PZG Intelligent Fault Passage Indicator
The PZG series distribution line fault locating system does much more than a standard fault passage indicator. It comprises three acquisition units (one per phase), and a pole-mounted collection unit, it is installed on distribution lines to measure current and voltage. It operates as a distribution automation master station during the regular operation of distribution lines and detects overcurrent and earth fault. During normal operation it provides, real-time values of the operating parameters giving the status of the system. In the event of a fault, the system gives a visible, flashing indication of the passage of fault current, whilst collecting data to locate the fault and saves waveforms in Comtrade format for subsequent analysis. It will also monitor and provide measurements of current and voltage.
This data can then be used for automated fast supply restoration, or can be transmitted to a remote master station for appropriate action to be taken. The acquisition units can be powered from a line-mounted VT or from a solar panel.
These are backed-up with a super-capacitor and a lithium ion battery to ensure that the equipment continues to operate under all conditions. The collection unit has two options available; these are either; a capacitor voltage-divider with a supercapacitor as backup; or, a solar panel with a rechargeable lithium battery as back-up.
The PZG series of distribution line fault location device is ideal for 6kV- 35kV distribution networks, including those with unearthed neutral points, arc suppression coil earthing and systems with low resistance earthing.
Low current earth fault detection
In addition to giving data concerning system disturbances, the PZG can identify difficult to detect occurrences, such as low current faults which may be as a result of dangerous situations such as downed conductors.
If such a high resistance earth fault occurs, the current may be insufficient to be recognised as a fault. In this case, the faulty section can be identified from the direction of the transient zero-sequence currents which the collector unit can extract from the currents measured by the line-mounted acquisition units. These will have opposite polarities at either end of the faulty section, and the amplitude and waveform are different. In contrast, the transient zero-sequence currents of the healthy sections have the same polarity and similar amplitudes and waveforms. Hence, the master station can identify the section in which the fault has occurred.
Wireless Acquisition Unit (Line Mounted)
|Rated operating frequency||50/60Hz|
|Rated operating voltage||≤35kV|
|Fault indication||Red LED; flashing period: 5s, lighting time ≤ 50ms; 360° omnidirectional.|
|Visible distance||200m during the day; 500m at night|
|Reset time||Power-on automatic reset time: <5min. Timing reset time: can be set (48h, minimum resolution 1min)|
|Accurate current measurement (Line current)||4 – 600A (Maximum measured current 1200A)|
|Recording length||12 cycles, 80 points / power frequency cycle|
|Cyclic storage||64 groups, following the Comtrade standard|
|Accurate current measurement (Line current)||5 – 600A (Maximum measured current 1200A)|
|Self-powered operation||> 4A load current|
|Super capacitor capacity||Independently maintain full-featured operation when fully charged ≥12h|
|Power consumption||Minimum average operating current ≤ 80uA|
|Overhead line cable diameter||8-32mm (∅)|
|Dimensions||118mm × 176mm × 118mm (width × height × depth)|
|Loading and unloading life||>50 times without damage|
|Mechanical strength (earthquake, drop, vibration)||Vibration level I, tilt drop 1m|
|Ingress protection level||IP67|
|Operating temperature||-40 to +70℃|
Collection Unit (Pole Mounted)
|Rated input voltage||15VDC, ±20%; 20W (solar panel) or alternatively60VAC, ±20% (line power/voltage device)|
|Backup power||7Ah/12V (Lithium battery)|
|Power consumption||<0.2VA (online, with no communication)|
|4G/3G wireless communication||Single-way Serial|
|Serial port||1, EIA/RS232 (1200~19.2kbps)|
|Wireless access to acquisition units||3 groups, 3 units per group|
|Micropower wireless communication||433 – 470MHz，≤10mW（10dBm）|
|Electromagnetic compatibility||IEC standard level IV|
|Dimensions||338mm × 179mm × 102mm (width × height × depth)|