Knowledge

Q: People call TDR "Cable Radar." How does it find a fault without digging? A: TDR sends a low-voltage pulse (<100V) and listens for the

Q: Why is DC Hipot now strictly forbidden by standards like IEEE 400.1 for XLPE cables? A: Because XLPE is a solid polymer. Under high DC electric fie

Q: Testing on a humid, rainy day shows extremely low IR. What is the Guard terminal? A: The Guard (G) terminal acts like a bypass valve to eliminate c

Q: My megger has 500V, 1000V, 2500V, 5000V, and 10kV. Which should I choose for LV, MV, and HV? A: Applying too little voltage won't stress insulation

Q: I am testing an old paper-insulated lead cable (PILC) and a modern XLPE cable. Same IR results? A: No, absolutely not. XLPE and PILC are physically

Q: Modern analyzers weigh only 9 kg and run on 120V, yet they can measure a 4000V knee point. How? A: Basic physics. The secret is the Variable Freque

Q: This is the most famous safety rule. What is the physical reason behind it? A: Swapping their operating states turns their source characteristics i

Q: Why do we care about a few hundred milliohms (mΩ) in the CT winding? A: Because internal resistance is part of the Total Burden. It limits ho

Q: How do I know which CT is for my meter and which is for my relay? A: CTs are specialized. Meters need precision at normal loads; relays need it dur

Q: I see P1/P2 on the primary and S1/S2 on the secondary. What does it actually mean? A: Polarity tells us the relative direction of current. Since AC

What is the "Knee Point" during CT testing? Think of a CT like a towel soaking up water. At first, it absorbs water (voltage) easily. But ev

Q: My 50 kV / 5 kVA test transformer - boss says "just connect it to the 3 km cable." Something feels wrong. Am I right? A: YOU ARE RIGHT. D