Introduction to Switchgears

Introduction to Switchgears. What are Switchgears? Importance of Switchgears Types of Switchgears Applications of Switchgears.

What are Switchgears?. Switchgear refers to the collection of devices used to manage, protect, control and provide safety to electrical circuits and equipment. The primary components of switchgear include: Switches Fuses Circuit breakers Relays.

Importance of Switchgears. Switchgears play a significant role in electrical systems such as providing : Safety - Protects against electrical faults and hazards. Reliability - Ensures continuous and stable electrical supply. Control - Manages electrical flow and operations. Protection - Shields equipment from damage..

Types of Switchgear. MCB MCCB ACB Contactors Overload Relay Domestic Switch Domestic Socket RCCB RCBO Fuse Changeover Switch Connectors Auxiliary Circuit PRCD SFU (Switch Fuse Unit) AFDD ( Arc Fault Detection Device).

Applications of Switchgears. Residential: Ensures safety and efficiency in home electrical systems (e.g., circuit breakers, distribution boards). Commercial: Manages electrical supply and protects equipment in offices and shopping centers. Industrial: Controls and protects complex electrical systems in factories and plants..

Electrical Endurance (EE) Test. What is an Electrical Endurance test? Why Electrical Endurance is important? Arcing Phenomena in Switchgear What are the components of the Electrical Endurance test setup ?.

What is an Electrical Endurance test?. Definition :An electrical endurance test evaluates the durability and reliability of electrical switchgear over an extended period. Concept: Imagine turning a light switch on and off daily. Over time, it wears out. The endurance test simulates this repeated use in a controlled environment to assess how the switchgear performs. Goal : To Determine how many cycles of use the switchgear can handle before malfunctioning or failing..

Importance of Electrical Endurance. Electrical Endurance Test is important because it provides : Consistent Performance: Ensures switchgear works reliably throughout its expected lifespan. Safety: Prevents premature failures, reducing potential hazards. Cost Efficiency: Reduces maintenance costs and unexpected repairs. Compliance: Verifies products meet industry standards for operational efficiency.

Arcing phenomena in switchgear. An electrical arc is a visible discharge of electricity that occurs when a circuit is interrupted under load, generating extremely high temperatures. This phenomenon is observed during the process of separating contacts within switchgear. Whenever the contacts of the Switchgear undergo separation an ⚡“Arc” is generated between the fixed and moving contact because during the making of the switchgear contacts the moving contact strikes on the fixed contact then bounce back before closing onto the fixed contact during this process an arc is generated between the contacts..

What are the components of the Electrical Endurance test setup ?.

Temperature Rise Test. What is a Temperature Rise Test? Purpose of the Temperature Rise Test. Importance of Temperature Rise Test.

What is a Temperature Rise Test?. Definition: Measures the increase in temperature of switchgear parts when subjected to its rated current until the temperature stabilizes. Objective: Ensure the switchgear can handle its rated current without exceeding specified temperature limits by standards..

Purpose of the Temperature Rise Test. Temperature rise test is mainly performed for three main reasons as below: Safety Assurance: Ensures the switchgear doesn’t overheat, preventing insulation failure, fire hazards, or breakdowns. Performance Validation : Make sure that the switchgear maintains integrity and efficiency under normal and fault conditions. Compliance with Standards : Verifies adherence to international standards for maximum permissible temperature rise..

Importance of Temperature Rise Test. The temperature rise test is important for : Quality Assurance Thermal Hazard Prevention Smooth Operational Working.

Dielectric Verification Test. What is Dielectric Test? Purpose of Dielectric test Tests performed in Dielectric Test.

Typical Set up for Dielectric Test. Definition :Dielectric Verification is a test setup that is used to verify the dielectric property of the switchgear. Purpose: Insulation Verification - Tests insulation reliability by applying high voltage across terminals. Safety: Ensure safe operation under normal and extreme conditions..

Purpose of Dielectric Verification Test. Verifying Insulation Strength: Ensure insulation withstands specified voltage without failure. Safety: Ensures that the switchgear handles normal and transient voltage surges safely. Compliance: Meets industry standards for dielectric performance.. Identify Weaknesses: Reveals potential insulation flaws under high-voltage stress..

