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ECODIAL 3.36

Nhấn vào đây để tải về
Báo tài liệu có sai sót
Nhắn tin cho tác giả
(Tài liệu chưa được thẩm định)
Nguồn: Schneider
Người gửi: Steven Hung
Ngày gửi: 14h:23' 20-04-2011
Dung lượng: 1.4 MB
Số lượt tải: 72
Số lượt thích: 0 người
1. INTRODUCTION
Ecodial 3.36 :

98 SE, Win 2000, XP



Included :
Contactors , Circuit breakers (Telemecanique),
Thermal relays, Soft starters, Variable speed drives, Capacitors

Calculation method : CENELEC (R0064-003)
Installation rules : IEC364, C15-100 (ed. 2003), BS7671
Calculation standards define the formulas that should be used to calculate short circuit currents.
IEC909 : method to calculate three phase short circuit currents in electrical installations

IEC363 : method to calculate three phase short circuit currents on ships

What is a calculation GUIDE ?
A simplified method that is usually accepted internationnally under certain conditions.

CENELEC guide R064-003 (as known as NFC15-500): method for calculating ALL short circuit currents (min, max, earth fault, single phase, three phase, …), voltage drops, cable short circuit withstand…

Guide often ignores transient phenomenon such as motor contribution, asymetric component, inrush when calculation short circuit levels.

Simplification is acceptable as product standards (IEC60947-2) take these transient phenomenons into consideration, for example :
an 50kA Icu breaker must be able to ‘make’ at least 110kA peak Icm
What are ‘calculation standards’ ?
IEC909, IEC363, ...

What are ‘installation rules’ ?
IEC60364, NFC 15-100, BS7671, CP5, AS3008, ...

Installation rules address all the issues relative to safety :
overload protection
minimum cable sizes
protection against direct and indirect contact
short circuit protection
These rules are usually all based on the same inital document (IEC60364), onto which each country usually includes local requirements (temperature, safety, cable derating…).
What is Ecodial ?
Ecodial is a low voltage network calculation tool.

It can calculate simple ‘arborescent’ type networks
no loops/ring feed systems

Ecodial calculates
cable cross section based on
upstream protection setting, maximum allowable voltage drop, protection against indirect contact,
short circuit currents according to :
type of short circuit, polarity of circuit and earthing method
sets protection devices based on
short circuit currents, expected loads, …
What Ecodial is not :
Ecodial is not :
A medium voltage design tool
A tool that can be used lightly : professional engineers must check verify and certify these results
The solution to all the possible design problems that one may encounter.

Ecodial cannot solve all the layouts
Several studies could be made...
Simplified network should be drawn...
General characteristics
- definition of the global parameters (voltage, earthing, …)

Drawing
- definition of the network layout

Definition of circuit characteristics
- definition of the terminal load, and all the cable lengths

Power sum
- calculation of the required power, and current in the distribution circuits

Calculation
- sizing of cable, calculation of short circuit currents, choice of equipment, …

Results
- printout of the input / output used for the calculations
The main steps of an Ecodial study

Un Ph-Ph (400V) : sets the LV network voltage. This value corresponds to a phase-phase voltage

Earthing arrangement (TNS) : sets the earthing arrangement at the transformer. This value can only be changed in a network after an LV/LV transformer, or from TNC to TNS.

Cascading (YES) : authorises Ecodial to use reinforced breaking capacity to choose downstream breakers. This can help reduce the cost of an installation.

Discrimination (standard) : displays the discrimination results and chooses breakers giving better discrimination results.

Smax (240mm²) : sets the maximum cable CSA that Ecodial can use when sizing cables (multiple cables in parallel can always be used though)

General characteristics
Calculation / General characteristics
CSA N / CSA Ph (1) : sets the minimum ratio between phase and neutral conductors. This is used to allow half neutrals (1/2) or require full neutrals (1).

Tolerance (5%) : Ecodial calculates the theoretical Phase CSA. Tolerance can be included to allow the choice of cable slightly smaller than the theoretical value.

Standard (IEC947-2) : Allows the user to choose a default product standard (IEC947-2 or IEC898) according to which the breaking capacity of the circuit breakers are given. If the standard is set to IEC898, Ecodial automatically chooses IEC947-2 if no IEC898 are available

Target power factor (0.96) : this is the value Ecodial will use to size the required capacitor bank. It corresponds to the power factor downstream of the transformer.

System frequency (50Hz) : enables users to choose products that are suitable for 60hz applications (capacitors, …).

Thermal stress compliance (No) : enables Ecodial to check out that cables chosen are in compliance with thermal stress under short circuit.
General characteristics
Calculation / General characteristics
Characterisrics spread down

One will be able to modify some of these characteristics afterwards. Ecodial will then ask whether the modified characteristic should be spread abroad down the electrical network or not. This function can be quite useful in case the user is looking quickly for the results of a variant of its own design







Spreading properties
Calculation
Sources : Transformer, Generator, Undefined,
(Bus coupler)
Busbar : Busbar, (interlock)

Feeders circuits

Loads : receiver, motor, lighting, variable speed drive

LV / LV transformers (isolating, step-up, step-down)

Miscellaneous : graphic links - project links

Drawings

Standard diagrams
Drawing the network - the symbol toolbox
Display / Symbol Toolbox
Drawing the network
Click on the symbol you wish to use:
the mouse pointer becomes this symbol

Click on the diagram where you wish to place the circuit
Ecodial verifies if this circuit can be placed there (if there is room, etc…)

Double- click on the circuit, and define :
Name
Characteristics (cable length, polarity, etc…)
Customise (cable  busbar trunking, circuit breaker  fuse, …)

Validate
Zoom : drag a box around the area to zoom into

Grid

Alf F3 = search for a particular circuit based on its name or ID

Circuit selection (multiple) : keep SHIFT button pressed while selecting multiple circuits, or draw a box around the circuits to select.

