Distribution network NKFZW28 watchdog post boundary load switch

A new generation of network watchdog column demarcation load switch NKFZW28

The same with the circuit breaker performance of NKFZW28-12/T630-20kA (4S) copper import and line type more cost-effective

Distribution network watchdog boundary load switch in 10 kV feeder aerial application can greatly reduce the trouble-free lines on the road of collateral forced outage, narrowing the scope of failure blackout, shorten the blackout time users, so as to improve the power supply reliability of the user.

Keywords: watchdog dividing line switch; Power distribution; The line; application

 

Along with the rapid development of power grid, the safety reliability of power supply demand is higher and higher, in view of the weak links in operation of the grid electricity production department to take effective control measures, doing everything possible to reduce one thousand forced outage, narrowing the scope of power. 10 kV feeder overhead line, due to the open-air set up, its safe operation directly affected by the surrounding environment and climate conditions, high accident rate, accident find difficulties, poor safety and reliability problems. Some overhead line longer remote mountainous areas of users, is often affected by the bad weather can't normal use electricity. Boundary load switch to load switch and microcomputer protection measurement and control, and communications module integrated device, with the stem erect, small volume, less investment, the application of it to improve the safety and reliability of the overhead line, is of great significance to ensure the safe operation of power grid.

 

1. 10 kV feeder features of overhead line

 

For far and near suburb power supply company, cooperate the webmaster system of 10 kV feeder for the safety of the power supply is very important. However, 10 kV feeder circuit is characterized by structural diversity, accidents, especially in the ChengJin suburbs and outer suburbs areas there are a lot of overhead transmission lines, the overhead transmission lines are often more branch line, the safety and reliability is poor, meet the wind rain and bad weather, frequent ground and short circuit fault, seriously affected the grid safe and reliable power supply.

 

1.1 line structure complex accident find difficult

 

Users in line with only one or two side, some lines are T meet multiple feeder or more transformer radiated; Some short circuit to dozens of meters, some lines dozens of kilometers long; Some overhead line in the mountains maintenance difficulties, some distribution transformer aging serious; Some broad overhead, have a plenty of hybrid cable overhead line; Some temporary with overhead line cable users, with a temporary change. Overhead line in case of troubleshooting is difficult, especially when the single-phase grounding line, due to the fault point is difficult to determine, often delay the processing of the accident, caused by failure to expand, and further development for short circuit, or damage to the electrical equipment.

 

1.2 line protection configuration is relatively simple

 

10 kV overhead line transformer substation protection configuration flow only commonly, quick break, reclosing protection, in the small resistance grounding system configuration two period of zero sequence protection. Therefore, in order to guarantee the selectivity and sensitivity of relay protection, we must make the whole route in the protection scope, require a failure in the end of the line, protect be sensitive enough. This will across the board due to a malfunction, power outage, and circuit protection are higher and lower JieTiXing cooperate with each other, in the end of the line has no protection, differential time can only lose selective fault tripping and led off the brake.

 

1.3 different 10 kV grounding method

 

For arc suppression coil grounded system, 10 kV distribution line when the single-phase grounding fault line tripping, only send ground signal. For the small resistance grounding system, 10 kV power distribution line configuration zero sequence protection, when single-phase earth fault tripping.

 

1.4 overhead line 10 kV feeder high failure rate, poor reliability, 10 kV feeder high failure rate, poor reliability.

As the user requirements for safety reliability of power supply is more and more high, equipped with microcomputer protection measurement and control, and communications module integrated switch boundary between users and become one of the effective method to solve the problem of the distribution network.

 

 

2. Divide the performance of the load switch and the main role

 

2.1 performance and structure

 

General boundary load switch by switching ontology and see most of the measurement and control unit, the structure diagram 1

 

 

Figure 1 boundary load switch controller

 

 

I load switch between a company's main functions: in the operation of the automatic isolation user side interphase short circuit fault, automatic removal of the user side grounding fault, and can be used to close the load current operation.

 

With a set of boundary load switch external voltage transformer, a set of built-in current transformer; The CPU internal processor and communication module; With voltage during fault tripping judgment and fault memory; Have trip latch function.

