sectionalizer catalog for greece & mea...

No. SSIEC-GSD-00501

Sectionalizer SPGAS Series 15kV, 27kV, 38kV 400A, 630A

SHINSUNG

Doc. No. SPGASS_GKSP-110922V02

1 Enhanced Self Healing System

Sectionalizer 15kV 27kV, 38kV

1. GENERAL INSTRUCTION

HAZARDOUS VOLTAGE CAN SHOCK, BURN, OR CAUSE DEATH

Do not attempt to handle, install, use or service this product before reading this instruction manual

1.1. SAFETY NOTICES AND WARNINGS The SPGAS LOAD BREAK SWITCH should be installed within the design limitations as described on its nameplate and in these instructions. Also follow your company’s safety procedures. For the safety of personnel performing maintenance operations on the Sectionalizer or connecting equipment, all components should be electrically disconnected by means of a visible break and securely grounded. This product is intended to be operated and maintained by qualified persons thoroughly trained and knowledgeable of the hazards involved. This publication is written only for such qualified persons and is not intended to be a substitute for adequate training and experience in the safety procedures for this device. Detailed descriptions of standard repair procedures, safety principles, and service operations are not included. It is important to note that this document contains some warnings and cautions against some specific service methods that could cause personal injury to service personnel, or could-, damage equipment or render it unsafe. These warnings do not cover every conceivable way in which service (whether or not recommended by SHINSUNG) may be done or possible hazardous consequence of each conceivable way, nor could SHINSUNG investigate all such ways. Anyone using service procedures or tools, whether or not recommended by SHINSUNG, must satisfy himself thoroughly that neither personal safety nor equipment safety will be jeopardized by the service method or tools selected. All information contained in this manual is based on the latest product information available at the time of printing. The right is reserved to make changes at any time without notice.

Enhanced Self Healing System 2


1.2. General Description of the Switch SPGAS is SF6 gas insulated, SF6 gas interruption load break switch and according to the control, it works as sectionalizer, RCS (Remote Control Switch) etc.

1.3. Ratings and Specifications Ratings and specifications of SPGAS is shown in “Table 1.” All type tests and routine test are done according to IEC Publication 694 and 265-1.

* Note: All types of products use the same interrupting chamber.

Type of Products SPGAS-15 SPGS-26 SPGAS-36

Basic Ratings

Maximum System Voltage 15 kV 24 kV 38 kV

Rated Continuous Current 400 A 400 A 400 A

Rated Frequency 50/60 Hz 50/60 Hz 60 Hz

Short Time Withstand Current ( rms) 10 kA/ 1sec 10kA/1sec 20kA/1 sec

Making and Breaking Capacity

Mainly Active Load Current 400A 400A 630A

Number of Load-break Operations 500 times 500 times 400 times

Short-circuit Making Current (peak) 25 kAp 25kAp 32.5 kAp

Number of Making Operations 5 times 5 times 5 times

Cable Charging Current 25A 25A 20 A

Line Charging Current 5A 5A 2A

Closed Loop Circuit Current 400 A 400 A 630 A

Transformer Magnetizing Current 22A 22A 22A

Over Load Current 800A 800A N/A

Power Frequency Withstand Current Test

Wet Condition- 10 sec (Ph- Ph, Ph-Eth, Across Interrupters)

45 kV 50kV 70 kV

Dry Condition - 1 min (Phase to Earth, Phase to Earth)

50 kV 60kV 70 kV

Dry Condition - 1 min ( Across Interrupter )

50 kV 60kV 80 kV

Impulse Withstand Current Test ( 1.2 x 50 μs )

Phase to Phase, Phase to Earth 110 kV 150kV 170 kV

Across Interrupter 125 kV 150kV 195 kV

Other Ratings & Specifications

Arc Extinction Medium SF 6 Gas SF 6 Gas SF 6 Gas

Insulation Medium SF 6 Gas SF 6 Gas SF 6 Gas

Minimum Creepage Distance : ( Porcelain Bushing )

550 mm 740 mm 960 mm

Minimum Creepage Distance (Epoxy Bushing and Silicon Boots )

