MEDIUM VOLTAGE ENERGY TRANSMISSION SYSTEM

Transcription

1 GENERAL LEAFLET MEDIUM VOLTAGE ENERGY TRANSMISSION SYSTEM THOUGHTS ON THE DISTRIBUTION OF ELECTRICAL ENERGY T I T /07/2011

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3 CONTENTS GENERAL : The receivers. p. 4 Network transformer in a pit or compact substation. p. 4 The LV sub network..p. 5 The TIT transportation network p. 6 Earthing scheme p. 7 Pipes calculation....p. 9 Transformer substation.. p. 10 Dimmer. p. 10 TIT network control.. p. 10 TOOLS :. p. 11 APPLICATION EXAMPLE :.. p. 12 APPENDIX : Number of lamps per TIT / LV network transformer... p. 18 Choice of the LV cable section. p. 19 Dimensions of prefab concrete pits... p. 20 Choice of MV cable section. p. 21 Appearing impedance of MV and LV cables... p. 23 Voltage drop calculation... p. 24 Choice guide of transportation voltage level to supply an end of line load.. p. 26 Choice of 950 V cable section... p. 29 GLOSSARY LV MLV HCP MV NP TIT : Low Voltage. : Maximum Low Voltage. : High Cutting Power. : Medium Voltage. : Nominal Power. : Gathers MLV and MV Voltages Standards : NFC from March 2007, NFC from 1978 This document is not an exhaustive study, but is merely a collection of observations and advice aimed at aiding specialists. Augier takes no responsability for use of advice on all previous and future installations. 3

4 TIT Installation Conception GENERAL : The Receiver : The types of power receivers can be very varied. The parameters below are used to characterize them. Some are directly associated with the type of power receiver and so do not need to be recorded. The type of receiver. Power supply voltage and tolerances. Phase system (single or three phase). Power rating, start-up characteristics (overcurrent, cycle and duration). The type of use: continuous, cyclic or occasional. The conditions for simultaneous operation and simultaneous start-up of several power receivers, if necessary, both in steady state and at start-up. The degree of continuous operation requirement. NETWORK TRANSFORMER IN A PIT OR COMPACT SUBSTATION : In the chapter below, the transformers of network or mini substation will be called "step down sub-station ". The step down sub-station is used to supply a power receiver or group of power receivers. The locations of the step down sub-stations and the configuration of the power receivers are determined according to conditions in the field, relating to installation of these stations and laying of LV lines, by an economic optimization calculation that takes into account the costs of the stations and LV cables, as well as the installation costs. The step down station s power rating is determined by adding together the power of the supplied power receivers. In addition the following factors will be taken into account : Power efficiencies and factors, accessory power consumption, and possibly an incrementation factor, to determine the theoretical current. Permissible limits for power supply voltage when operating in steady state and at start-up. Ambient temperature conditions. The current/voltage characteristics of the power consumers, the predictable deterioration in electrical efficiency due to ageing, the possible extensions, to determine a working current. The start-up characteristics to define a start-up current, possibly after application of an incrementation factor. The coupling of the step down transformer will be single or three phase, depending on the design of the LV sub-network (see below). 4

5 There are two possible types of step down sub-station, depending on its power and installation conditions : Either a TED step down station, normally installed as infrastructure in an inspection pit (power limited to 160 kva). This is an operational complete unit, equipped with two plug-in TIT terminals to ensure line continuity to the downstream sub-station, comprising the TIT/LV transformer, the TIT and LV protection, and the LV output which can be either a 6 meters cable or a plug-in terminal. Pits of watertight transformers must offer an inside volume at least equal to four times the transformer volume. In addition, they must allow cable inputs and their connection with respect to curving radius values indicated by the cable constructor. Transformers pits can be prefab. They must be composed of a grill equipped with a locking device by a special screw, which forbids the access to the transformer until the TIT input is not opened at the installation origin, put in circuit breaker and on earth (according to NF C standard for road lighting installations). Or a compact internal or external station, depending on the installation conditions, comprising a dry varnish impregnated transformer. Outdoor type compact substations are designed to be installed on a concrete base, with cable output and input from the ground, under plastic wrapping. The step down sub-stations are equipped with the following electrical protection : MV side : one or more fuses whose rating(s) is/are determined according to the characteristics of the step down transformer. However this protection will only be installed when there are several TIT/LV sub-stations linked to a step up station, because otherwise it is impossible to ensure selectivity with the step up transformer s TIT protection. LV side : The LV circuit breaker whose rating must be greater than the working current of the supplied power receivers. In the transformer : thermal probes connected to the LV circuit breaker. THE LV SUB-NETWORK Its layout depends on the terrain s characteristics, the road layout, the possibilities for underground crossings, the locations of natural or man-made obstacles. A ground scheme must be chosen in accordance with current legislation and the continuous operation requirements. A certain number of rules will be defined as a result of this choice. These rules will determine whether or not it is necessary to install differential protection or insulation monitoring devices on the step down station, and to determine the cross-section of the LV cables, called LV feeders. These rules are defined in a general way in the standard NF C and when appropriate also in specialized standards such as C or the C guide for public lighting. They guarantee : Feeder protection against excess current Personnel protection against indirect contacts 5