Moving circuits : drag and drop the selection

Copying circuits (including the characteristics)
select circuit to be copied
CTRL+C and then CTRL+V
Edit / Copy and then Edit / Paste

Enlarge busbars : select busbar, click on , enlarge bars.



Advanced editing
The first study

select circuit and (F4), or double-click on circuit
Name all the circuits :
Supply, Switchboard, Main Load, Main Motor, Main Lighting
Enter circuit parameters:
Main Load : 35m, 238A
Main motor : 39m, 110kW (mechanical),
Main Lighting :15m cable, 30m busbar, 20x150W Incandescent lights, 10 identical circuits

Useful tools
Network / Item lists …
faster input of circuit characteristics once the circuits are named.
Network / Logical check (F3)
Definition of circuit characteristics
Network / Circuit description
Automatically calculates the theoretical power of transformer and generator. (400kVA)

Automatically calculates the currents in the different branches of the circuits. (ex Total Switchboard feeders = 436.36A)

Ku and Ks coefficients can be used to optimise design.

Ecodial will recommend a transformer size.

Power sum should be run after every modification !
The Power Sum
Calculation / Power Sum
The Power Sum is not compulsory.

But then the user must manually define the currents in every circuits.
Advantage : quicker calculations :
Do not have to draw/enter all the circuits.
Enter only the circuits one wants to calculate, and expected current.
Disadvantage : results can be sometimes surprising !

POWER SUM IS RECOMMENDED IN BIG PROJECTS !
The Power Sum
Calculation / Power Sum
When single phases are connected to a three phase board, Ecodial can automatically suggest a phase distribution solution

The automatic distribution can be modified.

The logic applied is the following
Ecodial sorts the loads by decreasing intensity.
Starting from the highest load, Ecodial will place the loads onto the first phase until the sum of these loads is equal to 33% of the total load
Ecodial then tries to load the second phase until the sum of these loads reaches 50% of the remaining loads.
All the loads that remain are then allocated to the third phase.

This systems gives the best possible distribution in most cases. It is always possible to manually modify the result.

The upstream circuit is sized on the highest phase loading.
The Power Sum
Load distribution
Automatic mode
equipment is selected automatically.
No additional entry is required, Ecodial uses default values (installation method, cable type,…)

Manual mode
parameters can be defined by user, and then they are checked to see if they verify all the safety criteria.
An unsafe choice will not be allowed to be validated.

Equipment calculated
Circuit breakers (and fuses) and isolators
Contactors and relays
Cable, BTS, and busbar
The Calculation
Calculation / Calculate
Load current and breaking capacity identifies circuit breaker

Choice of circuit breaker sets thermal setting

Thermal setting defines minimum theoretical cable CSA

Verification of cable (Sp, Sn, Spe theoretic)
voltage drop
protection against indirect contact
short circuit currents

Sizing constraint (overload, voltage drop, user, …)
The Calculation
Calculation / Calculate
Busbar sizing :
For main busbar, size is defined by the circuit breaker protection which is defined by the nominal current of transformer (and not the sum of the load currents !)
For other busbar (sub DB) : sizing according to circuit breaker protection, which is defined by the load current.

Short circuit currents
Ik max : cold short circuit (copper is cold-low resistivity)
Ik min : warm short circuit (copper is warm - high resistivity)
Ik3 : three phase ‘bolted’ fault
Ik2 : phase - phase fault
Ik1 : phase - neutral fault
Earth fault : phase-earth fault
The Calculation
Calculation / Calculate
The Calculation
Resistivity values
ro : resitivity at 20 degrees Celcius (IEC909)
copper : 18,51
aluminium : 29,41
At different temperatures :
PVC
r1= 1,2x ro at 70 degrees
r2= 1,38x ro at 115 degrees (if S <= 300 mm²)
r2= 1,34x ro at 105 degrees (if S > 300 mm²
r3= 1,30x ro at 95 degrees (if S <= 300 mm²)
r3= 1,26x ro at 85 degrees (if S > 300 mm²)
PR
r1= 1,28x ro at 90 degrees
r2= 1,60x ro at 170 degrees
r3= 1,48x ro at 140 degrees
Linear reactance (non armoured cables)
multi core or single core in trefoil : l = 0,08
single core, flat touching : l = 0,09
single core, spaced : l = 0,13
The Calculation
Short circuit currents (values of resistivity to be used)

Ik3max, Ik2max and Ik1max : ro
Ik2min and Ik1min
for circuit protected by fuses : r2
for circuits protected by circuit breakers : r1
If (earth fault current)
TNC :
for circuit protected by fuses : r2
for circuits protected by circuit breakers : r1
Multicore, PE included
for circuit protected by fuses : r2
for circuits protected by circuit breakers : r1
PE separate
for circuit protected by fuses : r2
for circuits protected by circuit breakers : r1
Voltage drop : r1 : l = 0,13
The second study

Define new circuits :
Emergency DB feeder : 45 m , (I = ???)
Emergency DB
Emergency supply
Vital Load (36m, 135A)
Vital Motor (75m, 18,5 kW mechanical)

Run Power Sum
Transformer : 400 to 630 kVA
Generator : 160 kVA (only supplies Emergency board !)

