong stock covers its scope. See the varistor range for the families. We hold lot and date-code traceability, a certificate of conformity per shipment on request and original sealed Walsin packaging. We serve in small lots, which suits a spares and repair buyer better than a series buyer.

What will we not tell you about lightning protection?

Anything about a protection design. We sell varistor discs, not surge-protective devices; we hold no datasheet for any of the 379 varistor rows, we hold no ISO 9001 certificate, and we make no claim that any Walsin part meets a lightning-protection standard. We hold no office, entity or stock in Portugal.

We give no legal, customs or conformity advice; confirm with your compliance team. Our locations are Hong Kong, Shenzhen, Singapore and Jiangmen, with Chengdu in preparation. Qualification stays with you.

How Venatech helps

Paste your incumbent into the free cross-reference tool, which decodes 18 manufacturers’ part numbers across 800,000+ crossable parts, and read the Walsin candidates with each field marked match or mismatch. Load a whole BOM, up to 500 part numbers or an Excel or CSV file, to run every line of a control cabinet. The ready-stock list is a Hong Kong snapshot dated 23 September 2026.

Worked example from our own export: a 440 Vac brief returned 82 rows and a 690 Vac brief returned 1, and our shelf covers neither. Walsin is the only line we are authorised for; Stackpole and Viking are lines we supply. We serve from Hong Kong in small lots, and you request a quote through the site.

The short version

Portugal has thousands of turbines to keep running and a repowering pipeline to equip. For the varistor in a 400/690 V cabinet, the ladder decides the answer before the surge rating does: the 460 rung clears 440 V, 1 row of 379 clears 690 V, and nothing is on the shelf. The disc is a component; the protection design is yours.

Send us one varistor from a turbine cabinet and the voltage it sees, and we will return the Walsin rows with the margin stated in volts. If the working voltage in your parts list is the only thing you checked, what did you assume about the rest?

Sources

Fetched 23 October 2026.

• INEGI and APREN, “Parques eólicos em Portugal – dezembro de 2025”, data cut-off December 2025: https://www.apren.pt/wp-content/uploads/2026/06/INEGI_APREN-Parques-Eolicos-em-Portugal.pdf
• Machine Design, “When lightning strikes wind turbines”, 11 October 2007, by a surge-protection vendor: https://www.machinedesign.com/news/article/21813288/when-lightning-strikes-wind-turbines

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Frequently asked questions

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