Specimen of Complete Spedfication

TITLE;

Section Terminal capacitor Bank circuit for Railway Electrified Traction

(Reverse feeding of Leading KVAR from Sectioning post)

Background of the invention

Through this modified capacitor bank circuit, the leading KVAR which required for improve the power factor can be distributed evenly . Also this circuit improves the voltage at terminal end of the circuit, hence power can be saved to certain percentage.

PRIOR ART

In Railways, 25 Kv traction, due to the Inductive Reactance Property of Some type of running Loco Loads, the current flow through the traction lagging behind the apllied EMF. Hence the Power factor value got lowered as less than 0.8.

To improve this power factor value ,the capacitor Bank which gives required amount of leading KVAR connected at the supply feeding end of Traction supplying station. This equivalent value of leading KVAR counter act with the lagging KVAR and improve the value of power factor as nearly 0.99.

Normally this capacitor Bank should be fixed at running Load ends only. But due to non feasible circumstance and for the safety purpose, the capacitor Bank has placed at supply feeding end of TSS.

But due to the presence of inductive reactive property of traction line, it has some lagging impedance and connected in series with the load. So that the total impedance of lagging of running loco varying from the TSS.

So the supplied leading KVAR from supply feeding end not evenly distributed to the running loco with respect to the length of the traction. When ever loco is at far end of (terminal) TSS it get lowered amount of leading KVAR than at near the TSS due to the leading KVAR counteract with the inductive reactive component of series impedance of traction line. Hence the Loco get appropriate amount of leading KVAR only at near the TSS.

Also due to the presence of series lagging impedance of traction line, certain percentage of voltage is dropped across it according to the load current. This voltage drop decreases the input voltage of running loco which is at terminal end. Hence the efficiency of utilization of power for the input also decreased.

Since Some type of Locos that they have inductive reactance, causes the current flow through the circuit lags 6 angle behind the applied EMF as
IL = IM Sin( ωt-θ)

Where IM sm(ωt=i the instantaneous current flow due to applied EMF across resistive component, (active component).

The current flow through the Inductance containing circuit IL lags 0 behind the EMF E. Hence the horizontal component of apparent power E. IL is equal to the active component as E. ILωθ

Hence by making θ =0 only the current will be in phase with the voltage and hence the power factor will be improved

The capacitor current Ic counter react with lagging current of inductive circuit as IL Sin 9
IL Sin θ = IC

In the parallogram of phasar diagram AB = Ic = CD = IL= SinG

Hence 9 approaching '0' value the value of Cos9 tends to 1 (between 0.9 to 1)

Hence the value of power factor improved.

The above said improvement of power factor is true only when the running load is approaching the TSS.

When the running inductive load is moving away from the TSS, the additional impedance of traction line having inductive reactance also connected in series with the running load.

Hence as the load moving away from or approaching to the TSS the value of line series impedance increasing or decreasing respectively.

Since he traction wire has the nature of inductive reactance for running load and the impedance due to this inductance is 0.24 Ω/km for double line and 0.48 Ω/km for single line.

In TSS, there are two parallel traction circuits distributed from the supplying end of TSS. Each traction circuit has the distance of length approximately 25 km to 30 km. so the net impedance for this length is = 30 x 0.24 = 7.2 Ω

Hence there are two types of losses of leading KVAR due to this line series impedance as follows:

If we connecting capacitor bank at the supply feed end of TSS in parallel to that and if the running load being at the terminal end of TSS

Then more than 1/4th of leading KVAR first counter act with the perpendicular reactive component of the lagging power of traction line due to the dropped voltage I.

ZLS = V LS only remaining 3/4th of the leading KVAR reached to terminal end running load and interact with reactive component of the running load Let the dropped power across the length of section of TSS is I2 ZLs Then the perpendicular reactive component of it = I2. ZLS Sin θ

According the calculation, this is equal to the 1/4th of leading KVAR in opposite direction Hence1/2V.Ic = I0.ZLs Sine θ

Hence 1/4th the leading KVAR supplied from the TSS lost by counter reactive in this lagging component of line series impedance ZLs.