6 Concerning short circuit protection, as described in standard NF C (art and comments), the LV circuit breaker of the step down sub-station that ensures overcharge protection is also considered to provide short circuit protection at the same time. For road lighting installations, the C practical guide nevertheless recommends that the minimum short-circuit rule should be satisfied, and suggests possible reductions in the line cross-section without any additional protection device. The LV sub-network of a step down sub-station as we have designed it does not comprise any reduction in cross-section, and so the case described in guide C does not concern us. Let us consider for a moment the possibility that a short-circuit is not detected by the magnetothermal tripping device, therefore creating a continuous fault. In such a case the thermal probe protection installed in our TIT/LV sub-stations is capable of eliminating the fault, regardless of whether or not it is dangerous for the LV feeders. Given these considerations, it is not necessary to satisfy the minimum short-circuit rule, concerning LV networks supplied via TED type or compact type step down transformers. THE TIT TRANSPORTATION NETWORK The number of outputs, their layout : They are determined according to the planned locations for the different TIT/LV substations, the possibilities offered by the terrain for trench excavation, road crossings and civil engineering works. As far as possible we will make every effort to achieve balanced outputs, and when appropriate we will consider the possibility of looping-in 2 outputs together, for repair purposes. Any given output can be implemented as a single antenna, or with T branches or in a cross. The TIT transmission network obtained in this way can also be linear type, star, loop or meshed, or a combination of these different types. The general output characteristics : The output phase system must be three phase, in order to power the three phase TIT/LV sub-stations. In this case, the preferred TIT voltage will be 6600 V, 5500 V or 950 V. It should be noted that single phase TIT/LV sub-stations can however be installed on this type of output. The transformers corresponding to this configuration comprise a phase selector making it possible to balance the output charge distribution on the three phases. If the TIT/LV sub-stations are all single phase, the output can be single phase or three phase. In most cases, the single phase solution with a preferential voltage of 3200 V or 950 V is the most economic and the easiest to implement. However, when the outputs are of a considerable length, the three phase solution with single phase TIT/LV sub-stations can be selected, to reduce line drop and generally satisfy all the rules stipulated in the standards. 6

7 Earthing scheme : The scheme will be chosen from the TNRC or TNRS schemes, that in general are the most suitable (defined in conformity with standard UTE D17 200). The neutral TIT is linked directly to ground at the installation origin. When the outputs are single phase either scheme can be selected, and the only difference is that in the TNRC scheme the TIT neutral is grounded at each TIT/LV substation, and in the TNRS scheme it is not. If the outputs are three phase the ground scheme has to be TNRS, since the neutral is not distributed. The earth connections must be made : Individual earth connections. Connection to a bare copper conductor with à minimum cross section of 25 mm² which serves as both the earth connection and an equipotential link between the luminaires. Common earth point with the luminaires connected by insulated cables. The second solution, the earth network for bonding the equipment earths comprises a bare copper conductor with a minimum cross sectional area of 25 mm² burried directly in the ground corresponding to the TIT line, is the one we recommend because it allows to obtain better resistance to earth values. Since the 1 st of October 2003, the NC C standard imposes this second solution for road lighting. The earthing circuit this way will enable to connect : The earth point of the TIT/LV transformer. The neutral of TIT winding in a generalised earth scheme (TNR-C). The safety grid in the transformer housing. One point of the low voltage. The conducting parts of any equipment that can be accessed at the same time as that of the road lighting system. For the substation, the earth connection must be a bare conductor 25 mm² made of copper buried at about 50 cm from substation. This conductor will be depth of about 40 cm, the iron framework of the station concrete pedestal being, in that case, linked to this conductor. The transformer neutral must be connected to the earth connection to realise a TN scheme. The substation earth bonding must be connected to the earth connection : The earths of all circuits in the substation. The screens of the cable. The transformer tank. The switching devices. The metal pipework and ducting. However, the doors of the building and the metal ventilation slots should not intentionally be bonded. 7

