Indepth Electrical engineering

Service-Age of Medium Voltage Power Cables: Life, Testing, and Maintenance Introduction Power cables are the lifelines of any electrical system, ensuring reliable energy transfer to equipment and utilities. While many types of cables exist in the market, their performance and life expectancy depend heavily on installation practices, operating conditions, and maintenance. Typically, electrical cables last 20–30 years under optimal conditions. However, environmental factors such as open-air exposure, trenches, conduits, cable trays, load cycles, and frequent start-stop operations can significantly influence cable health. In the United States, the aging MV (medium-voltage) cable infrastructure has become a pressing issue. Many utilities and industries rely on networks that are decades old, raising the question: How do we accurately assess the condition of service-aged power cables? What Is a Service-Age of Cables? A cable is considered service-aged after five years of ...

Bushings in Transmission Systems: Types, Classification & Applications Bushings are one of the most critical components in transmission and distribution systems . Their primary role is to provide insulation between energized conductors and grounded parts , ensuring safe current transfer through transformer tanks, circuit breakers, switchgear, and other high-voltage equipment. A failure in bushings can lead to catastrophic equipment damage, fire hazards, or extended outages. Hence, understanding their classification, design, and application is vital for electrical engineers and maintenance teams. Classification of Bushings Bushings can be classified into three main categories: 1.       Based on Insulating Material Used 2.       Based on Construction Type 3.       Based on Internal Insulation 1. Classification by Insulating Material Bushings are often categorized based on the type...

Electrical vehicles seems to becoming reality as there is increased focus on reducing pollution and reducing dependency on petroleum products. But there are many challenges while going with electric vehicles such as time required for charging the vehicles and space required for parking the vehicles and also higher cost of electric vehicles in comparison to other vehicles. There is also challenge for long driving as while driving long charging of vehicles will be required after few intervals, which required considerable time for charging again. There is lot of infrastructure and electricity is required to cater all these problems. Cost of driving electric vehicle is very low in comparison to petroleum products. There are few terms you must know before going through in details:- On Board Charging:- There are chargers which are factory fitted and are known as on board chargers and there are 2 types of charging devices for the same:- (i)       ...

Three-phase power — single-phase + three-phase loads explained (clean, compact & worked examples) Key rules  Power adds. Whether a load is single-phase or three-phase, its real power (kW) adds algebraically. A statement like “three-phase load = 90 kW” means total three-phase real power = 90 kW (i.e., 30 kW per phase in a balanced system), not 90 kW per phase. For balanced three-phase loads, you can convert total ↔ per-phase by dividing or multiplying by 3: P phase = P total / 3 P_{\text{phase}} = P_{\text{total}}/3 P total = 3 × P phase P_{\text{total}} = 3 \times P_{\text{phase}} Important formulas Total three-phase real power (line-to-line voltage) P 3φ    ( kW ) = 3    V L − L    I    P F 1000 P_{\text{3φ}}\;(\text{kW})=\dfrac{\sqrt{3}\;V_{L-L}\;I\;PF}{1000} where V L − L V_{L-L} is line-to-line RMS voltage, I I is line current (A), and P F PF is power factor. Total three-phase real power (line-to-neutral / per-phase voltage) P 3φ    ( kW...

National Electrical Code (NFPA 70) – Working Spaces for 600 V Electrical Equipment In electrical installations, providing adequate working space around electrical equipment is not just good engineering practice—it is a mandatory safety requirement under the National Electrical Code (NEC/NFPA 70) . These provisions are designed to ensure safe operation, inspection, and maintenance of equipment rated at 600 Volts, nominal, or less . This article explains the key working space requirements , exceptions, and clearances mandated by NEC for low-voltage electrical systems. 1. General Requirement for Working Space Sufficient access and working space must be provided for safe operation, inspection, and maintenance . Spaces must comply with NEC specifications regarding depth, width, and height . No storage or obstruction is allowed in the designated working space. 2. Working Space Depth Requirements (a) Minimum Depth The minimum clear working distance depends on system volt...