615 mm 800 mm 1055 mm

Operation Performance

Closing/Opening Time < 0.7 sec < 0.7 sec < 0.7 sec

Mechanical Operations 5000 times 5000 times 5000 times

Operating Temperature -25 ~ 70° C -25 ~ 70° C - 25 ~ 70° C

Nominal Pressure (kgf/cm2 G, at 25°C) 1.0 1.0 1.0

Bursting Pressure (kgf/cm2 G) 4 ~ 6 4 ~ 6 4 ~ 6

Minimum Gas Pressure (kgf/cm2 G) 0.0 0.0 0.0

Leakage Rate (cc/ sec) 2.7 x 10 -6 2.7 x 10 -6 2.7 x 10 -6




Routine Tests The routine tests preformed according to ANSI C37.63, IEC 60265-1 and IEC60694 Clause 7. 1.3.1. Design and Visual Check The Switchgear and controlgear should verify its compliance with the purchase specification. 1.3.2. Mechanical Operation Test Requirements: Close/Open operations by manual and electric power should be made without trouble or malfunction. 1.3.3. Dielectric Withstand Test Applied parts: Main circuit to earth, Phase to Phase, Across the open Poles. Test Voltages: according to specification 1.3.4. Resistance of Main Circuit ANSI C37.63, IEC 60694 Clause 7.3 1.3.5. Gas Pressure Test Standard: SF6 Gas Pressure: 1.0 kg.f/.G ( 20°C). When checking gas pressure, consider ambient temperature, referring to the left Gas Pressure – Temperature Graph. 1.3.6. Gas Leak Test Permissible Leakage: Less than 2.7 × 10-6 cc/sec * Net Weight of SF6 Gas in the Tank SPGAS-26: about 2kg SPGAS-36: about 2.5kg 1.3.7. Wring Check CT: Polarity check, Accuracy Check. Standard of CT test: IEC60044-1 (600/1A, 0.5 class, 2.5VA) Permissible characteristic: Within ±3% or ±1A of Applied Current. Test procedure: Test in the range of 5~100% of rated primary current. * In case of Epoxy bushing, the partial discharge test should be done according to ANSI/IEEE C 37.71/ 5.7

Gas Pressure-Temperature of Pole Top LBS

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1.1

1.2

-30 -25 -20 -15 -10 -5 0 5 10 15 20 25 30 35 40 45 50 55

Temperature

kg . f/ cm2 . G



1.4. Receipt, Inspection, Storage and Test After the packing material has been removed, the Switch should be checked for possible damage caused by rough handling during transportation. At the same time check that all parts according to Packing Sheet are delivered. If the Switch is installed with a GAS PRESSURE GAUGE (METER) or GAS PRESSURE SENSOR, the gas pressure should also be checked. 1.4.1. Gas monitoring After unpacking the SPGAS Switch, the gas pressure has to be checked with a special tool (Gas Pressure Checker) through the gas filling valve placed on the side of the Switch. Contact SHINSUNG for further information on the special tool for gas pressure metering. If the Switch is installed with GAS PRESSURE GAUGE, it is easy to check. If the Switch is Automatic type including Control Unit, please check the gas pressure with connecting the Switch and controller. If the Switch has low gas pressure, LOW PRESSURE LED in the control box will be turned on. If the gas pressure is low, do not install the Switch and please contact SHINSUNG or local agent. 1.4.2. Storage and Transportation 1. All goods furnished shall be so seaworthy packed in wooden cases as to assure safe arrival at destination, withstanding such overseas hazards as rough handling and corrosion due to exposure to salt atmosphere and water spray. 2. All goods furnished shall be preserved, packed, crated, loaded and braced, in accordance with the best commercial export practices 3. The outside surface of packaging case shall be numbered by the supplier to designate the package and total number of the package being shipped: for example: 1/3: 2/3: 3/3 the first figure designating the package number and the second figures to total number of package in the shipment. 4. All packages will be marked with a description of connects and destination. Marking will be according to I.E.C's instructions. 5. Each good shall be packed with independent box and goods shall be loaded less than three-fold on container or ship.

1.4.3. Tests before Installation Please refer to SECTION 2.6 [S5 CONTROL SETTING DETAIL] and SECTION 2.7 [TEST]




1.5. Pole Mounting Installation 1.5.1. Site Procedure

1. Required Tools preparation 2. Assembling Mounting Bracket 3. Attaching Mounting Bracket (Triangle part only) to Switch 4. Disconnecting the Electricity Power Line and Bypassing 5. Installing Mounting Hanger Band on the Pole 6. Mounting Lightning Arrester on the Pole 7. Lifting and Mounting of Switch on the Pole 8. Control Mounting on the Pole 9. Earthing of Switch, Control and Lightning Arrester

10. Connecting Switch with Control by Control Cable. 11. On/Off Operation Test on the pole by Control and with Manual Operation Stick

12. Gas Pressure Check via indicator of the Control and Gas Pressure Gauge (or Meter) 13. Energizing Electricity Power Line 14. Open the by pass switch or remove the by pass cable. 1.5.2. Required Main tools are as following

- Equipment Lifting Device - Lifting Rope - Switch or Cable for Electricity Power Disconnection and Bypass - Wrench to tighten up bolts and nuts

1.5.3. Round Type 1.5.3.1. Assembling Mounting Bracket Assemble “Triangle” part of the Mounting Bracket and fix it to Switch.