Tests Performed in Dielectric Test. Dielectric verification test includes two types of test they are as below: 1. Power Frequency Withstand Test: Evaluating insulation strength by applying high voltage AC at power frequency (50 Hz)The power Purpose of this test is to test the ability of insulation to handle voltage without breakdown or failures. In this test the voltage is gradually increased to monitor the signs of failure or any faults that may occur. 2. Impulse Withstand Test : The impulse withstand test evaluates a switchgear's ability to endure sudden high-voltage surges, typically generated by an impulse generator. In this test impulse is applied from a generator to check for breakdown or flashover..

Characteristics Verification (CV) Test. What is CV Test What all test are performed under CV test?.

What is Characteristics Verification Test?. Definition :A set-up which is used to verify the tripping characteristics of the circuit breaker is called characteristics verification test. Purpose: Verify Operation- Ensures that the switchgear functions as expected and withstands all the abnormal conditions. Ensure Safety: Provide strong, reliable and resilient electrical system ensuring safety of the electrical network..

What all test are performed under CV test. Mainly three tests are performed in Characteristics Verification Test, they are : Trip Test: Injects a current greater than the rated current. Non-Trip Test: Injects a slightly higher current than the rated current. Thermal Overload Test:Simulates an overload by applying higher-than-normal current. Ensures the switchgear can handle excess heat without safety issues. Instantaneous Test: Instantaneous test verifies a protective device's functionality by assessing its response to hold and trip currents..

Force and Distance Test. What is Force and Distance Test? Why Force and Distance Test is important?.

What is Force and Distance Test?. A procedure designed to measure : Force Required: Amount of force needed to initiate the tripping of a circuit breaker. Distance Traveled: Distance the lever moves during the tripping process. Ensures circuit breakers trip correctly at the designated force, maintaining safety..

Why Force and Distance Test is important?. Accurate Calibration: Ensures circuit breakers trip at the correct force level. Reliable Performance: Confirms tripping mechanism activates correctly under operating conditions..

millivolt Drop. What is millivolt Drop test? Why millivolt Drop Test is performed ?.

What is millivolt Drop Test ?. The millivolt drop test is a standard procedure used to evaluate the quality of electrical contacts within switchgear. Purpose of this test Is to check contact condition by analyzing the voltage loss in millivolts to ensure low resistance and effective current flow. The millivolt drop test is usually performed using a micro-ohmmeter, a device that measures low voltage direct current (DC) through the contacts and records the resulting voltage drop..

Why millivolt Drop Test is performed?. Efficiency: More practical than temperature rise tests, which are time-consuming. Contact Resistance: Ensures that resistance is within limits for reliable performance. Prevent Overheating: High resistance generates heat that can degrade contacts and pose fire hazards..

Warm Calibration. What is Warm Calibration? Why Warm Calibration is important?.

What is Warm calibration?. Definition: Adjusting the tripping mechanism of switchgear by simulating fault conditions and loading. Process: Expose switchgear to specific loading conditions. Bimetallic component heats up and bends. Bending moves a screw towards a fulcrum point. Activates a lever in the tripping mechanism. This process ensures that switchgear functions accurately to electrical currents.

Why Warm Calibration is important?. Variations in Manufacturing: Even with identical specifications, variations may occur Variations may occur in the distance between the bent bimetal and the tripping lever, so to precisely adjust that distance warm calibration is required. Bimetallic Strip Function: Inside devices like circuit breakers, a bimetallic strip bends when heated. This bending is crucial for the device to function correctly, such as breaking a circuit or switching off. Warm calibration ensures that this bending occurs precisely at the intended temperature or current level, aligning the device’s operation with its characteristic curve. Testing Under Load: Identifies behavior changes of the switchgear due to thermal effects. Safety: For safety critical devices like circuit breakers, accurate warm calibration is essential to ensure they activate at the correct temperature or current threshold.

Cold Calibration. What is Cold Calibration? Importance and Process of Cold Calibration.

What is cold calibration?. Definition: Adjusting switchgear tripping characteristics without connecting to an electrical source or load. Ensures that switchgear's tripping characteristics are aligned with the specifications. Performing cold calibration in a controlled environment without electrical loading, helps achieve the accurate/ close to accurate and consistent performance simulating the conditions that the switchgear would experience during actual operation..

Importance and Process of Cold Calibration. Ensures precise alignment of the bimetallic strip, preventing mechanical errors. Provides proper setting up of the device before Warm Calibration which contributes in reliability and consistent performance throughout device lifecycle. Process: Place the bimetallic strip on fulcrum. Tighten screw until it contacts the fulcrum. Unscrew by 3-5 threads for correct tension. Prepare for warm calibration to verify performance..