Transmission Distribution Interface bottlenecks and

strategies for improved grid Stability

ByEngr. A.S.A Bada

CEO (TCN)

GRID INTERFACE BOTTLENECKSMajor Causes include:• Radial state of network• Spatial network coverage• Transformer Capacity Constraints• Line Capacity Constraints• Switchgear Conditions• Grid indiscipline• Distribution network Conditions • Frequent trippings/Persistent faults

STATE OF NETWORK

• Radial State of network– Steps Taken: NIPP presently constructing the

closing of the loop to Jos with a DC 330KV line• Spatial Network Coverage

– Steps Taken: 26No. Lines and Substation projects awarded in 2010 and 18No. Lines and Substation projects to be awarded before the end of this year (4 New substations to be constructed in the North Eastern part and 5 New Substations in the NW )

Transformer Capacity Constraints

Stations Added Capacity1 Birnin Kebbi 330KV 150MVA2 Kumbotso 330KV 150MVA3 Ayede 330KV 150MVA4 Onitsha 330KV 150MVA5 Afam 330KV 150MVA6 Kantagora 60MVA7 Sokoto 60MVA8 Birnin Kebbi 60MVA9 Funtua 60MVA10 Katsina 60MVA11 Onitsha 40MVA

Steps Taken: On-going Capacity Strengthening Projects

ON-GOING CAPACITY STRENGTHENING PROJECTS...............Ctd

Stations Added Capacity12 Akure 30MVA13 Ukpilla 30MVA14 Amukpe 30MVA15 Delta 60MVA16 Ajaokuta 60MVA17 New Haven 60MVA18 Akwanga 40MVA19 G.C.M. 15MVA20 Hadejia 60MVA21 Bauchi 60MVA22 Akangba 60MVA

ON-GOING CAPACITY STRENGTHENING PROJECTS...............Ctd

• TCN expects delivery of Power Transformers from 1st quarter of 2012–4No. 300MVA 330/132KV Transformers–5No. 150MVA 330/132KV Transformers–10No. 100MVA 132/33KV Transformers–10No. 60MVA 132/33KV Transformers

LINE CAPACITY CONSTRAINTSSteps Taken:• Gombe – Yola 330kV line has been energized• 2nd Benin – Ajaokuta 330kV line has finally

been rehabilitated• 3rd Benin –Onitsha DC 330kV line to be

commissioned soon• Re-conductoring of weak and old lines (e.g

Aba – Itu, Itu – Calabar , Afam – PH, Delta – Effurun, Ota - Papalanto) with higher thermal capacity conductors are in various stages.

OUTCOME OF STRATEGY MEETINGS# Drop down Sub. By WBank Source Line1 330/132KV Substation at Ogijo

(Ikorodu)Egbin – IkejaWest 330KV Line

2 330/132KV Substation at Epe Omotosho – Aja Line

3 330/132KV Substation at New Kano

Kaduna – Kano 330KV line

4 132/33KV Substation at Choba - PH

Omoku – PH Mains Line

5 132/33KV Substation at Awkunanu - Enugu

New Haven – Orji Line

6 132/33KV Substation at Kaltugo Gombe – Yola Line

URGENT CONCERNS

•Too frequent 33KV trippings

• Inadequate notification of expansion projects

33KV TRIPPINGS FOR NOV. WK 1#

DISTRIBUTION ZONESTOTAL NUMBER OF TRIPPINGS

TOTAL ENERGY

Undelivered (MWH)

1 ABUJA 126 1,628.952 BENIN 125 4,674.393 EKO 55 4,405.254 ENUGU 208 15,261.965 IBADAN 191 4,305.786 IKEJA 43 3,289.87 JOS 71 1,385.128 KADUNA 107 758.749 KANO 46 558.0410 PH 121 4,201.8911 YOLA 63 533.66

MITIGATION STRATIGIES FROM DISCO’s

• Submission of accurate data on customer population and installed capacity (MVA)