Run Calculation

Modify the circuit

Under ‘Emergency’ supply, only the board under the ‘Emergency’ feeder is considered fed. All the other loads (those connected to the main DB are considered disconnected).
The ‘Normal’ source is sized on the sum of all the loads
The ‘Emergency’ source is sized ONLY on the loads on the ‘Emergency’ board.

For those feeders that can be fed by either the ‘Normal’ or the ‘Emergency’ supply, the worst case parameters are used to verify the selection and sizing of the equipment :
max 3 phase short circuit current
min earth fault current


Normal / Emergency supply #1
Normal / Emergency supply #2
Sources sizing :
Transformer T1 is sized for circuits 6 to 9 : 315kVA
Generator G5 is sized for circuits 8 to 9 : 100kVA
Short circuit level :
Maximum IK3maxis given by the transformer
Minimum earth fault current = minimum from the two
Power (kVA) : the nominal rating of the transformer. It is usually calculated and set in the power sum, nonetheless it can be manually set by the user here.
Type : choice between immersed or dry transformer
Earthing arrangement : a reminder of the earthing arrangement set in the general characteristics. Modifying the earthing arrangement here does not modify the earthing arrangement of all the downstream circuits.
Distributed neutral : networks have or not neutral conductor.
Un Ph-Ph : a reminder of the system voltage. If change, Ecodial will propose to spread down this property downstream.
Short circuit voltage : since version 3.36, Ecodial reads values of transformer’s reactance and resistance in tables 2A&2B of the UTE 15 106.
High Voltage short circuit power : short circuit level on the medium voltage side of the transformer. Enables Ecodial to read in tables 2A&2B to determine cross section area
Connection : the different windings of the MV/LV transformer (Delta-star; star-star; zig-zag)
HV operating time : time used to read in tables 2A&2B of the UTE 15 106 , the cross section area
Neutral & earth electrods resistance : use to calculate the imedance loop
Circuit description
Transformer

Circuit description
PE Cable Cross section area from transformer (2)

Immersed transformer
Dry transformer
Circuit description
Transformer (3)

Results :

R and X of MV network (using CENELEC R064-003 formulas)
XQ= 0,995 x ZQ RQ=0,1 x XQ


R and X of transformer : either read values onto tables given by CENELEC harmonised documents HD 538.1 / HD 428.1


Ib : rated current of the transformer (In)

Isc max (maximum short circuit current at the terminals of the transformer)


Copper losses (heat loss)


No load voltage coeficient Difference between IEC 909 and CENELEC R064-003
IEC 909 considers that Un is the no load phase phase voltage. CENELEC R064-003 considers that Un is the load voltage. It is required to introduce a corrective factor.
Circuit description
Transformer (4)
Dry transformer (NFC 52 115 - CENELEC HD 538.1 )




Immersed transformer (NFC 52 112 - CENELEC HD 428.1 )





Ecodial interpolates for missing Power values
Circuit description
Generators

Power (kVA) : the nominal rating of the transformer. It is usually calculated and set in the power sum, nonetheless it can be manually set by the user here.
Earthing arrangement : a reminder of the earthing arrangement set in the general characteristics. Modifying the earthing arrangement here will request spread down function.
Distributed neutral : networks have or not neutral conductor.
Un Ph-Ph : a reminder of the system voltage. If change, Ecodial will propose to spread down this property downstream.
X’o (%) : zero phase impedance, 6% by default or manufacturer value
X’d (%) : Transient reactance, 30% by default or manufacturer value
X’’ (%) : Subtransient reactance, 20% by default or manufacturer value
Neutral & earth electrods resistance : use to calculate the impedance loop

Ecodial uses the subtransient reactance to calculate the maximum short-circuit currents for networks supplied only by generator.
Circuit description
Any source

Un Ph-Ph : a reminder of the system voltage. If change, Ecodial will propose to spread down this property downstream.
I service connection (A) : Intensity of the connection, in other words the current rating of the upstream protection device (not drawn on the diagram).
Earthing arrangement : a reminder of the earthing arrangement set in the general characteristics. Modifying the earthing arrangement here will request spread down function.
Distributed neutral : networks have or not neutral conductor.
Neutral & earth electrods resistance : use to calculate the impedance loop
Ik3max (kA) : maximum prospective short circuit current at a the feeding point
Ik1min(kA) : minimum phase neutral prospective short circuit current. This value is used to calculate the ‘warm’ impedance of the Phase/Neutral loop.
If (A) : fault current
Short circuit power factor : power factor under short circuit
Initial dU (%) : existing voltage drop at the delivery point.
Energy supplier : choice between several public utilities (Ecodial adaptation requested)
Ecodial uses a specific algorithm that depends on the earthing system.
Circuit description
Any source (2)

Connection system drawing
Characteristics fields
Circuit description
Any source (3)
Why having such a complex algorithm?

The calculations made in Ecodial 3.2 were based on a number of simplifying assumptions that neglected the following problems:

The real constitution of a power supply network that can be a mixture of generators, transformers and cables of varying lengths.

