On LOad Tap ChangersrsV 7.3

TeChnICaL daTa

HHI – BSofia, Bulgaria

2013

EA 759/13 ENG

2

Contents

1. Basic characteristics .......................................................................................................................... 3

1.1. Basic technical data .............................................................................................................. 31.2. Rated through current (Iu), rated step voltages (Ui), rated switching capacity (PstN ) ........ 41.3. Electrical and mechanical endurance ................................................................................... 51.4. Insulation level ..................................................................................................................... 5

2. Review of the RSV 7.3 types ................................................................................................................6

2.1 Main dimensions ................................................................................................................... 62.2. Number of steps ................................................................................................................... 7

3. 3. Basic connection diagrams .........................................................................................................7

3.1. Designation and basic connection diagrams ......................................................................... 73.2. Examples of basic connection diagrams ............................................................................. 10

4. 4. Appendices .................................................................................................................................... 13

4.1. Overall dimension drawings of OLTCs ............................................................................. 134.2. Additional drawings of OLTCs .......................................................................................... 13

Notes:

1) This technical data catalog is intended to be used by transformer designers as well as othertechnical personnel responsible for maintenance, diagnostics, and operation of OLTCs.

2) HHI-Bulgaria reserves the right to make changes in the overall dimension drawings andconnection diagrams without prior notice. Updated drawings are provided as part of thetechnical documentation received by the customer at the time of the product delivery;updated drawings can be provided also to potential customers on request.

3) TheOLTCismanufacturedaccordingtothespecificdataintheorderspecificationsheetfilledinbytheclient.

4) HHI-Bulgaria is not responsible for the client’s selection of an OLTC that meets the re-quirements of a given transformer.

3

1. Basic characteristicsThe OLTCs of Hyundai Heavy Industries Co. Bulgaria (HHIB) meet the requirements of the IEC 60214-1:2003 standard.1.1. Basic technical data

Table 1: Basic technical dataOLTC type RSV7.3

Number of phases and application Single phaseMaximum rated through current (A)

Short circuit withstand current (kA)

r.m.s. value, 3 sec. durationpeak value

Maximum rated step voltage per phase (V)Rated switching capacity (kVA)Rated frequency (Hz) 50..60

Insulation to earth

Highest voltage for equipment Um (kV, r.m.s.)Rated separate source AC withstand voltage, 1 min duration, 50 Hz (kV, r.m.s.)Rated lightning impulse withstandvoltage(kV,1,2/50μs)Rated switching impulse withstandvoltage(kV,250/2500μs)

Number of operation positions max. of 107 (1200A – max. of 89)

Tap selectorTwo tap selector sizes (M, N) are available corresponding to the requirements of the voltage stress across the regulating winding. The tap selector insulation level can be chosen independently from the maximum operating voltage to earth. For the test voltages, see Section 1.4.

Diverter switch oil compartment Pressure-proof up to 0.3 bar (continuous differential pressure); testing pressure – 0.6 bar; vacuum-proof for drying

Siphon for draining the oil from the diverter switch oil compartment Basic design – left or right

Drying In vacuum autoclave – max. of 110°CKerosene vapor-phase drying – max. of 125°C

OLTC type 400, 550A 700A 1200ATap selector size M N M N M NWeight in kg (approximately) 280 288 290 298 300 320

Displacement volume in dm3 (approx.)

72,5 kV 173 183 177 187 181 191123 kV 183 193 187 197 191 201170 kV 193 203 197 207 201 211245 kV 205 218 212 222 216 226300 kV 220 232 227 237 231 241

Oilfillingcapacityofthediverterswitch oil compartment Vs in dm3 (approx.)1)

72,5 kV 105 125123 kV 120 135170 kV 135 155245 kV 150 170300 kV 160 180

Notes: 1) Minimum volume of the conservator considering the temperature-induced oil expansion when thetemperaturechangesfrom-30°Cto+100°C:ΔV=0.1Vs+5(dm3)The RSV 7.3 OLTC can operate with a rated load at oil temperature from -25º C to +115º C.

