Primary Harmonic Suppression

In my country's 6-35KV ungrounded neutral power grid, electromagnetic voltage transformers (PTs) face two related problems:

(1) Overvoltages generated by PT ferroresonance often cause internal insulation breakdown and external insulation discharge, frequently resulting in large-scale power outages due to untimely accident handling or accident escalation.

(2) Arc grounding in the power grid frequently burns out PTs.

The SMR-LXQ primary resonance elimination device can effectively solve the above problems in the following four aspects:

①Eliminating or damping PT ferroresonance overvoltages;

②Effectively suppressing overcurrent flowing through the PT winding during intermittent arc grounding, preventing PT burnout;

③Limiting inrush current generated in the PT primary winding circuit when a single-phase grounding occurs, preventing PT fuse blowout;

④Providing long-term protection against PT damage after a single-phase grounding occurs.

Our company's SMR-LXQ primary resonance elimination device features a significantly improved structural design, starting from increasing the heat capacity of the harmonic suppressor. The harmonic suppressor uses SiC with excellent electrical properties and ultra-fine particles as the base material. It is pressed into a high-density, disc-shaped blank using a large-tonnage press and then sintered at temperatures exceeding 1000 degrees Celsius in a reducing atmosphere. The exposed resistor surface undergoes special treatment to withstand sun and rain, making it suitable for direct indoor and outdoor use. It is small in size, lightweight, dissipates heat quickly, has high strength, and is easy to install.

1. Complete Elimination of Ferromagnetic Resonance

It can quickly and effectively suppress and eliminate frequency-division, power frequency, and high-frequency ferromagnetic resonances caused by the nonlinear excitation characteristics of the PT, fundamentally preventing the damage of resonant overvoltages to equipment.

2. Effective Limitation of Intermittent Arc Grounding Overvoltage

When a single-phase arc grounding occurs in the system, the device can effectively limit the current flowing through the PT neutral point, suppress the amplitude of the arc grounding overvoltage, and prevent the fault from escalating.

3. Comprehensive Suppression of Bus Transient Overvoltage

For instantaneous high-energy impacts caused by system operation or lightning strikes, the device can effectively absorb and suppress them, protecting the PT primary winding insulation from damage.

4. Core Equipment Protection

Protection of Voltage Transformers (PTs): Prevents PT high-voltage fuse blown or even PT burnout due to excessive resonant current.

Protection of Other System Equipment: Maintains grid voltage stability and indirectly protects transformers, circuit breakers, and other high-voltage equipment.

1.This product is essentially a nonlinear resistor; its resistance value changes with the applied voltage.

2.Under normal operating conditions: The device exhibits high resistance (up to several hundred kiloohms), having almost no impact on the system; the PT can still accurately measure phase and line voltages.

3.When ferroresonance or arcing occurs: A relatively high voltage is generated at the PT neutral point. At this time, the damping device senses this voltage, and its resistance rapidly decreases, exhibiting a low-resistance state.

4.Powerful damping: This low resistance provides an efficient discharge path for resonant energy, strongly damping oscillations and absorbing resonant energy, thereby quickly limiting overvoltage to a safe range, preventing the resonance from being sustained and causing it to disappear within a short time.

Baoding Simaier Electric Co., Ltd.was established on July 1, 2009 and is located in the National High-tech Industrial Development Zone of Baoding City, Hebei Province. It is a high-tech enterprise focusing on the research and development of power system automation, relay protection and instrumentation.