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9 CALCULATION OF FEEDER CROSS SECTION : This calculation will be determined by the maximum authorized voltage drop, by adding together the values from the TIT and LV voltage drops. The total voltage drop must not exceed 6% for a road lighting installation, and 8% in other cases. However it will be necessary to check that the protection fuse located at the circuit origin (at the step up station) makes it possible to satisfy the stipulated rules, i.e.: Protection against indirect contacts. Protection against over charges. Protection against excess current. If necessary a differential relay can be installed, if a TNRS scheme is used, to make it easier to satisfy the rules mentioned above. 9

10 THE SUBSTATION : The substation will be step up or step down type. Implementation : As far as possible, the substation will be installed in the center of the installation. However, installation off-center is perfectly acceptable when an TIT transmission voltage is used. The implementation will be determined according to the possibilities for installation offered by the site. Nominal Power : Nominal power is determined by the sum of step-down sub-station powers, taking into account the extension possibility or non-project and by retaining a standardized transformer power. Step-up stations will be used for powers from 5 to 160 kva for easy projects, with most often, only one TIT network departure. Step-down stations will be used for powers from 160 to 1250 kva which intensities are compatible with the circuit breaking bearing of pluggable terminals of step-down watertight transformers. For service continuity reasons, it is possible to retain a transformation station equipped with two identical power transformers. One transformer supplies the whole installation in case of the failure of one of the transformers. Coupling: The type of step-up transformer coupling depends on which phase system is selected for the TIT outputs. In the case of three phase outputs, it will be three phase. In the case of single phase outputs, it can be three phase, three/two phase, three/single phase or single phase: Three phase can be selected if there are three outputs or a multiple of three. These outputs must be virtually balanced. Three/two phase will be selected if there are two outputs or a multiple of two. These outputs must be virtually balanced. Three/single phase is the only coupling that corresponds to all the possible situations and that allows looping of 2 outputs for repair. It implies that the primary currents will not be balanced. TIT networks control : For networks only composed with lamps, inputs will be temporary, off during the day, controlled by a photo electrical cell doubled with an astronomical clock. The control will also be realizable by current carrier using the STEP II system. For networks supplying receivers different from lamps, inputs will be permanent. For mixt networks, inputs will be permanentthe lighting control will be made by current carrier. Dimmer : It is better to put, in the transformer station, a dimmer regulator to reduce the power of lamps during weak traffic hours.the dimmer regulator allows, during hours when reduction happens, consumption savings. 10

11 TOOLS : In the appendix, you will find all the documentation to help you with the realization of a quick TIT study : Case of the supplying of receiver units at a line end : The guide for the choice of the voltage level transportation to supply the end of line load. Case of the supplying of receivers uniformally spread, road lighting case : Annex : number of lamps for each TIT/LV lighting transformer. Choice of the LV cable section downstream of the step-down watertight transformer. Concrete prefab pits best dimensions for step-down transformers installation. Choice of the MV cable secton for single-phase and three-phase networks, for a 2 or 3 % voltage drop. Choice of the MLV cable section for single-phase and three-phase networks, uniformally spread load at the end of the line. Calculation formula enabling to control the choices with the annex usage and AUGIER. 11