1.5.3.2. Attaching Mounting Bracket to Mounting Hanger in the Switch Fix the Mounting Bracket (Tri-Angle Part only) to the Mounting Hanger in the Switch.

1.5.3.3. Disconnecting the Electricity Power Line and Bypassing With bypass Switch or bypass cable. 1.5.3.4. Installation of the Hanger Band on the pole Install two Hanger Bands on the pole. Lower Hanger Band should be installed below the Upper Hanger Band.

1.5.3.5. Lifting and Fixing the Switch by the Mounting Bracket to the Hanger Band For mounting on the pole, a four-point lifting is strongly recommended utilizing the Lifting Lugs in upper side of the Switch. The operating handle side of switch should face the pole for the safety of the lineman during the operation of bursting membrane. (Note) Exercise care during lifting to avoid damage to the bushings. The Switch must not be lifted or moved by the bushings. This may cause excessive stress on the bushings and damage the bushings.




1.5.4. Rectangular Type 1.5.4.1. Installation of the Mounting Cross-arm

For mounting switch on the pole, “①cross-arm” should be installed on the pole firstly using the “②plate

steel” as upper figure. 1.5.4.2. Lifting and Fixing the switch on the cross-arm

For mounting on the cross-arm, a four-point lifting is strongly recommended utilizing the Lifting Lugs in upper side of the Switch. The operating handle side of switch should face the pole for the safety of the lineman during the operation of bursting membrane.

Using the “③ Angle Steel” and “④ J bolt”, cross-arm and switch should be fixed tightness.

1.5.5. Installation of the Lightning Arresters and Earthing Installation of the lightning arrestors at both source and load side is highly recommended and in case of normal open point, it should be installed. The earthing wire of the arrestors, switch, control box should be T connected to one common earthing wire and it should be grounded with earthing resistance below 10Ω.



1.5.6. Lifting and Fixing the Switch by the Mounting Bracket to the Hanger Band For mounting on the pole, a four-point lifting is strongly recommended utilizing the Lifting Lugs in upper side of the Switch. The operating handle side of switch should face the pole for the safety of the lineman during the operation of bursting membrane. (Note) Exercise care during lifting to avoid damage to the bushings. The Switch must not be lifted or moved by the bushings. This may cause excessive stress on the bushings and damage the bushings. 1.5.7. Mounting the control box Fix the Control Unit on the pole at the position of more than 2m from the ground. 1.5.8. Control Circuit Connection 1. Connect the “Control Cable” to the receptacle on the mechanism box of the Switch body. 2. Connect the auxiliary power cable to the control box. (The self power type don’t use auxiliary power) 3. Control and power cable should be apart more than 20cm from the earthing wire. 1.5.9. Main Circuit Connection 1.5.9.1. For Lead Wire For lead wire, the NEMA pad terminal lug could be used for connection of the main circuit cable and lead wire bare terminal as following figure.

Legend

① M12 Hex-Head bolt

② Plate washer

③ Spring washer

④ M12 Hex-Head nut




1.5.9.2. For NEMA Terminal Following terminal lug is used for connection of the main circuit cable and bushing terminal if your bushing terminal is NEMA type bare terminal. (Universal Clamp Type Terminal and Eye Bolt Type Terminal are not applicable). This terminal lug is optional part, and it can be supplied upon request.

1.5.10. Auxiliary Power Source, battery and battery charger 1. External auxiliary power source

- Motor operation, 24V DC trip solenoid needs. External PT (more than 50VA) - The neutral of auxiliary power source should be grounded at the control box and it will be alone automatically.

- The battery should be checked periodically and will be changed every 3~5 years.

2. Internal auxiliary power source - If the sectionalizer is manual close type, then it can be trip through low energy tripper. - The low energy tripper charge the spring during open operation, hold and be ready to be released when it is closed.

