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Surya Before entering the topic of line differential protection, or simply differential protection of a transmission line, we shall first recall our concept of differential protection. Actually, the differential protection used for a transmission line is called line differential protection. We have already heard about the differential protection of transformers, busbars, etc. The same principle is … Read more
Type Tests on a Lightning Arrester as per IS 3070 Routine Tests on a Lightning Arrester as per IS 3070 Routine Tests on a Surge Monitor Acceptance Tests on a Lightning Arrester Acceptance Test on a Surge Monitor
Type Tests on Capacitor Bank Routine Tests on Capacitor Bank Acceptance Tests on Capacitor Bank The type tests and routine tests are repeated on samples as factory acceptance tests.
Type Tests of Capacitive Voltage Transformer (CVT) These tests are done according to IS: 3156 (Part-1) Routine Tests These tests are done according to IS: 3156 (Part-1)
Type Tests for XLPE Copper Cable Tests on Conductor Tests on Insulation Tests on Semiconductor Layer on the Insulation Tests on Metallic Screen Tests on Metallic Sheath Tests on Armours Tests on Outer Sheath Tests on Complete Cable Specimen Routine Tests on XLPE HV Cables Acceptance Tests on XLPE HV Cables
As the name suggests, ferroresonance is a resonance phenomenon related to iron. Ferro means ‘iron’. Before understanding the ferroresonance, let us recall the concept of resonance first. Suppose, we have a series RLC circuit, across which a voltage source is connected. Say a current I flowing through the circuit. VL is the voltage developed across … Read more
An Oil Surge Relay, or OSR, is a type of mechanical relay. It operates in response to a sudden oil surge. Need for Separate Diverter Tank Every modern power transformer includes an On-Load Tap Changer (OLTC). During tap-changing operations, some arcing always occurs at the diverter switch contacts. It is desirable to change tap positions … Read more
The Earth Continuity Conductor or ECC provides an alternate fault current path in EHV installations, limiting dangerous sheath voltage and safeguarding cable insulation. Sometimes, we also call it Earth Continuity Cable. We most commonly use single-core cables for underground high-voltage transmission systems. This is because 3-core high-voltage transmission cables, mainly above 33kV, are not easily … Read more
The Nitrogen Injection Fire Protection System (NIFPS) prevents and extinguishes fires in oil-filled transformers. Thereby, it safeguards critical power infrastructure. We also commonly call it the Nitrogen Injection Fire Prevention & Extinguishing System (NIFPES). This system operates on a “drain and stir” principle, effectively mitigating fire hazards through a coordinated sequence of actions. Working Principle … Read more
Type Tests for above 33KV up to 220KV XLPE Copper Cable Tests on Conductor Tests on Insulation 3. Measurement of Thickness of Insulation4. Measurement of tensile strength and elongation at break5. Thermal ageing in air oven6. Hot set test7. Shrinkage test8. Void and contaminants test Tests on semiconductive layers of the insulation 9. Resistivity test … Read more
A power transformer has high cost, large size, and complex design. So, identifying defects at the final stage of manufacturing can lead to significant delays, expenses, and operational challenges. Therefore, standards always recommend performing different tests and inspections during various stages of manufacturing. That means the standards always prefer to perform stage inspections of a … Read more
Some the important parameters are listed here for the reference only. The actual technical parameters of a potential transformer may be somewhat different depending on the actual requirements.
What is the Rated Voltage Factor in voltage transformers, and how is it determined? This is the ratio of the maximum operating voltage to the rated primary voltage of the PT. We have to multiply this factor by the primary rated voltage. This determines the maximum operating voltage of the PT. In other words, this … Read more
What is the definition of the rated voltage of a lightning arrester? As per IS 3070, the definition of the “rated voltage of a Lightning Arrester” is given below.The maximum permissible r.m.s. value of power-frequency voltage between the line and earth terminal under temporary over-voltage conditions for a duration of 10 seconds as established in … Read more
Type Tests for the transformer Routine Tests on the Transformer Stage Inspection Tests On Core: On Coil On Tank Acceptance Tests
The clearance requirements for HV and LV terminals in the air are as follows:For 66 kV side, the phase-to-phase and phase-to-earth clearance should be 700 mm, and 660 mm respectively.For 12 kV side, the phase-to-phase and phase-to-earth clearance should be 280 mm, and 140 mm respectively. The following points should be noted for designing winding … Read more
A Digital Teleprotection Coupler (DTPC) is often referred as a Digital Protection Coupler (DPC). It serves as a high-speed, reliable interface for transmitting protection commands between substations over a communication medium (OPGW). Typically it is used for carrier protection of transmission lines. Working Principle First, a protective relay such as a digital distance relay or … Read more
We also refer to a Gas Insulated Switchgear (GIS) as a Gas Insulated Substation. Why is GIS the Future of High-Voltage Power Systems? There are several reasons for preferring a Gas-Insulated System (GIS) over an Air Insulated System (AIS). Constructional Details of Gas Insulated Substation (GIS) A GIS consists of several key modules, each performing … Read more
Type Tests of SF6 Circuit Breakers as per IS-13118: Routine Tests on SF6 Circuit Breaker as per IS-12729. Acceptance Tests on SF6 Circuit Breaker
A miniature circuit breaker, or MCB, is an essential protective device in low-voltage electrical systems because it protects the circuit from both overload and short-circuit faults. Let us explore the constructional details and the working of an MCB. Introduction to MCB An MCB has two main functions. We can use it as a toggle switch … Read more