1.2. Rated through current (Iu), rated step voltages (Ui ), rated switching capacity (PstN )

400 550 700 12006 8 10 15

15 20 25 37,53500 3000 3200 30001400 1650 2240 3600

72,5 123 170 245 300

140 230 325 460 460

350 550 750 1050 1050

- - - 850 850

EA 759/13 ENG

4

The maximum values of the through current Iu and its relevant values of the step voltage Ui and rated switching capacity PstN are shown in Table 2.

Table 2: Rated through current (Iu), rated step voltages and rated switching capacity (PstN)OLTC type RSV 7.3

Ium (A) 400 550 700 1200Ui (V) 3000 2700 2700 2700

PstN (kVA) 1200 1485 1890 3000

The rated through current (Iu) and its relevant step voltage (Ui) are determined from the curve of the rated switching capacity (Fig. 1).Fig. 1: Rated switching capacities (rated through current Iu (A); rated step voltages Ui (V))

In the case of overexcitation of the transformer, the maximum step voltage can be increased with 10% under the condition that the breaking capacity is limited to its rated value. The maximum switching capacity Pst max is the maximum power at which the OLTC can switch the regulating winding from one tap to the next. According to the IEC 60214-1:2003 standard, Section 5.2.2.2, the maximum switching capacity is confirmedwithtwicethemaximumratedcurrentanditscorrespondingstepvoltage,andisequaltoatleasttwice the rated switching capacity:

Pstmax=2Ium.Ui=2PstN

ThespecificcommutationregimesareclarifiedinthetechnicaldatacatalogforallHHIBonloadtapchangers.

5

1. 3. Electrical and mechanical enduranceTable 3 gives the average values for the number of switching operations till inspection of the diverter switch and replacement of the vacuum interrupters. These values have been obtained as a result of experimenting withrealloadsundermaximumratedthroughcurrentIum(A),ratedstepvoltageUi(V)andcosφ=1.Detailed information in this regard can be found in the RSV 7.3 Installation and Operation Manual.

Table 3: Electrical and mechanical endurance

OLTC RSV 7.3400, 550 and 700 A 1 200 A

Number of switching operations till inspection (oil replacement) 250 000 150 000Number of switching operations till replacement of vacuum interrupters 500 000 500 000

Mechanical endurance - number of switching operations 500 000 500 000

1.4. Insulation levelThe insulation level of the OLTC is determined by a number of withstand voltages. The rated withstand voltages to earth are given in Table 1. These voltages are determined by national and international standards.Theinternalinsulationisdimensioneddependingonthevoltagesdefinedbythetransformerwindingtaps to the different parts of the selector, change-over selector and the diverter switch. Fig. 2 shows the main connection diagrams with the typical insulation distances.The withstand voltages from the different insulation distances are given in Table 4. In order to select the proper OLTC type, it is necessary that these voltages correspond to the voltages that occur during the lightning impulse test, the induced voltage test and the power frequency voltage test of the transformer. The least favorable position of the OLTC should be taken into account. The insulation to earth and the tap selector insulation size are not mutually connected and can be selected inaccordancewiththespecificrequirements.

a0=betweentheoperatingandtheselecteddiverterswitchtaps;a1=betweenthefinetapselectorcontactsofthewindingforonestep (closed or open);a=betweenthebeginningandtheendofafinetapchangerwinding and between the closed K-contact and any point of the finetapchangerwinding;c1=betweenanycoarsetapsforaphaseandthediverterswitchlead;d1=betweentheclosedcoarsechange-overselectorcontactanditsadjacent contact;d2=betweenopenadjacentcoarsechange-overselectorcontacts;d3=betweenthebeginningandtheendofallcoarsetaps;

