DC contractor in Wind Turbine System


As the requirement of electrical energy has been increasing, you are already familiar, renewable energy resources are the important means of electricity and energy conversions. There are different types of renewable energy resources, such as solar pv, hydroelectricity, biomass and wind energy. In this article wind energy importance and the function of contactors in wind turbines has been discussed. You will find various types of DC contactors on our website for multiple purposes. One category of DC contactors serves the energy resources sector. These are used in wind power systems as a DC power control.
Approximately, 22% of all the world’s power supply comes from renewable energy resources and this portion is increasing day by day, as the fossil fuel reserves are depleting vastly. Wind energy has been originated to be a vast power reserve ever since the time when human culture has developed. From that era, wind energy, along with solar energy, is readily available everywhere, its demand is increasing, and many companies are investing in wind power stations. It is proved to be adventitious in terms of generation and expense. Wind speed and power forecasting systems are vital for various reasons such as, for maintenance arrangement.
In these changing times, it is important for any successful company to keep up with the latest trends in power demands and its various components. DC contactors is one of such components of wind energy mechanism, let us see the part of contactors in wind turbines.

Role of DC contactor in Wind Turbine System:

Wind energy is expected to have emerging role in renewable energy resources with over 250,000W produced globally. Wind turbines are mature and reliable technology available in multiple size ranging from hundreds of watts to multi giant megawatts. To achieve greater energy efficiency, it is important to increase the system’s operating voltage.
DC contactors are ideal for wind energy application to ensure the connection is maintained under strict conditions. The use of these DC contactors provides utmost safe operation, total insensitivity to voltage loss, energy saving and elimination of risk of coil burning.
DC contactor is an electrically controlled switch used for switching electric power circuit, like a relay except with higher current rating. DC contactors are available in many forms with varying capacities and features. Unlike a circuit breaker, a contractor is not intended to interrupt a short circuit current. DC contactors range from those having a breaking current of several amperes to thousands of amperes and 24 V DC to many kilovolts. The physical size of DC contactors ranges from a device small enough to pick up with one hand, to large devices approximately a meter on a side.
As in induction motors, various designs have been made in wind turbines including the famous double rating engine, but these designs are used for engines of less than 1 MW. Above 600 KW, rated voltage is mostly 690 V. As induction engine is used directly on grid, at least one DC contactor is needed to ensure constant connection and disconnection.

Mechanism of DC Contactors in Wind Turbines

There are many different DC contactors in wind turbine mechanism. These includes: Single pole DC contactor, 2- pole DC contactor and 3-pole DC contactor. Single pole DC contactors are low power consumption DC contactors designed to control motors and other loads. These DC contactors are designed to work as a main DC contactors or auxiliary DC contactors in all kinds of material handling. Next is 2- pole DC contactors are used for single phase applications. The general-purpose DC contactor line is designed with industrial duty and reliability in mind. Lastly, 3-pole DC contactors are electrically controlled switches (relays) used for switching an electrical power circuit. A DC contactor is typically controlled by a circuit which has a much lower power level than the switched circuit, such as a 24-volt coil electromagnet controlling a 220-volt motor switch.
All these DC contactors are designed to meet different load switching requirements, on both DC and AC end of wind turbines. they are equipped with heat sinks, double winding coils and a stronger spring for higher contact force that makes them very efficient and reliable. One of the special features for 3-pole DC contactor is that it can carry loads up to 600A and 3000V with newly developed switching chambers.  

Failure Modes of DC contactors in Wind Turbine System

There are few instances of failure that can occur while using the DC contactors and as your supplier it is our duty to inform you of these failures. One failure mode is the fusion welding of the main contacts. The cause of fusion welding could be a problem in the pre-charge circuit, or the capacitor may not be charged to the fixed value. If this is the case with your DC contactor, you can either choose the DC contactor with proper pre-charged circuit strategy or the DC contactor with a stronger resistance to the capacitive load.
Another main failure mode of the DC contactor is end gap burnout. The reason for the burnout is the improper connection of the DC contactor from the outer side, which causes unusually high heating. It is important for you to follow the proper assembly requirements of the torque for specific type of DC contactors.

What should you choose?

At HOSTON, we have been ensuring the top quality of our DC contactors for 10 years. The EVQ and EVH series both are extremely reliable and efficient that support wide range of current and voltages.
Epoxy sealed DC contactors (EVQ) supports 12VDC to 900VDC with up to 600 amps continuous currents. Ceramic sealed ceramic DC contactors (EVH) supports 12VDC to 1500VDC with current ranging from 40amps to 400amps. EVH has ceramic sealed technology which enables quick arc-extinguish, and capable of withstanding heat and vibration in harsh environment with no oxidation.
All HOSTONs products are small, compact and light weight, and hermetically sealed with inert gases to ensure no oxidation and this, in turn, approves the total safety of our products. All DC contactors have high safety and reliability, optional with polarized and non-polarized contact. We ensure that all our products are fully tested, approved and certified by international standards. Since the requirements of products changes regularly, we make sure that our products are flexible and adaptable to modern changes. All of this ensures that our costumer have best experience with our product.