 

Boundary load switch is applicable to 10 kV neutral point grounding, approved by arc suppression coil grounding or the low resistance grounding system of 10 kV overhead distribution lines with users (including temporary users) boundary.

 

2.2 the main function

 

2.2.1 automatic removal of single-phase grounding fault

 

When the user side of single-phase grounding fault occurs, dividing line switch automatic brake, dump the fault feeder, ensure substation and feeder on other branches of the safe operation of the user.

 

2.2.2 short-circuit fault isolation and automatically

 

When the user side interphase short circuit fault occurs, boundary load switch in substation for protection tripping, break-brake dump fault line immediately. Substation outlet switch after reclosing, fault line isolation, make the other branches on the feeder users quickly restore power.

 

2.2.3 quickly locate fault point

 

User feeder switch, the boundary between failure only user power responsibility, and can take the initiative to report the fault information, make the electric power company can quickly clear the accident point, timely on-site processing, make the fault line as soon as possible to restore power.

 

2.2.4 monitor user load

 

Boundary load switch testing data can be transmitted power management center, achieve real-time monitoring of distant load.

 

2.3 boundary load switch fault handling

 

Boundary load switch fault handling methods are shown in table 2.

 

 

Table 2 boundary load switch fault handling
Three boundary load switch fixed value and substation protection setting for coordination with the problem

 

3.1 for the neutral point grounding or via arc suppression coil grounded system

 

Interphase short circuit current action constant value: should be considered reliable feeder through the maximum load current. Action time limit should be made to match the substation for the action time of the reclosing protection, before reclosing action, boundary load switch tripping. Due to the Beijing area 10 kV feeder protection reclosing whole as 1 s commonly, can choose 0.3 ~ 0.5 s.

 

Single-phase grounding current action constant value: the zero sequence current fixed value, according to overhead line cross section and length, escape routes should be considered for capacitive current. Due to the neutral point grounding or via arc suppression coil grounding system, the single-phase grounding fault happens, transformer substation line protection tripping, signal grounding, only allowed to run short indirectly. In order to judge fault, and the boundary between the action of load switch time, should consider to avoid the instant grounding deadline, and action again after substation grounding signal trip, can choose 6 ~ 8 s.

 

3.2 for the neutral point via small resistance grounding system

 

Interphase short circuit current action constant value: same as above.

 

Single-phase grounding current action constant value: neutral point via small resistance grounding system, due to the transformer substation of 10 kV overhead line general configuration, two pieces of zero sequence protection for a period of 120 a, time limit of 0.2 s; Two 20 a, time limit for 1 s. Therefore, while dividing line zero sequence current of load switch fixed value and action time, should be made to match the substation zero sequence protection, 0 s.

 

In 4 load switch between running and maintenance problems should be paid attention to

 

Appearance should be regularly check the load switch between ontology and controller are in good condition; Boundary load switch state indicating whether it is right, whether running state energy storage; Porcelain crack, damage; Boundary load switch lead spacing is in accordance with the code requirements; Each part connection fastening, do you have any overheating phenomenon; Lightning arrester is in good condition; Grounding device in good condition, do you have any rust; Controller lights flashing warning.

 

Check whether dividing line load switch rotation or grounding resistance measuring whether extended, load switch between users in internal equipment installed and trouble-free, after the success of the substation feeder circuit breaker tripping overlap, should be timely organization find line fault points, break-brake found boundary load switch, it shall promptly report to the administrative departments of electric (dividing line switch, the controller failure indicator continue flashing 48 h).

 

Should be arranged regularly check for clearing dividing line load switch, inspection period and circuit board rod inspection cycle is the same. Operating more than 10 years in principle boundary load switch should schedule rotation maintenance.

 

5 installation boundary load switch problems should be paid attention to

 

Boundary load switch device can only be installed on the branch line or the end of the line, shall not be used string, as shown in figure 2.

 

 

Figure 2 boundary load switch installation schematic diagram

Boundary load switch as the boundary between power companies and users first circuit breaker, the general installation in 10 kV overhead distribution lines feeder first tree stem, lateral load by the user.