It will be released by the low pulse energy. - The tripping energy can be charged through the CT’s and in this case the normal line current should be higher than 20A, and the minimum trip current should be higher than 100A.

Note : If the backup recloser trip according to extremely fast curve, it may need auxiliary power source

to charge the trip capacitor. - Internal auxiliary power source can be used to power the S5 control and to operate low energy tripper 6V nickel cadmium battery will be used.

















































































































Figure 1: Installation and Connection for Rectangular pole




Figure 2: Installation and Connection for round pole



1.6. Energizing Before energizing the SPGAS make sure that: 1. The gas pressure is checked. 2. The function of operating devices and position indicators is correct. 3. The line and earthing cables are connected with sufficient clearances. 4. The control power supply circuits are connected 1.6.1. Manual operation To close the sectionalizer, pull down the close handle several times (12~14times), then the sectionalizer will close quickly and maintain release free position. To open the sectionalizer, pull down the open lever, the sectionalizer will open. 1.6.2. Electrical operation In case of automatic motor operation, it can be close by the motor, and trip through solenoid. In case of self powered sectionalizer, the close will be done only by manually, but trip will be done through low energy tripping mechanism. The low energy tripper will be charged during open operation, and when the sectionalizer close, it will be released by low pulsed electric energy. The tripping power will be charged through CT

1.7. Operation safety 1.7.1. Hot line work procedure 1.7.1.1. Hot line installation Open the Load Break Switch By pass the line using the bypass switch or cable Install the Load Break Switch Close the Load Break Switch Disconnect the bypass cable or open the bypass switch 1.7.1.2. Hot line remove Close the Load Break Switch By pass the line using the bypass switch or cable Open the Load Break Switch Remove the Load Break Switch 1.7.2. SF 6 gas Pure SF 6 -gas is a nontoxic, nonflammable, heavy inert insulating and cooling gas of high dielectric strength and thermal stability. The SPGAS uses SF 6 -gas as an insulation and arc quenching medium. Arcing in SF 6 switchgear decomposes a small amount of the gas. Part of these decomposition products may be toxic. Under normal operating conditions these products are only present in small quantity and for limited periods of time inside the Switch enclosure, before they are absorbed by active absorbent. So during normal operation of the SPGAS the operator does not need any special protection.

1.8. Maintenance The SPGAS is maintenance free for the expected service life of the Switch. The tank is made of stainless steel, so there is no need for corrosion protection. Maintenance is needed only if gas pressure has




dropped below 50% of initial pressure level (please refer to Gas Pressure-Temperature relation graph).

1.8.1. Gas Low Locking Gas Low status could be checked through the “Low gas RED Target”(Refer to the following figure). If SF6 gas pressure drops below permissible pressure, gas low locking device block to prohibit the mechanical operation and electrical operation.

Before Gas Low Locking Device operation After Gas Low Locking Device Operation

1.8.2. Manual Locking SPGAS Sectionalizer has Manual Locking device to block the switching during the maintenance.

Before Manual Locking Device operation After Manual Locking Device Operation

1.9. Disposal of the Switch SPGAS includes valuable materials for recycling: stainless steel, copper, steel, and SF6-gas. Small amounts of gas decomposition products may be formed during the breaking operations. These are mainly eliminated by the absorbent inside the tank. However, some precautions are recommended to ensure safe handling of these materials. Local regulations, if any, shall be followed. The user can follow the procedure below: During the treatment, care should be taken to avoid contact of decomposition powders if contact wash the hand with water and cleaning fluids. Compressed air should not be used for removing powders. 1. SF6-gas can be removed from the Switch and be stored to the storage tank using SF6 recycling machine..



2. The tank shall be cut at open outdoors or in a well ventilated room. The absorbent should be neutralized. A suitable method is immersing in a solution of 1-3 kg sodium carbonate (Na 2 CO 3 ) in 100ℓ water for 24 - 48 hours. Contact with skin and eyes should be avoided, especially if higher concentrations of sodium carbonate are used. After neutralization the absorbent can be handled as normal waste. 3. All other parts of the Switch can be handled as normal metallic or plastic waste. It is recommended to remove the possible decomposition powder, if any, by a vacuum cleaner or by rinsing with clean water. The vacuum cleaner bags should be neutralized as the absorbent. For more information see IEC Technical Report 61634 (1995): ”High-voltage switchgear and controlgear – Use and handling of sulphur hexafluoride (SF 6 ) in high-voltage switchgear and controlgear”, chapter 6.5: ”Treatment at end of life of SF6 -filled equipment”.