The distance to the point where the neutral is created. For example, if a delta-star transformer is located just upstream, the neutral impedance is zero. On the other hand, if the cable impedance is high with respect to that of the transformer and the HV system, the neutral impedance will be close to that of the phases.

Upstream earthing location and method. This is particularly a problem TN systems, where the fault current could be confused with a single-phase short-circuit, while there is a very high probability of an equipotential link at the connection point.
Circuit description
Any source (4)
Factors Cmin and Cmax, along with the resistivities r0, r1 and r2 of the circuits, are used to distinguish between the maximum and minimum short-circuit current values.
However, what types of circuits are concerned, what are their lengths and what resisitivity values should be applied?
In this concern, UTE C 15 500 considers RQ and XQ, with RQ invariable with respect to temperature.

The ratio R/X of the different impedances.
Ecodial 3.3 offers the possibility of entering an additional value, the power factor under short-circuit conditions, that is applied for Ik3max and Ik1min. Of course, taking the same short-circuit power factor for Ik3 and Ik1 leads to an approximation in the calculation of the neutral and PE impedances.

A test is required to check for consistency between the values entered for Ik3max and Ik1min.
Ecodial 3.3 offers the possibility of checking Ik1min with respect to Ik3max. According to the characteristics (system earthing arrangement, distributed neutral, reduced neutral, etc.), incompatibilities will be corrected and the user will be asked to confirm certain assumptions.
Circuit description
Any source (5)
What to do when I have no information ?

When no information are known about the upstream network, the UTE (French standard) proposes to consider the following assuptions:

Earthing system : TT

HV/LV transformer 1000kVA, Usc 6%

15 meters distance, 240mm² aluminium single core cable, installed on to punched cable trays.

It is upto the designer to adapt these assumptions to match its project.
Circuit description
Capacitor

Power factor before compensation : value of the power factor calculated in the Power Sum (the Power Sum must be run to calculate a Capacitor bank)

Power of the Harmonic sources : In order to take into account the effect of harmonics on the capacitors, Ecodial needs the power of all the harmonic generating (non-linear) loads on the network. This value is used in conjunction with the transformer size to identify the type (Standard, H or SAH) of capacitor used by Ecodial.

Power (kvar) : Total power of the capacitor bank needed to attain the target power factor.

Type of compensation

Step : resolution of the automatic capacitor bank : ex 5x50kvar means the capacitor bank can go from 0 to 250kvar in steps of 50 kvar (controlled by the regulator)
Ib : current drawn by the capacitor bank (inclusive of possible harmonic currents and manufacturing tolerances)
Ih
L,w
C,w
Transformer
(PT)
Capacitor
(Q)
Harmonic current injection
Equivalent impedance of L-C circuit (resistances ignored)
Z= j.L.w / (1-L.C.w²)

Resonance when w²=(2.p.f)²=1/LC (Zmax induces to Voltage max)
order of resonance :

if order of resonance is close to harmonic current injection, filtering devices could be required.

Harmonic voltage created across the equivalent impedance of the transformer and capacitor, which causes circulating currents in the L-C loop, which can be a cause of nuisance tripping in transformer or capacitor protection devices.
Circuit description
Capacitor

Vh
Logic diagram for the selection of cable size and protection devices
short-circuit MVA at the
origin of the circuit
Isc
upstream or
downstream network
choice of
protective device
kVA to be supplied
short-circuit current
maximum load current
IB
short-circuit current-breaking
rating of C.B. or fuses
rated current of protective
device (C.B. or fuses)
verification of thermal
withstand requirements
verification of the
maximum length of
the circuit
confirmation of the cross-sectional area of the cabling,
and the choice of its electrical protection
determination of the
cross-sectional area
of the conductors
Iscb
In
cross-sectional area of
conductors of the circuit
choice of C.B
or fuses
conditions of
installations
TT scheme
IT or TN scheme
verification of the maximum
voltage drop
specifications
estimated power (kw)
The difference between a protection by fuses or C.B.

fuse
Iz = 1.31 In In < 10A
Iz = 1.21 In In > 10A < 25A
Iz = 1.10 In In > 25A
circuit-breaker

In or Ir
I`z =
Iz

K
conductor cross-section
I`z =
In or Ir

K
installation
conditions
K
1
.
K
2
.
K
3 =
K
apparent power to
convey
operational current IB
protective device
rated current
choice of protective device

short-circuit
power at origin
of circuit
short-circuit
current
protective device
breaking capacity
I
B
In or Ir
I
CC
bc
Checking maximal
voltage drop
configuration of choice of duct cross-
section and electrical protection
Checking maximum
duct length
IT or TN system
TT system
upstream or
downstrea m
network
choice of
protective device
determination of conductor
cross-section
Overall calculation algorithm
Estimated power
Calculation of service current iB
Choice of the protection device & its trip unit
Calculation of the cable size
Verification of the volatge drop
Calculation of the short circuit current
Choice of the breaking capacity
Verification of the cable stress
Discrimination
Cascading
Verification of the max length of IT & TN circuit
Confirmation of the cross section area
Circuit description
Circuit breaker (distribution)

Range : Product range from which the circuit breaker is to be chosen. If Ecodial cannot find a breaker in that range it will look for a breaker in a predefined range (function of the demand current)
Designation : name of circuit breaker
Trip unit / curve : name of the trip unit or curve of the circuit breaker
Nb of poles protected : polarity of the circuit breaker that is required.
Fire protection : this is a characteristic that will force an earth leakage device, and set it to ensure that a leakage current will not be able to cause a fire (threshold < 300mA)
Integrated with the protection device : certain RCDs are integrated (NS Vigi, …) and certain are separated (RH***). The user can choose the type of RCD required. By default, Ecodial looks for integrated RCDs, and then separated RCDs if unsuccessful.
Class : (A / AC ) defines the sensitivity of the RCD to continuous and pulsed DC signals.
Earth leakage protection device : name of the device ensuring the function of RCD.
Earth leakage protection : if earth leakage protection (RCD) is required (by user, or for a particular application, switch this characteristic to YES).