 

When users into line for overhead line, separating the load side of the load switch to suspension insulator suspension overhead insulated wire is introduced into, the user first fundamental pole power supply side insulated wire installed earth wire hanging ring, keep unipolar isolating switch.

 

When users into line for cable line, from the boundary between the load side of the load switch to suspension insulator suspension overhead insulated wire leads to the user the first fundamental pole, the connecting cable directly. Users in the first part pole ring side insulated wire installed hanging earthing wire of power, no longer drop fuse installation, retain unipolar isolating switch.

 

Installed boundary load switch ontology, relevant departments should organize before insulation resistance testing, and power frequency withstand voltage test and test; Insulation resistance measurement standards: use 2500 V wave measuring insulation resistance by megger, boundary load switch, relatively and fracture Ω 1000 M or higher. Power frequency withstand voltage test standard: boundary load switch, relatively and fracture: 42 kV 1 min (such as the boundary between internal load switch installed TV, and do not do withstand voltage test). Boundary load switch points and the closing operation face surface should be toward the outside.

 

Boundary load switch controller installation: controller of installation height should not be less than 2.5 m, the switch control cables (with attachments) controller controller end plug into the controller panel jack, the other end insert boundary load switch base dedicated socket, plug should be tighten. Control cable rope body end, bend and straight segment every 1 m should use 2.5 was fixed, single strands of copper core insulation wire twist plait five laps. Cable should be horizontal flat vertical, should not be skew.

 

6 the conclusion

 

Load switch between applications in the 10 kV overhead lines on the road, greatly reduces the trouble-free line joint forced outage, narrowing the scope of failure blackout, shorten the blackout time users, so as to improve the user power supply reliability.

 

Boundary load switch is better solved the interphase short circuit occurred 10 kV substation, and quickly locate fault point when single-phase earth fault.

 

Distribution network overhead line guard dog boundary load switch
NKFZW28 (VSP5 / FFK) - 12 outdoor vacuum load switch ontology on the pillars

A, product structure and features:

1. Open circuit performance excellence: in the introduction of Toshiba technology, catch up with Japanese technology, expansion design, will close short circuit current capacity to 20 ka; Using vacuum arcing, SF6 gas insulated, switch is in tandem with vacuum arcing chamber isolated fracture, arcing and compression performance is superior. Between them by institutional guarantee action sequence (vacuum arcing chamber disconnected before they close, isolation knife after first disconnect). Is suitable for the breaking load current, the switch in addition to vacuum fracture, inside still have a SF6 isolation fracture string, voltage resistance is superior in particular.

2. High security: arcing and dielectric are oil free medium, explosion-proof devices are installed on the top of the box body, even if the accident internal fault, there will be no high temperature gas leak or splash.

3. Maintenance: the switch main circuit and the operating mechanism of army seal in SF6 gas as the medium of the casing; Switch main circuit USES the cable head to elicit or use our company has patented the corner of the casing.

Table 4. As a result of zero voltage SF6 gas insulated, the switch is exquisite compact volume, at the same time, as far as possible to avoid the leakage hidden trouble. With manual/automatic operation, make the switch operation is flexible. Stay with electromagnetic operating mechanism and electricity. Electricity close to lose electric brake, simple structure and reliable.

5. Installation flexibility: can use hoisting installation method or sit on the pillars.

6. Has the power distribution automation interface: suitable for all kinds of change than current transformer, used to measure and protection and metering, and equipped with remote auxiliary contacts.

7. High reliability: the collection of Japanese Toshiba vacuum crystallization equipment technology and practice for thirty years, with perfect quality management system to ensure that my company, make the production of highly reliability, SF6 gas zero inflation pressure gauge pressure, is not easy to produce leaks, reliable sealing technology, make the gas inside the switch can guarantee the normal work of the 20 years. Achieve no oil, no fire, no explosion danger, the operation is very safe.

8. Don't need to check and maintenance: live part and operating mechanism in a sealed container, is not affected by external environment. Arc is enclosed in a sealed vacuum arcing indoor, there is no pollution source switch inside, so no need for maintenance and repair during the switch operation.

