The cable identifier is used to distinguish a specific cable among a bundle of cables during the installation, relocation, maintenance, and fault handling of power cables; it features accurate identification (dual qualitative and quantitative discrimination), speed, precision, simple operation, and wide application range.
It is of great significance in cable construction and maintenance work. The live cable identifier uses microcontroller technology at the transmitting end to encode the transmitted signal, driving a large-aperture clamp to emit a phase-encoded current signal with an average value of zero. The microcontroller in the receiver decodes the received phase-encoded signal and performs phase identification. Based on the uniqueness of the signal phase characteristics on the target cable, the target cable is distinguished from a large bundle of other cables. The live cable identifier can also directly connect the output signal to a de-energized cable, in which case it can identify ground loops with resistance up to 1000 ohms or more. It is a lightweight, compact, and portable instrument suitable for various types of high and low voltage power cables.
Main Features of the Instrument
This instrument consists of a current pulse transmitter, a receiver, transmitting and receiving clamps, and several connecting wires. It features high-power current pulse output; clear on-site received signal characteristics, easy to carry, lightweight and flexible, high sensitivity, effective suppression of on-site power frequency interference, accurate and fast judgment; reliable protection circuit, not afraid of output short circuit; large clamp opening ф150 suitable for power cables of various cross-sections; built-in high-power isolation transformer, ensuring no direct electrical contact between the operator and the mains. However, it is absolutely forbidden to touch the black and red clip wires with hands while the instrument is energized.
Brief Introduction to Working Principle
Since live cables in operation do not allow any damage to grounding wires or other connections, nor is it allowed to directly apply the output signal of the identifier transmitter to the phase wires of high-voltage cables. Live cable identification needs to solve two difficulties: one is how to couple the identification signal to the cable; the other is that the coupled signal is generally small, while the operating cable may have 50Hz unbalanced current, induced 50Hz interference current, and distributed capacitance current, which constitute 50Hz power frequency electromagnetic interference, so the high-sensitivity receiving clamp must address how to resist 50Hz power frequency interference.
The live cable identifier we developed uses microcontroller encoding and decoding technology at both the transmitting and receiving ends, as well as PSK technology widely used in the communication field. The transmitting clamp emits a phase-encoded signal with an average value of zero. The microcontroller in the receiving clamp filters the received signal through hardware and software, then performs phase identification. When the receiving clamp is clamped on the cable according to the current direction, the current meter of the identified cable deflects to the right, accompanied by audible and visual indication. Other cables have current directions opposite to that of the identified cable, and their current meter pointers deflect to the left, without audible and visual indication. This reflects the uniqueness of the target cable to be identified, making it easy to distinguish the identified cable from multiple cables. Moreover, since the signal current intensity on the identified cable is the same along the entire line, the electromagnetic signal intensity received by the receiving clamp along the cable is consistent. In principle, the identified cable is not limited by its length.
Note: The above information and technical parameters are compiled and released by Yangzhou Darui Electric Co., Ltd.