Sensitivity (mA) : pickup current of the RCD device
Delay (ms) : time delay before disconnection under earth fault conditions
I thermal setting (A) : Thermal setting of the circuit breaker. This value is set to be greater or equal to the demand current, and is used to size the cable.
I magnetic setting (A) : magnetic setting of the circuit breaker. This setting s made to ensure protection against indirect contact in TN, and to ensure correct motor starting based on start-up currents.
Frame rating (A) : maximum rating of the circuit breaker frame
Trip unit rating (A) : maximum setting of the trip unit.
Im/Isd : position of the magnetic adjustment on the trip unit
Ir : position of the thermal adjustment on the trip unit
Io : position of the thermal adjustment on the trip unit
Motor mechanism : breakers must be able to be fixed with a motor mechanism
Circuit description
Circuit breaker (distribution) (2)
Cascading requested :
YES : circuit breaker is chosen using cascading with the upstream device (only the device directly upstream)
NO : circuit breaker is chosen based on its stand-alone breaking capacity.

Discrimination requested :
YES : circuit breakers that have better discrimination potential are selected instead of normal circuit breakers

Installation : Fixed breakers or withdrawable breakers
Circuit description
Circuit breaker (distribution) (3)

Circuit description
Circuit breaker (motor)

Range : see previous
Designation : see previous
Trip unit / curve : see previous
Contactor : name of contactor to be used according to the co-ordination tables
Thermal protection : name of thermal overload (if needed) according to co-ordination tables.
Fire protection :see previous with the added safety that the tripping time is delayed by at least 60ms to ensure there is no nuisance tripping on start-up.
Soft starter : name of soft starter (if needed) according to co-ordination tables.
Earth leakage protection : see previous.
Number of poles protected : always 3P3T, as Ecodial does not cover single phase motors
I thermal setting (A) : Thermal setting of the circuit breaker. This value is set to be greater or equal to the demand current, and is used to size the cable.
I magnetic setting (A) : magnetic setting of the circuit breaker. This setting s made to ensure protection against indirect contact in TN, and to ensure correct motor starting based on start-up currents.
Frame rating (A) : maximum rating of the circuit breaker frame
Trip unit rating (A) : maximum setting of the trip unit.
Im/Isd : position of the magnetic adjustment on the trip unit
Ir : position of the thermal adjustment on the trip unit
Io : position of the thermal adjustment on the trip unit
Motor mechanism : breakers must be able to be fixed with a motor mechanism
Cascading requested :
YES : circuit breaker is chosen using cascading with the upstream device (only the device directly upstream)
NO : circuit breaker is chosen based on its stand-alone breaking capacity.
Discrimination requested :
YES : circuit breakers that have better discrimination potential are selected instead of normal circuit breakers
Installation : Fixed breakers or withdrawable breakers
Circuit description
Circuit breaker (motor) (2)

Circuit description
Load (1)

Number of identical circuits : instead of drawing multiple feeders having EXACTLY the same characteristic, just draw one !

Ib : demand current of the load (calculated from the power and polarity)

Circuit polarity : polarity of the load

Earthing arrangement : see previous

Power (kVA) : demand power (calculated from the current and the polarity)

Power factor : power factor of the load (.8 is default value)

Ph/earth fault max turn off time :
User may have the ability to force to 5s the tripping time of the breaker, but in TNC/TNS.


Circuit description
Load (2)

Load type & environment:
Load type : Ecodial offers you a variety of choices: standard, corresponding to the general case, or certain special cases: heating floor – Instrumentation/measurement – Public lighting – luminous signs – computers
Environment : various choices are pre-selected: standard, corresponding to the general case, or certain special cases.

Depending of both characteristics Ecodial will force RCD protection and in some cases will propose a SI type from the Multi 9 range.
That’s specially the case when the load is considered as mobile : terminal load is fed through a power socket (special earth leakage conditions are then applicable : 30mA and Instantaneous protection is required)

Circuit description
Motor

Type of starting : for Direct on Line or Soft Starting applications
Mechanical power (kW) : rated mechanical power of motor
Motor efficiency : ratio between mechanical and electrical power (in kW)
Ib (A) : full load current of motor
Circuit polarity (always 3P)
Power factor : full load power factor of the motor
Earthing arrangement : see previous
Power (kW) : demand power (calculated from the efficiency)
Type of co-ordination : Type 1 or Type 2
Number of identical circuits : see previous
Starting class : Standard / Long
Id/In : ratio between inrush and nominal current .Start-up current sets the magnetic setting of the breaker
Ph/earth fault max turn off time : see previous
Type1 and Type2 co-ordination
IEC60947-4
Association between the protection (thermal and magnetic) and control devices.
Defines safety and maintenance levels of the association (IEC60947-4).
These associations are verified/proven through testing at levels defined in the standards (corresponding to extreme conditions on the equipment)