Hence only 3/4th of leading KVAR reaches to the running loco where at the terminal end of section of TSS. Hence the power efficiency for this loco will be reduced.

To eliminate these above draw backs and to get constant power factor with respect to the length of the traction, and to improve the efficiency of power transmission the capacitor bank which gives required leading KVAR should be placed at Sectioning post (SP) of both terminal ends of the sections of the TSS.

Since according to the results get from model experiments it shown that the performance of terminal bank capacitor is more effective than even the capacitor bank fixed at individual running load ends. Also the Revolution Per Minute (RPM) of the load increased to certain percentage. Hence the power also can be saved to certain percentage.

Since terminal bank capacitor connected to reverse direction to feeding end of power supply of TSS, So it supplies the leading KVAR evenly as well as partially nullify the series Inductive reactance of the traction line and hence at terminal end of TSS voltage has also been improved. Since due to the positive and negative reactance properties of the LCR circuit, there will be improvement of voltage obtained.

Also due to this reduced Inductive reactance of traction of line, the induced voltage in copper conductor of signal and telecomm cables which laid parallel to the line may also decreased. Hence this is third advantage of terminal feeding capacitor bank of TSS.

The fourth advantage of the STCRB is 25KV supply can be extended from one TSS to nibhour section of TSS in case of that TSS in failure condition, with minimum line loss and unaffected power factor due to the itervening of Section Terminal Capacitar Bank provided at middle and terminal part SPs of extended section.

Section Terminal capacitor Bank Circuit (STCRB)

Construciton;

As per Figure N o 1
Normally one TSS having two supplying sections from both end of it. The capacitor bank which giving required KVAR is placed commonly at supply feeding end of the 110/25 kv and parallel to that.

Then from the parallel bank capacitor the leading KVAR Ic x Kv is distributed (2400 KVAR) towards both the end supplying section.

Instead of placed at supply feeding end, the capacitor bank should be placed at Sectioning post (SP) of terminal ends of both sections of a TSS as shown in the fig. which of each one giving 1/2 of the required leading KVAR.

i.e. half of the required calculated leading KVAR capacitor Bank provided at one SP of the terminal of TSS section and another half of leading capacitor Bank provided at another SP of the end of the TSS section. Even though these two STCRB's put at terminal end of supplying station by increasing the KVAR of it will carry out exact performance just like the original activity of the some equivalent value of capacitor Bank provided at supply feeding end of TSS. This explained later.

Normally the Leading current Ic from supply feeding end capacitor Bank SFCRB only counter act with the lagging current II of the running load and not counter act with the series impedance of traction line. Since SFCRB is excactly connected parallel to the impedance ZLS of traction line and running load which are connected in series. Hence it is only just a parallel circuit of capacitance and inductance.

Hence by difference between II and Ic, it improved only the power factor and not improve the input voltage of terminal running load.

But the Section Terminal Capacitor Bank is the combination of series parallel circuit of two inductances and one capacitance, it is in a manner that the inductive reactive impedance ZLs of traction line connected in series with the STCRB and as well as the STCRB connected parallel to the running load ZR of the section

Hence it is doing double actions as
(1) Giving lossless KVAR to the running loads of the section
(2) By neutralizing the line series impedance of traction line it improves the input Voltage of the running load at terminal end of the section of TSS.
(I) Loss less Feeding of Leading KVAR bySection Terminal capacitor Bank
(STCRB)

As per Figure No 2
When the capacitor Bank placed at SP of terminal end of TSS section, it will not face the lagging reactive component of dropped power across ZLS as said former. Since the terminal feeding capacitor Bank feeds the leading KVAR reverse to the direction of TSS supply. Hence when a load running along traction of a section of TSS it is passed between two series impedance of traction line of ZLs1 & ZLs2 the series impedance ZLs1 is connected in series to the source of TSS. The remaining line series impedance ZLs2 connected in series with the capacitor Bank acts just like series reactor.

Hence there will be no need of series reactor arrangement for the terminal feeding capacitor Bank STCRB.