Second, the main technical parameters

rated voltage 额定电压		kV	12
rated current 额定电流		A	630
rated frequency额定频率		Hz	50
Rated short-time resistance current 额定短时耐受电流		Ka(有效值)rms	20（4s）
Close the current rating   额定关合电流		Ka(有效值)Peak	50（4s）
Power frequency withstand voltage   工频耐受电压	Over the earth   对地	Ka(有效值)rms	50
	phase相间		50
	fracture   断口		50
Impulse withstand voltage   冲击耐受电压	Over the earth 对地	Ka(有效值)Peak	75
	phase相间		75
	fracture 断口		85
Rated power flow electrical life 额定电流下电寿命		次	5000
rated mechanical life                        额定机械寿命		次	10000
The rated mechanical life allow ambient temperature 额定机械寿命允许环境温度		℃	-25~+40
weight重量		Kg	185
Conform to the standard 符合标准			IEC256-1 ANSIC37.63 GB3804-90
breaking transformer current 开断感性电流		A	31.5
circuit of capacitive current 开断容性电流		A	10
switch net weight 210kg                开关本体重量210kg			controller net weight 12kg              控制器重量12kg

Zero sequence current transformer

In load this configuration 1 zero sequence current transformer, variable than 20/1, 0.1 ~ 5 a section in the zero sequence current, has a good linear relationship, (0.1 VA) strain ratio under rated load error less than 3%, when the zero sequence current is 400 a, the secondary output current is not less than 5 a.

Operating power supply

Need operation power load switch work. Irfpa operating current can be ac or dc 220 v power supply, but is in commonly 10 kv line on the external power supply transformer or voltage transformer operation, in order to obtain ac 220 v power supply operation, 1 kva capacity, weight 45 kg.

 

  

 

 

JDZW - 10 r outdoor epoxy pouring silicone rubber compound insulation voltage transformer

J -- -- -- -- -- -- -- -- -- -- -- -- -- - voltage transformer

D -- -- -- -- -- -- -- -- -- -- -- -- single phase

Z -- -- -- -- -- -- -- -- -- -- - epoxy pouring

W -- -- -- -- -- -- -- -- outdoor installation

10 - rated voltage (kV)

R - with high voltage side of the fuse

  

Creepage distance is 580 mm

When the customer ordering specific matters

1, the product model, name, parameters, rated voltage, current, short circuit current and communication;

2, transformer ratio and measuring accuracy grade, protection grade CT technical requirements;

3, number and date of delivery;

4, the names and number of spare parts, spare parts;

5, and other special operation requirements, such as contact, accessories, etc.

6, product certification (including PT, CT, zero sequence current transformer)

7, installation instruction manual;

8, packing list;

9, products, secondary wiring diagram. 10 please indicate the sea dials high, if the sea dials high products

 

Delivery date供货日期	site地点
The name of the project工程名称	Project number工程编号
The product name产品名称	Watchdog dividing line circuit load  switch看门狗分界负荷开关
Product model产品型号	NKFZW28F-12
Rated voltage额定电压	10KV
Rated current额定电流	630A
Rated short-time resistance current 额定短时耐受电流	20 KA 4S
Close short circuit current (4 s)             关合短路电流(4S)	50KA
Operator 操作机构	spring弹簧
Controller operating power                  控制器操作电源	AC220V by one outdoor PT(10kV/220V)提供
Shell current transformer phase than壳内电流互感器变比**	A C CT400:5 (10P10)   Zero N CT20:1
Circuit breaker shell Iron断路器外壳	clad coating 铁壳喷塑
(PT and switch)  cable length             PT与开关(2.5平方)电缆长度	10m  (10米)
Switch to the controller cable length开关与控制器(1.5平方)电缆长	10m  (10米)
Either altitude height 海拨高度

 

 

 

 

 

Controller dimension figure controller built-in installation, 12 kg weight, need a hoop fixed outside (fixed hardware)

 

Control cable length of seven meters, air connection plug connection