Appendix 1: Safety Rules during Operation and Installation Operation Even the Switch is open, before touch the line, the line voltage should be checked whether it is alive or dead and the load side should be earthed. Installation 1. During moving or installation the Switch, the Lifting Lug should be used and otherwise the bushing can be destroyed. 2. Install the mounting bracket first, lift the Switch using the Lifting Lug and tighten the clamp using the hanger bolts and nuts. 3. The operating handle side should be faced with the pole, if otherwise the lineman can be injured during the operation of bursting membrane. 4. Connect the earth wire firmly to the earth terminal. The earth wire of Arrester, earth wire of Switch and earth wire of Control box should be T connected to one line of earth wire. Otherwise, Switch and Control will be dangerous. 5. Connect the control cable and power cable.



APPENDIX 2: Safety Rules and Instructions for Treatment of the Switch 1. SF6 gas leakage If the gas pressure meter is low, filling the SF6 gas can extend the operation periods of SF6 Switch. Even the SF6 Switch is tested at atmospheric gas pressure, the performance is not guaranteed in air-mixed SF6 gas. So, if the gas is low, it should be repaired. 2. Internal Arc If there is an internal short circuit, the pressure will be rapidly increased, and the pressure relief device will be operated to release the excessive gas pressure before explosion. If the pressure relief device (not resettable) is operated, the close, open operation will be prohibited by mechanically and electrically. In this case, the SF6 SWITCH cannot be used any more and have to be removed from the line. Normally the SF6 SWITCH will not exploded and the arc by-product powder will be remained inside the SF6 SWITCH case. But if there is toxic powder scattered outside, it should be gathered with the safety means not touch the skin directly. 3. Arc by products - Decomposed gas: SF4, S2F2, SO2, SO2F2, CF4, SiF4 - Arc decomposition products of SF6 with insulation materials: CF4, SOF4, SOF2, SO2F2, WF6, HF SF4 + H2O → SO2 +2HF 2S2F2 → 2SF2 + 4S → SF4 + 5S SO2 + H2O → H2SO3 SOF2 + H2O → CO2 + 2HF The decomposed gas and arc decomposition products of SF6 with insulation materials will be changed to HF and it is classified as an irritant gas. It can damage eyes and lungs so special care should be taken before and during dismantling the arced SF6 SWITCH. * Don’t touch the scattered powder with the bare hand. * Connect the hose to the gas filling value and exhaust the gas through soda-lime (CaO, NaOH ) water. * Good ventilating the working area. * Dismantle the component by the hand with rubber gloves. * Using the vacuum cleaner to take out the scattered power * Clear the case or component with soda-lime water first and then with clean water. * Dry well. * Reassemble new component. * Insert new composite zeolite. (10% of the weight of SF6 gas)




APPENDIX 3: Layout Drawing

A3-1. Insulated lead type(Example for 27kV)

No. Description No. Description

1 Main Tank 2 Bushing

3 Safety Membrane 4 Gas filling Port

5 Manual Trip Handle 6 Close/Open(I/O) Indicator

7 Manual Close Handle 8 Ground Terminal

9 Operation Counter 10 Receptacle for control

11 Low pressure Red Target 12 Manual Lock Handle

13 Insulated Lead Wire



A3-2. Bare terminal type




2. S5 Radial Sectionalizer Control

2.1 Overview The Shin-Sung S5 Sectionalizer are composed with SF6

load break switch and micro-controller based control.

The low power micro-controller and flux sensitive tripping

mechanism realize the self powered sectionalizer(CT

powered sectionalizer).

The S5 control use only the current element(no

directional protection) , but still it has many useful

functions than normal sectionalizer.

It has two tripping mode. One is counts trip and the other

is self trip for sensitive earth fault(I0, I0/I1) and open

conductor fault(I2/I1).

The counts trip function is the same with normal counting sectionalizer and the self trip will be possible up

to 630A and if the fault currents are higher than 630A, then it works as count sectionalizer.

The S5 control also has enhance smart grid operation functions as likes delayed fault pickup output, df/dt

counting for detection of island operation.

2.1.1 Counts trip

1) Phase fault

The phase minimum actuating current will be Set to 80~90% of backup protection device.

The programmable range will be 20 ~ 800A.

2) Ground fault

Normally, the ground minimum actuating current can not be lowered than normal maximum phase

current because of mis-operation during source side fault (3phase-4wire system).