12 APPLICATION EXAMPLE : SUPPLY FOR A ROAD LIGHTING «LV/TIT» INSTALLATION PROJECT : In the following section, by means of an example we show how to determine rapidly the main sections constituting a preliminary study for a road lighting project using TIT transmission voltage. We draw the reader s attention to the need to check or further specify the results obtained using the method set out below. This is because, apart from the approximate nature of this example, it is not intended to provide an answer for every situation or for every special case that may arise. The aim of the project we have used in this example is to define the power supply for road lighting of a road. Determination of the basis for calculation : The calculations are to be performed on the basis of the information to be supplied below : Number of power consumers and type : the installation comprises one lighting pole every 35 m, each fitted with two 250W high pressure sodium lamps. Installation of the lighting poles : The lighting poles are set up in the central reservation. Network length : The total length of the installation is 4 km. Station location : The station is located in the middle of the installation. Supplied voltage level : Three phase 400 V Installation conditions : Maximum ambient temperature 40 C Altitude less than 1000 meters Internal installation Operating principle : This substation will be supplied from a low voltage three phase 400 V power source, via the mains network, and will transform this voltage into a transmission voltage to be determined. STEP 1 : Determination of the network s rating power : Determination of number of the lamps : The installation s power is determined by the number and type of the lamps used, whose mean characteristics are described in guide C Application : Number of lamps : 230 Type and power : 250 W HPS Determination of the road lighting transformers power : Their power depends on the number of lamps powered by the network transformer. The transformers are used in conformity with standard NFC , which limits their use to 0.8x NP where NP is the nominal power. 12

13 As a rule we will use transformers with : 3 kva in exchangers where the lamps will be distributed in all directions. 5 kva for the current sections. 10 kva for the pole power supplies. Other power supplies available according to use. The number of lamps supplied by a transformer is given in our table «Number of lamps by transformers TIT/LV» LAMPS TYPE HPS LAMPS Power (W) Power (VA) TRANSFORMER POWER RATING NUMBER OF LAMPS BY TRANSFORMER Nominal power Using power 400 VA 320 VA VA 500 VA kva 0,8 kva kva 1,6 kva kva 2,4 kva kva 4 kva kva 8 kva Application : 5 kva with a maximum of 12 lamps HPS 250 W TIT NETWORK Substation TIT/LV 5 kva Substation TIT/LV 5 kva 35 m 12 x HPS 250 W Determination of the network s total power : The total power depends on the number of network transformers Application : 20 network step-down transformers 5 kva, total power = 100 kva. STEP 2 : Determination of the low voltage cable cross-section : In general, the TN ground scheme will be used. The cable cross-section depends on : The length of the low voltage sub-network seen from the transformer side, for a transformer placed in the middle. On the protector block rating (LV circuit breaker). 13

14 The cable section is shown in the «Low voltage cross section determination» Rating power (kva) Maximum length (m) for one side of the transformer Protected against indirect contacts with 1 extr. MALT Cross section (mm²) , , Application : Length of the LV sub-network on one side of the transformer : 87.5 meters + 5 meters vertical section per pole. Total length = meters. The cable cross section is 2 x 4 mm². TIT Network Substaion TIT/LV 5 kva Substation TIT/LV 5 kva 35 m LV Câble 2x 4mm² 102,5m 12 x HPS 250 W STEP 3 : Determination of the distribution type and level of transmission voltage : The distribution may be : Three phase 5500 V for long charged networks, or networks that comprise three phase power receivers. Single phase 3200 V for power values up to 100 kva, for installations that only have one output. Two phase 3200 V for power values up to 100 kva, for installations with two balanced outputs (2 x 50 kva). Application : The substation is placed in the center of the application with 50 kva to supply on each side. Two phase 3200 V distribution. STEP 4 : Determination and selection of Road lighting Transformers : The transformers are determined according to : The transformer coupling. The type of distribution network (single phase or three phase). The type of cable used. 14

15 Application : Single phase transformer for single phase network, using two pole concentric cable TER MM, TED MMX or Modulo BI type. Please refer to the transformer documentation available. STEP 5 : Determination of the MV cable cross-section The choice of cable cross-section depends on the power and length of the network. The length is basically limited by the line drop. Protection is ensured by choosing a protection. The cross-section is given in appendix «MV cable cross section determination», which takes into account a maximum MV line drop of 2%, compatible with the total limit of 6% for MV and LV. Power Rating Cross section (mm²) (kva) Application : The 3200 V cable cross section for supply 50 kva per output on the Length 2000 meters is mm². Single phase network 3200 V Two pole concentric cable mm² TED MMX 5 KVA 3200 V/230 V TED MMX 5 KVA 3200 V/230 V 35 m LV Cable 2x4 mm² 12 x HPS 250 W Step 6 : Determination of the substation : Determination of the substation power : The main transformer s power must be at least equal to the sum of the nominal powers of the road lighting transformers, supplied downstream (NFC ). We will choose a standard power, chosen in the range : 25, 50, 63, 80, 100, 125, or 160 kva Application : In order to have an extension possibility, the retained power is 125 kva. 15