Fig. 2: Insulation distances of the transformer windings

d

dd

d

ka

a

a

caa

0

11

11

3

2

1

EA 759/13 ENG

6

Table 4: Withstand voltages

Insulation distances

Rated withstand voltages (kV)Tap selector size M Tap selector size N

1.2/50 µs 50Hz – 1min 1.2/50 µs 50Hz – 1min

a0 130 40 130 40a1 130 40 130 40a 350 100 410 120c1 450 130 450 130d1 420 120 420 120d2 420 120 420 120d3 450 130 450 130

2. Review of the RSV 7.3 types

2.1. Main dimensions 1)

Table 5: Main dimensions

Um

hTap selector

size MTap selector

size N

400,550,

700 A1200A

400,550,

700 A1200A

72,5 1429 1919 1539 2029123 1629 1968 1738 2078170 1728 2118 1838 2228245 1828 2318 1938 2428

Fig. 3: Main dimensions

1) Fortherestofthedimensions,seeDrawings№996.2e&1037.2e.

O540

865

h

7

2.2. Number of stepsTable 6 shows the number of the standard operation positions (n). For special orders, the number of operation positions can be up to n-1, that is one position less than the number of positions indicated in the table.

Table 6: Number of standard operation positions (n)Number of coarse steps

Tap selector divisions 2G 3G 4G 5G

14 41 55 69 83

16 47 63 79 95

18 53 71 89 107

3 Basic connection diagrams3.1 Designation and basic connection diagramsFig. 4, 4a, 4b and 4c showthebasicconnectiondiagrams.Allofthemshowthemomentwhenthefinetapwinding is turnedoff for thefirst timeand theselector is running todecrease thenumberof theeffective transformer turns.

Fig.4: Basic connection diagrams

EA 759/13 ENG

8

Fig. 4a: Basic connection diagrams

9

Fig. 4b: Basic connection diagrams

EA 759/13 ENG

10

Fig. 4c: Basic connection diagrams

3.2 Examples of connection diagramsFig. 5 and Fig. 6 show in detail two basic connection diagrams that are commonly used.

11

Fig. 5: Connection diagram 16.79.1G4

EA 759/13 ENG

12

Fig. 6: Connection diagram 18.107.1G5

13

4. Appendices

4.1. Overall dimension drawings of OLTCs

RSV 7.3 I 400/550/700/800 – 72,5 – 245/M(N) OLTCs №1037.2e

RSV 7.3 I 1200 OLTCs №996.2e

4.2. Additional drawings of OLTCs

Pressure relief device of the Qualitrol type №174.Qe

FlangesConfigurationofRS9.3/RSV9.3andRS7.3/RSV7.3 №999e

RS 7.3 / RSV 7.3 – standard OLTC set №1052e

RS 7.3 / RSV7.3 – driving shafts arrangement №M6.3.100.003.00eSh.1 and Sh.2

Please note: The overall dimension drawings and the basic connection diagrams can be changed without prior notice.

ON LOAD TAP CHANGERSRSV 7.3 I 400,550,700,800 – 72,5...245/M(N)

(MAX 107 OPERATING POS.)

1037.2e

2013

ON LOAD TAP CHANGERSRSV 7.3 - I - 1200

max 89 operating position

№996.2е

2013

PRESSURE RELIEF DEVICETYPE “QUALITROL”

№174.Qе

2013

ON LOAD TAP CHANGERS RS7.3/RSV7.3; RS9.3/RSV9.3

Flanges Configuration

№999е

2013

ON LOAD TAP CHANGER RS7.3 AND RSV 7.3STANDART SET

№1052е

2013

ON LOAD TAP CHANGER RS7.3 AND RSV 7.3DRIVING SHAFTS ARRANGEMENT

№M6.3.100.003.00e

2013 Sheet 1/2

ON LOAD TAP CHANGER RS7.3 AND RSV 7.3DRIVING SHAFTS ARRANGEMENT

№M6.3.100.003.00e

2013 Sheet 2/2