Type 1 : damage is accepted on the contactor and the thermal relay under the two following conditions :
there is no risk for the operator
other elements must not be damaged
more maintenance required, poor continuity of service, cheaper equipment

Type 2 : it is acceptable for the main contacts to solder ‘lightly’ : they can be easily separated...
little maintenance required, continuity of service improved, more expensive equipment
Circuit description
Lighting
Number of identical circuits
Lighting Source : type of lamp
Individual lamp power :
Number of lamps per light : for each lighting point there can be several lamps
Nb of lights (A) : total number of lamps on the Canalis lighting line
Ib : full load current at the origin of the Canalis lighting distribution
Ballast power : for lamps using ballasts (fluo tubes, …)
Circuit polarity
Earthing arrangement
Power (kW) : total demand power (calculated)
Power factor : individual lamp’ s power factor
Ph/earth fault max turn off time : see previous
Environment : see previous
Circuit description
Socket
Number of identical circuits
Ib : load current of the total distributed sockets
Circuit polarity
Earthing arrangement
Power (kW) : total demand power (calculated)
Power factor : total expexted power factor
Ph/earth fault max turn off time : see previous
Load type & environment : see previous
Circuit description
Variable Speed Drive
Reference : name of VSD
VSD IP : level of dust & water protection level (will define VSD type range)
Permitted transient torque (A) : starting torque (High or standard)
This information is directly linked to the type of application (lift, roof top fan, liquid pump, etc…)
Note : a VSD can work either with a standard or high transient torque (especially for motors over 15kW). Electrical characteristics fluctuates
Transient overtorque value (%) : value of permitted transient overtorque
Heat power consumed : VSD heat loss (value from VSD data base)
Nominal power of the VSD (kW) : characteristic of VSD
Form factor (K): ratio between total RMS and 50Hz signal (characteristic of VSD)
Ib consumed by the VSD : current drawn by VSD (including losses)
Called current : inrush current
Maximum deliverable nominal current : permanent Is output current
Maximum transient current for 60s/10min : output current Is maximum 60s (characteristic of VSD)
Earthing arrangement
Circuit polarity
Circuit description
Variable Speed Drive (2)
VSD selected based on
full load current of the motor
permitted transient torque (A) = type of starting : standard or high torque
VSD Ip ratings ( if low IP, ATV38 is selected)
Voltage range : ATV 68/38 have various characteristics depending of voltage

Active power supplied by VSD:
kWe= kWm / r (r motor efficiency)
Heat dissipation power by VSD
Pl (function of the VSD selected)
Power drawn by VSD
power factor = 1
kVA = kW = kWe + Pl
Ib consumed by the VSD
k = form factor linked to presence of harmonics (function of VSD)
Ib = kVA / (1,732 x V) x k

Circuit description
Cable
Length : length of the cable (Short circuit and voltage drop calculations)
Installation method : code for the type of installation. Defines the standard derating factors and the type of conductors used.
Insulation : sets the insulation material of the cable (impedance calculation)
Type of conductor : output from the Installation method, not an input !
Neutral loaded : source of derating on 3P+N networks
Conductor arrangement : calculation of the linear reactance of the cable
Type of PE : influences the type of cables selected by Ecodial
Number of additional circuits : cable derating
Number of layers : cable derating
K user : additional cable derating (over and above the standards)
Ambient temperature : cable derating
Delta U max on circuit (%) : maximum voltage drop allowed on the cable
Reference : name of cable

Circuit description
Cable (2)
Nb Ph conductor : calculation result
CSA Ph conductor : calculation result
Nb N conductor : calculation result
CSA N conductor : calculation result
Nb PE conductor : calculation result
CSA PE conductor : calculation result
Phase metal : cable characteristic (input)
Neutral metal : cable characteristic (input)
PE metal : cable characteristic (input)
Safety voltage : 50V or 25V

Ecodial and the earthing schemes
Implementing protection against indirect contact
TT
Earth fault current (leakage) calculated using the impedance of the source and earth electrodes, and the Phase-Earth conductor impedance
Standards require an RCD device on the main incomer
 the earth and source electrodes must not be interconnected !
TN
Earth fault current calculated using the Phase-Earth conductor impedance
Protection against indirect contact ensured by setting the magnetic under the Earth fault current
Trip units can be changed to ensure accurate magnetic threshold is used
RCDs can be implemented
IT (2nd fault)
identical calculations as for the TN system
Earth fault current is calculated assuming both fault occur at the same point. This ensures ‘worse case scenario’ as if the second fault appears further away, the real fault current on the 2nd fault would be greater than the calculated fault current corresponding to the 2nd fault location, and ensuring tripping by the 2nd fault location protection device.
Calculation rules
Phase CSA


Theoretical Phase CSA : calculated by a formula, where (IEC 60364-5-523-B):
K is the total derating (temperature laying method, cables in parallel, …)
Irth : is the thermal setting of the upstream breaker
m and a : parameters defined by the laying method and the type of cable (metal, insulator) andthe number of loaded conductors in the circuit)

Choice of Phase conductor
based on cable database supplied
based on theoretical phase CSA and tolerance
based on installation rules (ex TNC Smini = 10mm²)
based on limits implied in the standards (ex Smini for multicore conductors on perforated tray = 25mm²)
based on maximum phase CSA allowed