16 The substation will be equipped with : A LV counting table. A step-up set protection and control table. A power transformer, three-two phases, 400 V/3200 V with a 125 kva power rating. The different features that constitute the protection table are determined depending on the transformer s characteristics and dimensioned during the definitive study. Conclusion : This fore-study enables to difine the heights conforming to NFC et NFC standards with respect to a global voltage drop of 6% maximum. All the features of the fore-study, will have to be confirmed by a more precise calculation, in order to also precise and confirm the values obtained. Indeed, for our application, the 3200 V cable section retained would be mm². 16

17 APPENDIX 17

18 NUMBER OF LAMPS FOR EACH TIT/LV NETWORK TRANSFORMER : Determination of the maximum number of lamps to use depending on the transformers power, conforming to the standard recommendations NFC , NFC and C guide. TYPE OF LAMPS HIGH PRESSURE SODIUM LAMPS MERCURY LAMPS Power Rating (W) Power Rating (VA) TRANSFORMER POWER RATING Nominal Power Useful Load NUMBER OF LAMPS PER TRANSFORMER 400 VA 320 VA VA 500 VA KVA 0,8 kva KVA 1,6 kva KVA 2,4 kva KVA 4 kva KVA 8 kva TYPE OF LAMPS LOW PRESSURE SODIUM LAMPS METALLIC IODIZED LAMPS Power Rating (W) Power Rating (VA) TRANSFORMER POWER RATING NUMBER OF LAMPS PER TRANSFORMER P. Nominale P. utile 400 VA 320 VA VA 500 VA KVA 0,8 kva KVA 1,6 kva KVA 2,4 kva KVA 4 kva KVA 8 kva For information : Lamps lifespan is about to hours. The lighting functionning time, in France, is hours. 18

19 DETERMINATION OF THE LOW VOLTAGE CABLE CROSS SECTION : Single-phase network transformer Maximum lengths in meters of the pipes, single-phase 230 V, TN scheme, with the windings edge linked to the earth, protected against indirect contacts and overloads. Case of single-phase transformers protected by a circuitbreaker associated with a thermical probe. Calculations established with a protection conductor of 1 x 25 mm². Power Rating (kva) Intensity (A) Under 230 V Protection rating Low voltage Maximum length (m) one side of the transformer Protected against indirect contacts with an earthing plug edge Section (mm²) C60 N - 10 A (B) C60 N - 10 A (B) C60 N - 10 A (B) C60 N - 16 A (B) C60 N - 20 A (B) C60 N - 25 A (B) C60 N - 32 A (B) C60 N - 40 A (B) C60 N - 50 A (B) C60 N - 63 A (B) Non standard section Maximum lengths (in meters) of single-phase pipes in scheme TN, protected against indirect contacts : L = k U S / (R (1+m)Ind With : k = 0,8 U = 230 V S = LV cable section R = 0,023 m = S / 25 Ind = 5 x circuit-breaker rating Maximum lengths (in meters) of single-phase pipes in scheme TN, protected against circuit breakings : In the case of transformers protected by a circuit-breaker associated to a thermical probe, rule not to be verified. L = K U S / (2 Rcc ind) With : K = 0,8 Rcc = 0,023 (Protection by circuit-breaker) Ind = 5 x circuit-breaker rating 19

20 DIMENSIONS OF CONCRETE PITS Depending on the existing pit, for TER, TED and MODULOBLOC Transformer TED MMX Modulobloc bi or tri TER MM ou MT TED MMX TED MTT Modulobloc bi or tri Every TED type With elbow terminals or modulobloc Power Rating 0,4 à 6 kva jusqu à 6 kva 1 à 10 kva 8 et 10 kva 2 à 10 kva 8 et 10 kva 16 à 32 kva Dimensions (inside) concrete pits (mm) L l H Approx. Weight (kg) Models EP EP L5T INDICATIVE DIMENSIONS OF CONCRETE PITS Minimum dimensions (with a 3x25 mm² cable) for TED > 10 kva and TEH Transformer TED MMX TED TTT TED MMX TED MTT TED TTT TED MMX TED MTT TED TTT Power Rating 16 kva 5-10 kva 25 kva kva 16 kva 25 kva 50 kva kva Concrete pits dimensions (mm) L W H (b. straight) H (b. elbowed) TEH TTT 50 kva TEH TTT kva