But the S5 control can be more sensitive because it checks the increment of positive sequence

current (During source side fault, the unbalance current will be increased but the I1 will be decreased,

so the mis-operation will be avoided).

The programmable range will be 8~400A.

3) Sensitive earth fault

Modern backup protection device (CB, Recloser) have SEF protection functions, so the S5 control

also has SEF detection and counting function.

3 Phase 3 Wire system.

The neutral current of 3Phase 3Wire system is normally zero current.

The sensitive earth fault will be detected by zero phase current(I0) element




















2.1.1 Counts trip

1) Phase fault



2) Ground fault
































2.1.1 Counts trip

1) Phase fault



2) Ground fault
































2.1.1 Counts trip

1) Phase fault



2) Ground fault
































2.1.1 Counts trip

1) Phase fault



2) Ground fault
































2.1.1 Counts trip

1) Phase fault



2) Ground fault
































2.1.1 Counts trip

1) Phase fault



2) Ground fault
































2.1.1 Counts trip

1) Phase fault



2) Ground fault
































2.1.1 Counts trip

1) Phase fault



2) Ground fault
































2.1.1 Counts trip

1) Phase fault



2) Ground fault
































2.1.1 Counts trip

1) Phase fault



2) Ground fault
















The neutral current of 3Phase 4Wire system is not zero became of single phase to

ground load.

In this case the zero phase current ratio of I0/I1 should be higher than unbalance load ratio during

normal operation.

4) Negative sequence current

If the backup protection device has negative sequence current elements, then the sectionalizer also

should set negative sequence current.

The S5 control operate on 3I2 magnitude negative sequence current.


5) Counts

Maximum 4 counts can be programmable.

If the sectionalizer detects the fault current more than 1.25 cycle and if the current and voltage

disappear or if the frequency be changed(df/dt) more than threshold level, then the control makes unit

count.

The fault signal can last 3 second to finish the count after isolation of distributed generation.

If the current restore to normal load current, before completing the trip counts, then the counts will be

reset.

If the sectionalizer trips, then all the counts will be reset.

Once the sectionalizer is open by electrically or by manually, then the trip counts will be modified to

one count to open during preset interval to avoid pumping operation of backup device after line

maintenance work.

Count : 1, 2, 3, 4.

Reset time : 1 ~ 60 sec.

One count to open : enabled when the sectionalizer trips

Reset from successful reclose after 5 seconds.

6) Inrush restraint

The inrush restraint feature will be enabled when the sectionalizer experience load current before

current zero.

Once the inrush restraint features are engaged, then the phase, ground, sef, I2 minimum pickup will

be desensitized during the restraint duration.

The inrush restraint feature avoid mis-counting from transformer magnetizing inrush current during the

reclosing sequence of backup protection device.

Phase Multiply : 1X, 2X, …., 10X, block

Duration : 5 ~ 60 cycle




Ground

SEF

I2

Multiply : block

Duration : 1 ~ 10 sec

2.1.2 Self trip

The sectionalizer is load break switch, and the maximum interrupting current will be 900A.

The S5 control can be programmed to trip directly after timing if the currents are below 630A and if the

currents are higher than locking level(630A), then it just operate as counting sectionalizer.

This features can give great advantage during small ground fault or open conductor fault.

If there are SEF or open conductor fault in the line below 630A, then the sectionalizer can directly clear

the fault through the coordination between backup device and other sectionalizers.

1) SEF (Sensitive earth fault)

3 Phase 3 Wire system

Zero sequence current(I0) element will be used for sef protection.

The S5 control just use current element(I0), so the sensitivity will be limited compared with

directional sef protection(V0, I0).

- I0 : 1 ~ 50 A

- Time delay : 1 ~ 60 sec

3 Phase 4 Wire system

The ratio of zero sequence current to positive sequence current(I0/I1) with I1 increment can be

used for sensitive earth fault protection for 3 phase 4 wire system.

The ratio of I0/I1 should be set higher than normal unbalance load ratio to avoid mis-tripping

during normal operation

- I0 / I1 : 10 ~ 100 %


2) Open conductor fault

If the line is cut and the load side of open conductor touches the ground, the fault current may not be

detectable or if the line is just in-hang, there should be no ground current.

In this situation, the ratio of negative sequence current to positive sequence current will detect the

abnormal unbalance current and can protect the line from open conductor.

To avoid mis-operation during source side fault, ground fault and phase to phase fault, it will be

necessary to set long delay time than any other protection elements.

- I2 / I1 : 10 ~ 100 %


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