Since the line series impedance is inductive for capacitor current Ic and it reduces capacitive reactance of STCRB for only a very small portion.

As per Figure No 3
ZC1 = ZC - ZLS where ZLS<< ZC hence ZC1 = ZC

Hence the maximum voltage will be dropped across the terminal Bank capacitor not across the line series impedance.

This line series impedance is always safety for the capacitor Bank.
So the terminal feeding capacitor Bank feeds loss less leading KVAR to the running load available at terminal end even as the running load moving away from the terminal capacitor Bank.

Also even though two leads running in a section of TSS, the leading KVAR reached to them without loss. Since the reactive component of inductive of series impedance of traction line between them is neutralized by the terminal capacitor Bank.

(II) Terminal Feeding Capacitor Bank make Improvement of Input Voltage at terminal point running loads of section TSS (Improvement of Voltage)

The terminal feeding capacitor Bank 'C connected in a manner such that in series with the inductive impedance of traction line and connected parallel to the running loads.

As per Figure No 4

If we taking the circuit containing series impedance of traction line only
The current flow through the capacitor Bank 'C nullify the dropped line voltage equal to Ic . ZLs

Hence as per above diagram
Vo =IC(ZC-ZLS) Vo =IC(XC-ZLS) Vo = Ic Xc - IcZ:LS
(1)
ICXC = VO+ICZLS
since Zc = [(Xc f But R=0 Hence Zc = Xc and since
Zc / Zls , Zls get negative sign.
or VC = Vo + IC ZLS
= Vo + dropped voltage across the line of traction due to Ic = Vo+ VcLs (2)
Vc is the Output voltage at terminal end of the TSS section which is across the STCRB.

This is the input vokltage for the running load at terminal end. Hence the running load get additional improvement of voltage as V CLS = Ic -ZLS

Input voltage Vg of Running Load at Terminal end when Section Terminal
Capacitor Bank (STCRB) added

The approximate input voltage across running load VRI = (VIN - VL) + Vc at no running load condition

As per Figure No 5
The voltage across the line series impedance due to section terminal capacitor bank current Ic without running load is VcLS = Ic Zls Let the voltage across the line series impedance due to running load current II, withoutterminal end capacitor Bank be VLLS = II ZLS

Then net voltadge dropped across the line series impedance Zls due to both capacitor current Ic and running load current II, VLS = VLLS – VCLS = ILZLS -ICZLS = ZL(IL -IC )

Hence the input voltage across running load with section Terminal Capacitor Bank VR = VO-VLS

Where Vo = 25KV is the output voltage of transformer secondary = VO-ZL(IL -IC )
Hence this Ic . Zls gives the improvement of input voltage of running load at terminal end and it remains unchanged depending upon the running load conditions.

a Ic = Terminal capacitor current a Zls = Total Traction line series impedance between terminal end to TSS supply

Hence as long as the capacitance increasing (leading KVAR) the improvement voltage will be increased.

Approximate calculation of improvement of voltage

As per Figure No 6

Let at no running load condition

Xc = Capacitive Reactance of STCRB
ZLs = Series impedance of traction line
Zo = Leakage reactance Impedance of secondary winding of

25 KV /110 KV transformer at TSS then as per equation the terminal input voltage Vc=Vi„ + Ic(ZLs + Zo) (Where Ic = Vi„/Zc) then improvement of voltage
Vc-Vin = Ic(ZLS + Z0)

The value of total impedance of traction line Zls = 7.2 < 70° Ω / 30 km for a section of TSS between feeding end to terminal end the source impedance of secondary coil of the 110 kv / 25 kv is Zo = 7.398 /85° Ω.

Hence total impedance which the capacitor current Ic passing through it is Ztotal = Zl + Zo= 7.2 Ω +7.398 Ω = 14.598 Ω

Let the capacitor current Ic due to one end terminal Bank capacitor of TSS section be 100 Amps.

Then the improvement of voltage at terminal end VLS = IC(ZLS + ZO) = ICXZL total = Icx 15Ω = 100 X 15 Ω = 1500 volts = 1.5 kv//

For two sections of TSS source impedance due to leakage reactance of secondary coil of the 110/ 25 kv transformer is common for two circuits.