21 DETERMINATION OF THE MV CABLE CROSS SECTION 3200 V single-phase network Compatible with a 2 % voltage drop : Uniformally spread power rating, maximum network departure lengths in meters. Cross Section (mm²) Power Rating (kva) Impedance at 85 C Compatible with a 3 % voltage drop : Uniformally spread power rating, maximum network departure lengths in meters. Power Rating Cross Section (mm²) kva

22 Compatible with a 4 % voltage drop : Uniformally spread power rating, maximum input lengths in meters. Cross Section (mm²) Power Rating (kva) Impedance at 85 C Three-phase 5500 V network, compatible with a 2% voltage drop Cross Section (mm²) Power Rating (kva) Impedance at 85 C

23 Three-phase 5500 V network, compatible with a 3% voltage drop Cross Section (mm²) Power Rating (kva) Impedance at 85 C 3,9 2,36 1,49 0,94 0,66 0, Three-phase 5500 V network, compatible with a 4% voltage drop Cross Section (mm²) Power Rating (kva) Impedance at 85 C 3,9 2,36 1,49 0,94 0,66 0,

24 LV AND MV CABLES APPEARING IMPEDANCE MV cables : Table valid for concentric bipolar and tripolar cables. Given values for cables calculated at an average temperature of 50 C. Cross Section (mm²) Impedance ( / km) LV Cables : Table valid for armed LV bipolar and tripolar cables. Given values for cables calculated at an average temperature of 65 C. Cross Section (mm²) Impedance ( / km)

25 VOLTAGE DROP CALCULATION 1/ LV Side Voltage Drop : U LV 1/a) LV Single Phase Network : U LV = 2 L i (n (n + 1) / 2) Z U LV % = U / 230 (V) i (A) : rated current of one pole i.e. = P(VA) * q / 230 (V) with q : number of lamps per pole and P : power of one lamp L (km) : inter-distance length between each lighting pole, plus 5 meters cable to reach the pole. n : Number of poles on the side of the network transformer. Z ( / km) : LV cable impedance. 1/b) LV Three-phase Network : U LV = 3 L 3 (i* 3) (n 3 (n ) / 2) Z U LV % = U / 400 (V) i (A) : Rated current of one pole i.e. = P (VA) * q / 230 (V) with q : number of lamps per pole and P : power of one lamp. L 3 : Inter-distance between groups of three poles => for example l 3 = 3*L + 0,005. n 3 : Number of poles in group of three. 25

26 2/ MV Network Voltage Drop : U mv 2/a) TER or TED Type transformers (MV/LV) are regularly distributed in the network A-TER MM or TED MMX : U mv = L I (n(n+1)/2) Z U mv %= U mv / 3200 (V) I(A) : Intensity for a tranformer calculated on its nominal power in kva : I=P / 3200 (V). L (km) : Interdistance between each transformer. n : Number of transformer. Z (Ω / km) : MV cable impedance. B TER MT or TED MTT : U mv = 3 (3 * L) ( 3 * I) (n 3 (n 3 + 1) / 2) Z U mv %= U mv / 5500 (V) I (A) : Current of one transformer according to P (VA) calculated as I = P / 5500 (V). L (km) : Inter-distance length between each transformer. n3 : Number of transformers in group of 3. Z ( / km) : IHV cable impedance. C TER TT or TED TTT : U mv = 3 L I (n (n + 1) / 2) Z U mv %= U mv / 5500 (V) I (A) : Current of one transformer according to P(VA) calculated as : I = P / (5500 * 3). L (km) : Inter-distance length between each transformer. n : Number of transformers. Z ( / km) : MV cable impedance. 2/b) Deliver of power to a distance of L (km) three-phase network : U mv = 3 L I Z U mv % = U mv / 5500 (V) I (A) : Current of the network I = P / (5500* 3). Z ( / km) : MV cable impedance. L (km) : Distance between the supplier and the receiver. Please note : The power rating mentioned is the sum of the network transformers power rating. In the case of the network transformers load is reduced, we can use the sum of the power rating of the supplied lamps counting a coefficient of around 15 %. 26

