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Breakdown Voltage (BDV) of Transformer Oil Breakdown Voltage (BDV) indicates the voltage above which an oil electrically breaks down. According to IS 335, new unfiltered transformer oil should have a breakdown voltage above 30 kV (rms) when tested with a 2.5 mm gap. For filtered new transformer oil, it is greater than 60 kV (rms) … 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
Current Transformers are essential for protection and measurement. To work correctly, they must reproduce primary current in a fixed ratio on the secondary side. However, CTs are not ideal. They suffer from three major types of errors. Ratio Error (Magnitude Error) in CTs The CT can not produce the exact scaled-down current. The actual secondary … Read more
A watt-hour meter-type induction relay is essentially a variant of an electromagnetic induction relay. Instead of only current or only voltage, it operates based on the relay’s power input. Obviously, these relays require both the system’s voltage and current to operate. Power is the product of voltage, current, and power factor \(cos \theta\). Here, the … Read more
A static electrical relay is a protection relay. It uses solid-state electronic circuits. Additionally, it does not contain any electromagnetic coils or moving parts. Therefore, we refer to it as a static relay. Basic Structure of an Electrical Static Relay A static relay operates using electronic components and circuits. For example, these components include diodes, … Read more
The High Impedance Bus Differential Protection is a very interesting subject to study. A busbar is a critical component in a power substation. It ensures the proper connection of all incoming and outgoing feeders to a single voltage level system. Obviously, if a fault occurs on the bus itself and does not promptly clear, it may cause permanent damage to the … Read more
A Numerical Protection Relay: Modern Power System Protection A numerical protection relay is a breakthrough in power system protection technology. Unlike electromagnetic relays and static relays, this relay uses microprocessor-based technology. It combines digital signal processing, advanced algorithms, and communication systems. Today, numerical protection relays form the backbone of modern power system protection schemes. What … Read more
For Battery Sizing Calculation First, we consider a single battery bank for DC power for the entire substation. In our case, the DC system is 220V; hence, we first set the voltage rating of our battery to 220V. Here, we need to note for future extension of the substation. Because once we installed the battery … Read more
A voltage transformer is a type of instrument transformer. We also call it a potential transformer. It reduces high voltage to a lower and measurable value according to its turns ratio. We need to measure the voltage in extra-high-voltage (EHV) systems. However, a normal measuring instrument cannot measure such high voltages directly. So, a voltage … Read more
A High Voltage Circuit Breaker (HVCB) is a crucial component in power transmission and distribution networks. Its primary role is to protect electrical equipment by interrupting fault currents within the system. Beyond safeguarding equipment, HVCBs are vital for maintaining the integrity of the power grid. They isolate faults effectively, ensuring that adjacent systems remain unaffected … Read more