As per Figure No 7
Hence for section 1 improvement of voltage across one terminal end of TSS section
= Ici (ZLS) + ZO (Ici + hi) improvement of voltage across another terminal end of TSS section = Ici (ZLS2) + ZO(ICI + IC2).

Brief discriptiopn of Drawings

As per parts of figure No. 1 Explains

Construction of Sectional Terminal capacitor Bank Circuit Parts

As 1. Section terminal capacitor Bank, with required leading KVAR 2. Running load traverse the 3. Line series impedance between 4. Sp's section length of 5. 30 km from 6. TSS consisting of 110 KV / 8. 25 Kv.

2. As per parts of figure No. 2 Explains Simplified circuit diagram of section terminal capacitor bank. Parts (1) Section terminal capacitor Bank Xc connected in series with (2) Line Impedance ZLS and parallel to (3) Running Load ZR between the (4) TSS and (5) Sectioning post.

3. As per parts of figure No. 3 Explains loss less leading KVAR Parts The (1) Running load between two (2) Line series impedance XLs2 among the one connected in series with (3) terminal capacitor bank and another (4) XLs connected in series with (5) TSS Load the line series impedance connected in series with terminal capacitor Bank acts as series reactor and only a low voltage dropped across it. hence the input voltage across running load at mid section (6) V - effect is equal to voltage across Vc capacitor

Since
Z effect = [(Xc - XLs)2 + R2]1/2
where Xc » XLs2 & R
hence Z effect = Xc

4. As per parts of figure No. 4 explains improvement of voltage at terminal end of the section due to section terminal capacitor Bank.

Parts

At no running load and circuit containing only line series impedance ZLs only as dropped voltage (1) Vc = Ic ZLs + Vm across the (2) section terminal capacitor Bank i.e. equivalent to the sum of capacitor current passing through

(3) Line series Impedance ZLs as.

(4) VLS = Ic ZLS and out put voltage of TSS (5) VO = VM 25 KV of the (6) TSS.

(5) As per parts of figure No (5) explains the improvement of voltage at Terminal end due to terminal capacitor Bank when running load in the section as Parts

The input voltage across (1) Running load Zr equal to the voltage across (2) Section terminal capacitor Bank Xc as (3) V2 = (VO - Vls) + Ic ZLs

Which the difference between voltage (4) VM of (5) TSS and (6) Line Series Impedance
(7) Ic ZLs and adding voltage drop due to capacitor current Ic.

(6) As per parts of Figure No. (6) explains the approximate calculation of improvement of Voltage Parts

(1) improvement of Voltage VQ = Ic (ZO + ZLS) at Terminal end of section due to (2) Section terminal capacitor Bank as capacitor current Ic flow through (3) Leakage reactance 20 of secondary of transformer (4) Line series Impedance ZLs connected with the (5) TSS having (6) voltage of Vm.

(7) As per parts of No. (7Figure) explains the approximate calculation of improvement of voltage of terminal end of section due to terminal capacitor bank for both sections of a TSS as
Parts

(1) Vc = IC1 (ZLS + Z0) + IC2 Z0 + VM for section (1) and

(2) Vc = Ic2 (ZLS + Z0) + Ici Z0 + VM„,

(3) Impedance of secondary coil of the 110 KV / 25 KV. Zo = 7.398 Ω

(4) Line series impedance Zls = 7.2 Ω (5) Out put VM, 25 KV of TSS
(6) 30 km of section (I) (7) 30 km of section (II)

I CLAIM

1) The section terminal capacitor bank circuit provided at each sectioning post, the terminal end of railway electrified traction section which in a manner such that parallel to the running loads and series to the traction line.

2) For the section terminal capacitor bank giving lossless leading KVAR to the running loads and power factor can be keeping at constant level.

3) For the section terminal capacitor bank done the improvement of line voltage at terminal end of railway electrified traction section, without taking additional supply current. Hence power can be saved in railway electrification at certain percentage.