27 Way of using the power supply range graph. These graphs help you to find quickly the right solution for the supply of a single load. The graph inputs are the distances of the load and its power. With these parameters, you obtain the voltage level to use and the wire section. Example : We have several receptors to supply at 3480 meters far. Their power are respectively 10,20,30 and 50 kva. You have to report on the graph the cross between the 10 kva line and the 3480 meters line. It is in the area for mono 3200V with a wire section of 6 mm². This is the best solution. You can also notice that it is under the non-continuous line for mono 950V 35mm² wire section. It means this solution is technically working but economically less profitable than medium voltage. It will be use only if we absolutely want to use low voltage. As for the 20 kva receptors, the only solution is 3200V wire section 6 mm². Then for 30 kva, we use 10 mm² as wire section and 16 mm² for the 50 kva receiver. Comment on the graphs. The drawing represent the technical limit for each kind of solution to respect a maximal voltage drop of %. All the area under the drawing respect this condition. The colored areas correspond to domain were the use af a solution is the more accurate. For distance shorter than 500m the graph are not valid. The non-continuous drawing represent the limit for a technically working solution but not profitable. 27

28 End of line single-phase loads 28

29 End of line three-phase loads 29

30 DETERMINATION OF THE 950 V CABLE SECTION 950 V single-phase network uniformally spread power : Compatible with a 2% voltage drop : Maximum input length in meters. Length (m) Power Rating Cross Section (kva) (mm²) Z (85 ) 3,19 1,919 1,24 0,8 0,595 I(A) 10 10, , , , , , , , Compatible with a 3% voltage drop : Maximum input length in meters. Power Rating (kva) Length (m) Cross Section (mm²) Z (85 ) 3,19 1,919 1,24 0,8 0,595 I(A) 10 10, , , , , , , , Compatible with a 4% voltage drop : Maximum input length in meters. Length (m) Power Rating Cross Section (kva) (mm²) Z (85 ) 3,19 1,919 1,24 0,8 0,595 I(A) 10 10, , , , , , , ,

31 950 V three-phase network uniformally spread power : Compatible with a 2% voltage drop : Maximum input length in meters. Power Rating (kva) Length (m) Cross Section (mm²) Z (85 ) 3,19 1,919 1,24 0,8 0,595 I (A) 10 6, , , , , , , , Compatible with a 3% voltage drop : Maximum input length in meters. Length (m) Power Rating Cross Section (kva) (mm²) Z (85 ) 3,19 1,919 1,24 0,8 0,595 I (A) 10 6, , , , , , , , Compatible with a 4% voltage drop : Maximum input length in meters. Length (m) Power Rating Cross Section (kva) (mm²) Z (85 ) 3,19 1,919 1,24 0,8 0,595 I (A) 10 6, , , , , , , ,

32 End of line 950 V single-phase network load : Compatible with a 3% voltage drop : Maximum input lengths in meters : Power Rating (kva) Length (m) Cross Section (mm²) Z (85 ) 3,19 1,919 1,24 0,8 0,595 I(A) 5 5, , , , , , , , , Compatible with a 4% voltage drop : Maximum input lengths in meters : Power Rating (kva) Compatible with a 5% voltage drop : Maximum input lengths in meters : Length (m) Cross Section (mm²) Z (85 ) 3,19 1,919 1,24 0,8 0,595 I(A) 5 5, , , , , , , , , Length (m) Power Rating Cross Section (kva) (mm²) Z (85 ) 3,19 1,919 1,24 0,8 0,595 I(A) 5 5, , , , , , , , ,

33 End of line 950 V three-phase network load : Compatible with a 3% voltage drop : Maximum input lengths in meters : Power Rating (kva) Length (m) Cross Section (mm²) Z (85 ) 3,19 1,919 1,24 0,8 0,595 I (A) 5 3, , , , , , , , , Compatible with a 4% voltage drop : Maximum input lengths in meters : Power Rating (kva) Compatible with a 5% voltage drop : Maximum input lengths in meters : Power Rating (kva) Length (m) Cross Section (mm²) Z (85 ) 3,19 1,919 1,24 0,8 0,595 I (A) 5 3, , , , , , , , , Length (m) Cross Section (mm²) Z (85 ) 3,19 1,919 1,24 0,8 0,595 I (A) 5 3, , , , , , , , ,

34 PERSONAL NOTES 34

35 PERSONAL NOTES 35

36 AUGIER IS CERTIFIED ISO 9001 SINCE 1995 With constant improvements, the manufacturer may alter information without prior warning