Dry type Grounding Transformer

I. About Us

Baoding Tianwei Hengtong Electric Co., Ltd as an owned subsidiary of Tianwei Group, is the backbone software enterprise in Baoding High-tech Development Zone Software Park mainly engaging in power system automation product development, production, sales and service. The company relying on the powerful technology and talent advantages of Tianwei Group has introduced a modern company management mode, with constant innovation committed to provide full-featured, reliable performance and easy to use electric power automation products for the majority of electricity customers.
80% of employees have a bachelor degree or above, with years of practical experience in power system product development and engineering services, and maintain close cooperative relationship with Tsinghua University, Huazhong University of Science and Technology, North China Electric Power University and Hebei University of Technology. A dozen of experts, professors and doctors engaging in the power system has provided a strong technical support for the development of the company's products. The company fully implement the ISO9001 quality assurance system, always adhere to the quality policy "Stable and reliable, quality first", advocating "People-oriented, integrity and sharing" enterprise culture, poly-class talent, first-class products, enhance the reliability of the power level of automation and electrical systems with High-tech automation products.

II. Product performance

THT-DKS (C) series grounding transformer, as three-phase transformer, is used to provide an artificial and support loads neutral point for the system with no neutral point and the system grounding. Grounding modes: direct grounding, combination grounding with arc suppression coil or resistor or grounding reactor and etc., grounding transformer can be used as a substation power with a secondary winding for continuous use. Grounding transformers produced in our company have the majority of users in recent years with low loss, low noise and reliable performance. Technical parameter: Rated capacity: 23~6500kVA; Rated voltage: 10~66kV/0.24kV.
3. Performance description for THT-DKSC series of dry-type grounding transformer

3.1 Good electrical properties and low values of partial discharge: Dry-type transformer can make the values of the partial discharge lower due to its unique structure (all the high and low voltage winding are wound with copper belt (foil)) and advanced manufacturing technology level (all the high and low voltage winding are poured with epoxy resin in vacuo and cured).

3.2 Strong ability of resistant to lightning impulse: Due to all the high and low voltage windings are wound with copper belt (foil) causing the voltage between layers to be lower and the capacity larger as well as the starting voltage distribution of the foil windings is nearly linear, the anti-lighting impulse ability is strong.

3.3 Strong ability of short circuit withstand: Due to the reactance in the high and low voltage windings is the same with no helix angle leading to the ampere turns between coils to be balanced and the axial force of the high and low voltage windings caused by the short- circuit is almost zero, its ability to withstand short circuit is strong.

3.4 Good performance of anti-cracking: Dry-type transformer adopts epoxy resin "thin and insulation (1-3mm) technology “to satisfy the low and high temperature and occasions with large temperature range, to meet the anti-cracking requirements after long-time running and to resolve the cracking problem which is hard for "thick and insulation (6mm) technology”, so that the dry-type transformer is ensured the reliable protection in technology.

3.5 Overload capability: If the load losses of the transformer with the same capacity are equal, the area of the copper conductor is correspondingly increasing than that of the copper foil, after the volume increased, the amount of filer resin is also increasing, so the hot winding capacity is larger, and the transformer short time overload is stronger.

3.6 Excellent flame retardant property: Adoption of epoxy resin vacuum pouring process has no environmental pollution and is environmentally friendly, such transformers with maintenance-free, moisture proof, damp heat resistance, flame retardant and self-extinction properties apply for a variety of environments and conditions.

3.7 Low loss, low noise: Iron core commonly introduces high-quality cold rolled silicon steel sheet with mineral oxide insulation through advanced processing technology to make the loss level and no-load current to a minimum and achieve very low noise level. Also, the surface of the assembled core shall be coated with Class F resin paint to prevent the dust, corrosion, smoke and rust.

3.8 High temperature resistant: Epoxy resin dry-type transformers are Class F or Class H insulation and can be long-time safe operation under high temperature of 155°Cor 180°C. In the same capacity condition, you can save installation costs for its small size and lightweight.

3.9 Relevant technical specifications: 1.Capacity≤10000kVA; 2.Voltage≤35kV; 3.Insulation class F or H.
 

3.3 System operating conditions

1. System rated voltage

2. System frequency

3. System neutral point grounding mode

4. Range of power grid capacitive current

3.4 Grounding transformer rated capacity options

a) Grounding transformer can be optional according to the needs of the system (the grounding transformer shall be installed when the bus is connecting to the arc suppression coil; shall not be required to install when the transformer or generator neutral point is grounded).
b) The capacity of grounding transformer is equal to 1.1 times that of the arc suppression coil, that the grounding transformer can be with secondary capacity according to the user requirements as the output capacity provided by the user. The resistor matching with the grounding transformer can select the rated capacity of 1/10.
c) If with secondary capacity, the capacity of the grounding transformer is equal to the sum of the arc suppression coil capacity and secondary capacity.

IV. Transport

The storage temperature for the packaged products during transport is -25 °C~+55 °C, relative humidity is no greater than 95%. The product shall withstand short-term storage in this environment.

V. Storage

 Packaged products shall be stored under such conditions: In the indoor environment of -10°C~+40°C storage temperature, with a relative humidity of no greater than 80%, free of corrosive, fire and explosive substances. Special Note: Configuration in the manual is subject to change without notice, and the accompanying instruction shall govern.