{"id":7225,"date":"2026-01-05T08:01:17","date_gmt":"2026-01-05T08:01:17","guid":{"rendered":"https:\/\/daelimtransformer.com\/?p=7225"},"modified":"2026-01-14T15:59:42","modified_gmt":"2026-01-14T15:59:42","slug":"the-primary-guide-of-delta-star-transformer","status":"publish","type":"post","link":"https:\/\/www.daelimtransformer.com\/de\/delta-star-transformer.html","title":{"rendered":"Der Hauptf\u00fchrer des Delta-Star-Transformators"},"content":{"rendered":"
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Do you know anything about Star Delta transformers? This article will introduce the definition of delta star transformer, its advantages and disadvantages, application, calculation formula, and the reason for using this connection.<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/p>\n

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<\/span><\/a>The difference between star connection and delta connection<\/span><\/span><\/span><\/span><\/b><\/span><\/span><\/span>\"delta-transformer\"<\/span><\/h2>\n

The common transformer winding has two kinds of connection, namely “delta connection<\/a>” and “star connection”.<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/p>\n

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The difference between star connection method and triangle connection method of transformer: whether there is neutral point, third harmonic and zero sequence current in the fluidity of triangle, different current voltage, different applicability.<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/p>\n

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1. There is no neutral point:<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/p>\n

Star connection (Y) connection can be derived from the neutral point; The triangle (D) connection cannot lead to a neutral point.<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/p>\n

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2. Third harmonic and zero sequence current flow in triangle:<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/p>\n

Star connection (Y) connection third harmonic and zero sequence current can not flow in the internal; Triangle (D) connects the third harmonic wave and the zero-sequence current can flow in the triangle, and has no influence on other coils.<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/p>\n

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3.Current and voltage<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/p>\n

Star connection (Y) connection method: line current and phase current equal; The line voltage is square root of 3 of the phase voltage; There are two kinds of voltage values, there are zero lines, such as 380V and 220V two kinds of voltage.<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/p>\n

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Triangle (D) connection: line voltage is equal to phase voltage; The line current is square root of 3 of the phase current; There is only one voltage, no zero line.<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/p>\n

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4. Applicability:<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/p>\n

Star (Y) connection: generally used for distribution network output, easy for users to select voltage.<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/p>\n

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Triangle (D) connection: generally used for power network transmission.<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/p>\n

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Learn\u00a0more :<\/span>\u00a0Basic Guide Of Delta Transformer<\/span><\/a><\/span><\/strong><\/p>\n

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<\/span><\/a>Why do we use delta-star in transformer?<\/span><\/span><\/span><\/span><\/b><\/span><\/span><\/span><\/span><\/h2>\n

The delta connection on the low-voltage side of the main transformer serves to eliminate third harmonics, preventing them from distorting the power grid voltage waveform. A notable characteristic of third harmonics is their phase alignment, which allows them to circulate effectively within the delta configuration, thereby attenuating their transmission to the system and ensuring quality power supply. Additionally, zero-sequence currents can circulate in the delta connection when the neutral point is directly grounded on the high-voltage side of the main transformer, preventing potential malfunctions in low-voltage side zero-sequence protection affecting the superior power grid.<\/span><\/p>\n

On the other hand, the star connection on the high-voltage side of the main transformer aims to reduce line losses and current, improve neutral point grounding, and minimize non-ferrous metal requirements. The low-voltage side is delta-connected primarily for its ability to attenuate third harmonics.<\/span><\/p>\n

In transformers, one side of either the primary or secondary windings is typically delta-connected to provide a path for third harmonic currents, ensuring induced potentials remain sinusoidal and avoiding distortion. This delta-connected winding serves a similar purpose whether on the primary or secondary side.<\/span><\/p>\n

However, for insulation material efficiency, the high-voltage side is commonly star-connected, while the low-voltage side is delta-connected.<\/span><\/p>\n