Voltage drop is calculated on this cable using demand current
CSA could be increased
Calculation rules
Neutral CSA
Theoretical calculation made by Ecodial
minimum theoretical CSA equal Ph or Ph/2

Warning : the Neutral, as any cable, should be sized according to the upstream protection setting (this is to ensure safety)
With 4p4t CB, the neutral can be of the same CSA of the Phase
With 4p3t 1/2N, the neutral can be half
With 3p devices (Neutral not protected), there is an unknown, as there is no direct protection on the neutral…

Phase unbalance can lead (worse case scenario) to a phase current equal to neutral current, so Neutral should be at least equal to Phase

Triplen Harmonics see specific rules
Calculation rules
Neutral CSA
Recommended actions :
use half neutrals
when there is a 4p3t N/2 circuit breaker protecting the circuit,
and if there is no possibility of excessive phase unbalance and/or triplen harmonic loading on the circuit.
Note : 3p3t are acceptable solutions, but 4p3t N/2 offer more safety under unexpected conditions

use full neutrals
when there is a 4p4t circuit breaker protecting the circuit
and if there is a possibility of excessive phase unbalance, or limited triplen harmonic (max allowed = 33% triplen in the RMS)
Note : 3p3t are acceptable solutions, but 4p4t offer more safety under unexpected conditions

use double neutrals
with 3p3t circuit breakers
when there is a high risk of excessive triplen harmonic
Calculation rules
PE CSA
Automatic minimum PE :
if Ph  16mm², PE = Ph x kph/kpe
if Ph  35 mm², PE = 16mm² x kph/kpe
if Ph > 35 mm², PE = Ph/2 x kph/kpe
where kph and kpe function of the type of phase and earth conductor (metal, insulation, single/multi core, …)
in TT, max PE = 35mm²

Theoretical minimum PE : the theoretical minimum PE cross section should only verify the I²t < k²S² condition, as very little current is ever expected to flow on the PE (as it is an equipotential link). This condition usually implies small PE cross sections (+/- 4mm² in TN and 1mm² in TT). Using such small cables has two bad consequences :
reducing Earth fault current (due to higher loop impedance), which could require the use of earth fault protection devices or lowering the magnetic thresholds to non efficient levels (motor starting and discrimination problems)
creating a higher voltage differential on the PE due to natural leakage currents
 Ecodial chooses automatically the CSA given above, but allows smaller cables to be selected by the user.
Network
General characteristics
TNS
400V
Transformer
800kVA transformer
Incomer cable length = 0
Load
3P+N
160A
Installation method 14,touching, multicore, trefoil
THDI<15%


Calculate the network with :
Load cable length =30m, 100m, 140m, 170m
Info needed : Irm, If, Sph, Spe, DeltaU, CB, Sizing criteria
Calculation examples
the effect of long cables
Calculation examples
the effect of long cables
Cable sized on upstream thermal setting
Cable sized on voltage drop
Setting of trip unit to cater for low earth fault current
(protection against indirect contact)To ensure disconnection in sufficient time, Ecodial verifies that the earth fault current is higher than the magnetic setting of the breaker (including tolerance).
Trip units can be changed to ensure this :
C curve to B curve (Multi9 breaker)
TM to STR (NS breaker)
Cable size can be increased
If no solution is found Ecodial interrupts the calculation requesting the user to manually place an RCD on the circuit breaker to ensure disconnection, and therefore protection against indirect contact.
Non-uniformly distributed load
the Icc and DeltaU can be calculated at each tap-off point, or for worst case scenario (Icc at source)
Calculation method to be used for distribution systems having loads that vary substantially in power and location.

Uniformly distributed load
the Icc is calculated at the beginning of BTS.
The voltage drop is estimated as a function of the number of tap-offs
Calculation adapted for distribution systems having evenly distributed loads (in power and location)
Calculation examples
Prefabricated busbar trunking
Uniformly and Non-uniformly distributed load.
800kVA
100A tapoffs
D=5,10,15,20,25
Total length 30m
Info needed :
Icc, deltaU per tap/off.
Calculation examples
Prefabricated busbar trunking (2)
Ku : usage coefficient
applicable to a CIRCUIT
% full load current when load is running
example :
motor +/- 80%
Light 100%

Ks : diversity coefficient
applicable to a DISTRIBUTION BOARD
chance of all feeders drawing maximum load at any given time
relative to the number of feeders on DB.
See Electrical Installation Guide
The Power sum, KS & Ku
Diversity and usage coefficients
The Power sum, KS & Ku#2
Ib is the maximum current potentially consumed by the load.
Therefore, Ecodial makes sure to take the worst case if considering the maximum Ib.
Ib will size the frame and the overload protection of the protective device.
Consequently Ecodial does not consider the Ku input for the load.
The Power sum, KS & Ku#3
Ku is a user coefficient.
If the user knows is equipment load will be only 80% of the nominal current, he should input 0.8. These kind of assumptions are quite common for motors.
Ku is not used to size the macro component. He is taken into account to size the upstream circuits
The Power sum, KS & Ku#4
The Power sum, KS & Ku#5
154.6
36.24
>
The Power sum, KS & Ku#6
154.6
The Power sum, KS & Ku#7
154.64
240.86
110.94
The Power sum, KS & Ku#8
154.64
240.86
110.94
S
The Power sum, KS & Ku#9
The Power sum, KS & Ku#10
The Power sum, KS & Ku#11
Apartment blocks :
Consumers 4 9 14 19 24 29 34 39 49
Ks 1 .78 .63 .53 .49 .46 .44 .42 .41

