As a vital pillar of traditional manufacturing, the textile industry involves multiple production stages—spinning, weaving, dyeing, and finishing—each of which depends on a stable and reliable power supply. Textile machinery, lighting systems, air‑conditioning equipment, air compressors, water pumps, and other auxiliary devices all require continuous, high‑quality electricity. The transformer, as the “heart” of the entire power distribution system, directly affects production efficiency, equipment lifespan, and operating costs if chosen incorrectly.
So, how should textile enterprises select transformers scientifically? This article provides a complete guide, covering industry standards, selection essentials, product recommendations, and installation and maintenance advice.
Before delving into transformer selection, it is essential to understand the load characteristics of the textile sector:
Continuous operation with high load factors – Textile equipment is mostly continuous‑duty, with high installed capacity and long running hours, accounting for a significant share of total plant energy consumption.
Large number of inductive loads – Spinning frames, air‑jet looms, dyeing machines, etc., extensively use electric motors, demanding high power stability.
Pronounced harmonic pollution – As textile machinery automation increases, variable‑frequency drives (VFDs) are widely used for speed regulation and energy saving. However, they generate substantial harmonics that contaminate the grid and threaten the safe and stable operation of the power system.
Challenging environmental conditions – Textile workshops often experience high temperature, high humidity, and airborne dust, imposing stricter requirements on transformer protection and reliability.
Transformer capacity selection must consider the simultaneous operation coefficient (typically 0.7–0.8 for textile processes), the demand coefficient (0.6–0.8 for motor‑based equipment), and a 15%–20% margin for future production expansion.
A practical estimation method: first sum the nameplate power of all equipment, then factor in power factor and safety margins. The simplified formula is:
Transformer capacity (kVA) = Total equipment power (kW) / 0.8 (power factor) × 1.2 (safety factor)
According to the Code for Design of Cotton Textile Plant (GB/T50481‑2019), the total capacity, unit capacity, and number of transformers should be determined based on calculated loads and economic operation principles; the unit capacity should not exceed 3150 kVA. For cotton spinning mills, the typical transformer capacity per 10,000 spindles is in the range of 1000–1200 kVA.
Load factor is another critical parameter. To reduce no‑load losses, no‑load current, and noise, the load factor should preferably be 60%–80%. In regions where monthly basic electricity charges apply, a slightly higher load factor is acceptable but should still not exceed 85%. A reasonable load factor not only lowers basic electricity costs but also extends transformer service life.
The Code for Design of Cotton Textile Plant explicitly states: transformers should adopt the D,yn11 connection group.
Why is D,yn11 so important? Because the delta (△) connection on the primary side provides a path for 3rd‑harmonic currents, generating counteracting harmonic currents and fluxes on the secondary side, effectively mitigating the harmful effects of 3n‑order harmonics caused by grid pollution. Given the extensive use of VFDs and other non‑linear loads in textile workshops, choosing the D,yn11 connection group is a fundamental measure for harmonic suppression and power quality assurance.
When selecting transformers for textile applications, the main choice is between dry‑type and oil‑immersed units:
Dry‑type transformers offer higher safety and environmental friendliness due to their oil‑free design, eliminating fire and leakage risks. They are particularly suitable for installation in auxiliary rooms adjacent to workshops and can be placed in the same room as switchgear. With simple construction and low maintenance costs, dry‑type transformers are increasingly favoured in the textile industry.
Oil‑immersed transformers still have advantages for large‑capacity applications, covering a wide rating range (50 kVA to 3000 kVA) and excelling in voltage transformation and power transmission. However, they require a separate transformer room.
For most textile enterprises, dry‑type transformers are the preferred option, especially in environments with high temperature, high humidity, and dust.
Under China’s “dual carbon” targets, the textile industry is identified as a key sector for energy conservation and upgrading. The national standard GB 20052‑2020 Minimum allowable values of energy efficiency and energy efficiency grades for power transformers sets stricter limits on no‑load and load losses.
Creating a green textile factory requires that the no‑load and load losses of 11 kV and 35 kV distribution transformers meet at least Grade 2 energy efficiency. For example, the commonly used SCB‑1600/10‑NX2 dry‑type transformer for textile workshops has no‑load and maximum load losses not exceeding 0.645 kW and 1.132 kW respectively.
Although selecting a higher‑efficiency transformer may involve a slightly higher initial investment, the long‑term electricity savings are considerable. One case study shows that a textile plant saved approximately RMB 2 million annually in electricity costs after adopting high‑efficiency dry‑type transformers.
With numerous VFDs in textile workshops, harmonics—when amplified by low‑voltage capacitor banks—can cause busbar overheating and substation temperature rises. Besides choosing the D,yn11 connection group, it is advisable to install passive filtering and detuned reactor combinations on the low‑voltage busbar in the workshop substation. For severe harmonic pollution, active power filters (APF) can be added for dynamic compensation.
As a large enterprise integrating R&D, manufacturing, trade, and service in the industrial electrical equipment sector, Jiangsu Xinhong Electrical Equipment Co., Ltd. has been dedicated to providing safe, efficient, and environmentally friendly power solutions for the textile industry and beyond.
Xinhong Electrical’s core product portfolio includes:
Epoxy Resin Cast Dry‑Type Transformers – This is Xinhong’s flagship product line, featuring advanced epoxy resin casting technology that offers oil‑free, fire‑resistant, non‑polluting, and low‑noise advantages. Capacities range from 100 kVA to 25000 kVA, with voltage ratings covering 11kV, 20 kV, 22 kV, 30 kV ，33 kV and others. The core is made of high‑quality cold‑rolled grain‑oriented silicon steel, and the windings adopt foil‑wound (low voltage) and segmented layer (high voltage) structures to effectively reduce losses and enhance short‑circuit withstand capability. For the harsh conditions of textile workshops—high temperature, high humidity, and dust—the epoxy resin cast dry‑type transformer provides excellent protection.
Oil‑Immersed Distribution Transformers – For textile plants requiring large capacities, Xinhong offers three‑phase oil‑immersed transformers from 50 kVA to 3000 kVA. These products feature high stability and reliability, with a fully sealed design to extend service life.
Customisation Services – Xinhong Electrical supports tailored solutions based on the actual operating conditions of textile enterprises, whether for special voltage combinations, connection groups (Dyn11), or specific protection ratings.
Choosing the right transformer is only the first step; correct installation and proper maintenance are equally important:
Installation: Dry‑type transformers should be installed in a well‑ventilated, dry indoor location. Sufficient space should be reserved around the transformer for heat dissipation and maintenance—generally, at least 1 metre on all sides. Wiring and earthing must strictly follow specifications to avoid faults caused by improper installation.
Maintenance: Periodically inspect the transformer for visible abnormalities and clean dust accumulation from the surface to ensure cooling efficiency. Maintain operating logs and analyse data to detect anomalies early. For special environments like high‑temperature, high‑humidity dyeing workshops, consider specifying moisture‑proof transformer variants.
Transformer selection for the textile industry is a systematic process that requires comprehensive consideration of capacity calculation, connection group, equipment type, energy efficiency, harmonic mitigation, and other factors. Choosing Xinhong Electrical high‑quality transformer products not only ensures a stable and reliable power supply for your textile plant but also helps you achieve energy savings, cost reduction, and green manufacturing goals.
Whether you are building a new textile factory or upgrading an existing distribution system, Xinhong Electrical’s professional team can provide full‑spectrum support—from selection consulting to after‑sales service. Contact us today for a customised transformer solution tailored to your plant’s specific needs.
