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Examoogle • User • info@examoogle.com • EE-2024-8821
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Which is not an advantage of static relay?
Fast speed
Less maintenance
Less burden
Less Price
Less Price
Quick Summary: Static relays use electronic components (transistors, diodes, integrated circuits) instead of moving mechanical parts to perform switching and logic operations. While they offer superior speed and sensitivity, they are generally more expensive than traditional electromagnetic (electromechanical) relays due to the cost of electronic components and the need for auxiliary power supplies.
Static relays use electronic components (transistors, diodes, integrated circuits) instead of moving mechanical parts to perform switching and logic operations. While they offer superior speed and sensitivity, they are generally more expensive than traditional electromagnetic (electromechanical) relays due to the cost of electronic components and the need for auxiliary power supplies.
top=k×f(I) — where top is operating time and f(I) is the relay characteristic curve.
Static relays consist of a measuring unit, a logic circuit, and an output amplifier. The measuring unit compares the input signal (current or voltage) against a reference value. The electronic logic circuitry processes this signal to determine if a fault condition exists, and if so, triggers the output amplifier to initiate the trip command.
Static relays contain no moving parts, resulting in higher resistance to shock and vibration.
They provide high sensitivity and repeatability in fault detection.
They require an auxiliary DC power supply for electronic components to function.
The primary disadvantage is the higher cost relative to electromechanical alternatives.
Fast operating speed
Less maintenance (no contacts to wear out)
Lower burden on instrument transformers
High sensitivity and accuracy
High price compared to electromagnetic relays
Susceptible to transient voltage spikes (surges)
Requires auxiliary DC power source
Complex circuit testing
Distance protection for transmission lines
Differential protection for transformers
High-speed fault clearance in power grids
| Feature | Static Relay | Electromechanical Relay |
|---|---|---|
Cost | Higher | Lower |
Option A, B, and C are established advantages of static relays: high speed (typical 1-2 cycles), minimal maintenance due to absence of mechanical wear, and low burden allowing the use of smaller instrument transformers.
Static relays are sensitive to ambient temperature and electromagnetic interference (EMI).
D is correct — Static relays are generally more expensive than their electromagnetic counterparts due to the cost of semiconductor components and the requirement for external power circuitry.
Always remember that 'Less maintenance' and 'Less burden' are standard benefits of static/digital relays, while 'Higher price' is the trade-off you pay for those technical improvements.