Distribution Boards (IEC439) :
Circuits 3 5 9 10+
Ks .9 .8 .7 .6

Circuits (Ks or Ku ?):
Lighting 1
Heating, air conditioning 1
Socket outlet circuit .1 to .2 (higher in industry)
Lifts/hoists 1 / .75 / .6
The Power sum, KS & Ku#12
Problem with Ku and Ks
Responsibility of the user
Personal experience
Knowledge of installation
Database of existing installations

Advantage of Ku and Ks
more cost effective installation
not oversized
Example
total installed power : 144kVA
maximum expected demand : 80 kVA
The Power sum, KS & Ku#13
Circuit breaker and busbar selection
Discrimation and cascading tables
Tripping curves
Guides and tools
Maximum number of circuits in a project : 200
Maximum number of copied circuits : 50
Maximum number of transformers : 4
Network calculation limitation
Short circuit limitation : why ?
Installation of current limiting circuit breakers offers several advantages
current limiting circuit breakers considerably reduce the undesirable effects of short-circuit currents in an installation.
cable heating is reduced hence longer cable life.
electrodynamic forces reduced, thus electric contacts less likely to be deformed or broken.
measuring equipment situated near an electric circuit less affected
the cascading technique offers substantial savings on equipment, enclosures and design by using lower rated devices downstream.
Principle of limitation
prospective current
limited current
arc voltage
network voltage
U arc
i u
I limited
t
Limitation : how
The limiter block operates in a similar manner to the main poles of the circuit breaker but is not linked mechanically to the main poles or to the tripping mechanism of the circuit breaker.
This allows the limiter contacts to re-close after fault interruption. Isolation is then provided by the circuit breaker contacts.
I
I
Fr
Fm
I
I
Fm
What it is limitation : tables to use for applications
circuit breaker limitation capability : the limitation capability of a circuit breaker is that characteristic whereby only a current less than the prospective fault current is allowed to flow under short-circuit conditions.
Definition : discrimination
discrimination (selectivity), is the coordination of automatic protective devices in such a manner that a fault appearing at a given point in a network is cleared by the protective device installed immediately upstream of the fault, and by that device alone.
why is discrimination useful ? Discrimination contributes to continuity of service, a necessity in many industrial, commercial or institutional installations.
Full or restricted discrimination
Full discrimination
Restricted discrimination
Definition : cascading
cascading is the use of the current limiting capacity of circuit breakers to permit installation of lower rated and therefore lower cost downstream circuit breakers.

the principle of cascading has been recognised by the IEC 364-434.3 standard

cascading can only be checked by laboratory tests and the possible combinations can be specified only by the circuit breaker manufacturer.

comments : the upstream CB acts as a barrier against short-circuit currents. They thus allow circuit breakers of lower breaking capacity than the prospective short-circuit current at their point of installation to operate under the stress conditions of normal breaking.
Harmonics : introduction of specific cable sizing
Triplen harmonics :
Origin : harmonics are created by non linear loads that absorb current in a form a discrete peaks . Harmonics are generated by DC adpater, fluorescent tubes, wheastone led circuit..
(3rd, 9th, …) add up on the neutral. Therefore, if the phase is ONLY 3rd harmonics, neutral current = 3x phase current. In reality, the neutral current will usually be less than 1.7-1.8 times the phase current, example ;
Irms (phase) = (I1, I3 (80%), I5(45%), I7(12%)) = 1.36x I1
Irms (neutral) = 3x I3 = 2.4x I1 = 1.76 Irms (phase)
The NFC15-100 has introduced in 2003, rules for the calculation of CSA of conductors.
It defines the THDI, harmonics rate in current as


Typical values of the THDI and impact onto the LV installation
 a value lower than 15% is considered as normal. No running disturbance is to be feared. Neutral conductor is not loaded.
 Between 15 % and 33%, one considers harmonics polution as medium. There is a risque of over heated cables, that induces oversizing of cables from sources. Neutral is loaded.
Ocer 33%, one consoders harmonics polution to be severe. Runing disturbances will occur. It must be analysed accurately and some specific tripping unit might be required.
Harmonics : cable sizing
THDI <= 15%
15%33%Single core cable
multicore cable,
CSAph<16mm² (Co), 25mm² (Al)
multicore cable,
CSAph >16mm² (Co), 25mm² (Al)
single cable,
CSAph >16mm² (Co), 25mm² (Al)
CS N <= CSA Ph
CS N <= CSA Ph
CS N = CSA Ph
CS N = CSA Ph
CS N = CSA Ph
k=.84
CS N = CSA Ph
Neutral determine Ph
Ib N = 1.45 Ib Ph
k=.84
CS N = 1/2 CSA Ph
Neutral protected
CS N = CSA Ph
k=.84
CS N = CSA Ph
Neutral determine Ph
Ib N = 1.45 Ib Ph
k=.84
CS N = 1/2 CSA Ph
Neutral protected
CS N = CSA Ph
k=.84
CS N > CSA Ph
Neutral determine Ph
Ib N = 1.45 Ib Ph
k=.84
Installation IEC 364 : even IEC 364 has been fully updated yet, Schneider Electric is stating that one
 
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