About Voltage Sag

Definition

A voltage sag/dip is an occurrence where the rms value of the line voltage suddenly drops and goes up to normal in a short time. IEEE calls it voltage sag, while IEC names it voltage dip. It typically lasts 10ms‒1min.

Harm

A voltage sag will lead to unexpected shutdown of on-going production equipment, product quality decline or production hold-up. More seriously, it may result in machinery break-down and electrical apparatus burnout, or even safety accidents.

Causes

Load side: In a short time, the power line goes through a current far greater than a normal value. This results in a large voltage loss and a voltage far less than normal. For example, substantial load increase out of blue.

Grid side: In extreme climatic conditions (e.g., strong wind, thunder and lightning), a voltage sag may occur upon power company device failure, construction or traffic accident, or relay protection and switching actions on the grid side.

Voltage Sag Tends to Occur in：

Dynamic Voltage Regulator（DVR）

When the power line undergoes a voltage sag or surge, this may cause a critical security threat in power supplying for an enterprise. More seriously, it may cause significant property loss and personal loss. Use of a DVR alleviates such a threat or even avoids related loss.

A DVR is a cutting-edge power electronic device. It employs both advanced power electronic semiconductor technologies and control technologies to ensure safe use of electricity. To ensure stable power supplying to sensitive devices at the backend, our DVR uses world-leading control chips such as DSP/FPGA/CPLD to monitor line voltage quality. When a voltage sag or surge is detected, our DVR can instantly switch related backend devices to be powered by an inverter. The manipulation and shutdown of our DVR is controlled by software, and its typical switching cycle may be limited to no more than 1ms, making sure that the power supplied to the devices will not be interrupted. You can select supercapacitors or lithium batteries as backup power sources to meet your own requirements. The duration for backup power supplying depends on the capacity of those supercapacitors or batteries.

                                                                                                         DVR

Product Features

• High reliability: Our cabinet applies an integrated design frame, which is highly environmentally adaptable, for it uses less components, and each of them has a powerful anti-shock function and long service life; it also provides a separate air way for cooling, where the air comes in from the bottom and out through the top, effectively preventing dusts from accumulating within the cabinet.

• Short response time: A global response time of less than 1ms ensures constant power supplying.

• Excellent charging capability: Our product supports charging energy storage units to their full capacities. Therefore, after a severe voltage sag occurs for the first time, it can rapidly charge the energy storage units that have been discharged. As a result, a problem that the voltage drops continuously in thunder and lightning weather can be effectively addresses.
• High utilization rate of energy storage units: A wider range of input DC voltages bring more convenience for you to optimize your initial investment.
• Ease of operation and maintenance: Use of supercapacitors contributes to a long service life and simplicity in maintenance; and our power control products employ a modular design.

• Intelligent management of energy storage units: We apply an intelligent system for super capacity management, and therefore, can detect in real time when a supercapacitor is working improperly.

DVR Technical Parameters

Note: For DVR products of other specifications, contact us for further information.