Main function​

Based on the traditional DTU function, the metering level distribution line loss acquisition function is added, which optimizes the judgment and location function of small current grounding fault, improves the sampling frequency, and makes the waveform of fault recording closer to the real waveform.​
● Line loss acquisition function​
The distribution line loss acquisition module is used to realize the interval electric energy acquisition function, to measure the electric energy data on the line in real time, including the positive and negative active power and the four quadrant reactive power calculation, so as to realize the two-way metering sub function and support the positioning function.​
● Low current grounding fault judgment and location function​
By analyzing and collecting the data of phase current transformer and zero sequence current transformer, the control unit distinguishes these characteristics through a variety of algorithms, so as to accurately locate the fault area.​
● Fault wave recording function​
Through sampling at 128 points per cycle, the waveform of each channel of the first 4 cycles and the 8 cycles after the fault, as well as the location and other remote signaling information are completely recorded, which is sent to the master station to analyze the cause of the fault, and it supports the cyclic storage of 64 fault records.

​
Product functional characteristics​
● It meets the requirements of feeder automation, and the controller takes line voltage as the criterion;
● Through the cooperation of delayed closing and substation protection, the local fault handling can be realized. The complete feeder automation terminal function can be realized without the need of storage battery, communication and master station;
● The possibility that the system may be unstable due to storage battery and other components requiring maintenance has been abandoned in design;
● Clear functions of distribution automation system and easy operation;
● It adopts frequently operated load switch/circuit breaker to meet the economic operation requirements of distribution network automation;
● It adopts SF6 insulated load switch or vacuum circuit breaker to realize SF6 arc extinguishing or insulation;
● Three phase co-box layout, cable casting or pressing outgoing line, fully sealed mechanism, military level aviation interface, and overall fully sealed technical guarantee make the product weather resistant and anti-condensation performance good, and maintenance free for at least 15 years;
● Reliable sealing performance, IP67 protection grade, mature shell sealing technology, one-time molding technology of tooling mould, high mechanical strength, and good air tightness of the box;
● Built in isolating distance and vacuum arc-extinguishing chamber are connected in series asynchronously, with good opening and closing capacity and strong safety;
● It has maintenance free characteristics. The primary circuit, secondary circuit and operating mechanism of the load switch/polo-mounted circuit breaker are sealed in SF6 gas and are not affected by the external environment. Its performance is stable, reliable and maintenance free.

Solution No.		01		02		03		04
Busbar specification：630A
Primary rated voltage: 12kV​
Secondary rated voltage: DC48V
Primary solution wiring diagram of ring main unit​
Switch cabinet No​				AH1		AH2		AH3
Purpose of switch cabinet​		DTU cabinet		Bus PT unit​		Load switch unit​		Circuit breaker unit​
Electrical main equipment components​	Load switch (three positions)​			FLN □ 12/630A	1 set	FLN □ 12/630A	1 set
	Circuit breaker							ZN □ 12/630A	1set
	Isolating/grounding switch​			20kA	1 set	20kA	1 set	20kA	1set
	Operating mechanism​			Manual​	1 set	Manual/electric DC48V​	1 set	Manual/electric DC48V	1 group
	Voltage transformer​				1 set
	Current transformer​
	Zero sequence current transformer​			10/√3  0.1/√3   0.22/√3  0.1/3kV 30/300/30VA		600/1 0.5S(5P10)5VA	3 pcs	600/1 0.5S(5P10)5VA	3pcs
	Fuse​			XRNP-0.5A/50kA	3 pcs
	Voltage indicator​			DXN8D-12/T45	1 pcs	DXN8D-12/T4S	1 pcs	DXN8D-12/T4S	1pcs
	Distribution automation terminal​	75C68J	1 set
	Ammeter​					600/1	3 pcs	600/1	3 pcs
	Voltmeter​			99T1-A 10/0.1kV	3 pcs