• De-loading of 33KV Feeders through network expansion

• Explore use of lattice towers for long 33KV Lines• Due to inadequate generation power should be

given to some feeders then transferred to the others over time RATHER THAN pro-lateral sharing of power on all the feeders at the same time

MITIGATION STRATIGIES FROM DISCO’s

• Adherence to operational instructions• Gradual phase out of wooden cross

arms with fibre• Movement of load on designated

under frequency relays should henceforth stop

• Disciplinary actions should be meted out on erring staffs

MITIGATION STRATIGIES FROM DISCO’s.......

• Supervising operators should henceforth be alive to their responsibilities

• Issuance of a circular from their respective CEO’s demanding strict adherence to operational instructions

Further Key Transmission Grid Challenges

• Due to urbanization and environmental issues, it is becoming increasing difficult to acquire Right- Of-Way for new lines

• Increased power demand due to growth in industries and population

• Vandalization of transmission lines• Adverse Weather Conditions• Poor power quality• Transmission grid upgrades cannot keep

pace with power demand

STRATEGIES- Work is on-going on grid expansion.

- Significant Investment is being made to effectively double existing capacity through the NIPP intervention

- Line trace issues (mitigation against frequent line trips) have been taken more seriously with focus on contracting companies with requisite tools to work on difficult terrains

- Frequency stability has been largely achieved with some units in Delta, Kainji and Egbin providing frequency support in form of reserve margins

- Deployment of FACTS facility at strategic node of the network (e.g Kano, Gombe)

- Work has commenced in deploying the Supergrid network

330KV GRID STRUCTURE AFTER COMPLETION OF ALL ON-GOING PROJECTS

ONITSHA

KAINJI

JEBBA/GS

JEBBA/TS

SHIRORO

AJAOKUTA

Abeokuta

Ikeja

Akure

Benin

Asaba

PortHarcourt

Owerri

Uyo

ALAGBADO

BirninKebbi

Minna

Kaduna

Abuja

Jos

Bauchi

Gombe

Damaturu

MaiduguriKano

IIorin

AdoEkiti

Lokoja

Lafia

Makurdi

MAKURDI

EnuguAkwa

Umuahia

Ibadan

Sokoto

Gusau

Katsina

Hadejia

Jalingo

Yola

Abakaliki

Calabar

JIGAWA

KANO

KATSINA

SOKOTO

ZAMFARA

KEBBI

KWARA

KADUNA

ABUJA

NIGER

NASSARAWA

TARABA

YOBE

PLATEAU

BENUE

EBONYI

CROSSRIVER

AN AMBRA

OSUN

BAYELSA

KOGI

EDO

ABIA

RIVERSDELTA

ONDO

OYO

ENUGU

IMO

ADAMAWA

BORNO

GOMBE

BAUCHI

EKITI

LAGOS

AKWAIBOM

ATLANTIC OCEAN

NIGER

REPUBLICOF BENIN

REPUBLICOF CAMEROON

REPUBLICOF

CHAD

NOTE:

BULK SUPPLY POINT

HYDROELECTRIC POWER STATION

THERMAL POWER STATIONS

330 KV

H

SAPELEP/ST.

DELTAPOWER ST.

OGUN

Osogbo

EGBINP/ST.

NIGERIA

Potiskum

Niamey

132 kV

2

3

2

3

4

2

2

Aliade

Mambila

Bali

2

AFAM POWER ST.

2

2

330KV LINES – MULTIPLE CIRCUITS

330KV LINES - EXISTING

2

2

2005 : new

2

2015 : new

2015 : new

2015 : new

2015 : 3rd Circuit

2010 : new

2015 : new

2010: new

2

2

42015 : new

SAPELE

P/ST.

Okitipupa

Geregu

2015 : 2nd Circuit

Agip

Zaria

2015 : new

2015 : new

2015 : new

2015 : new

Mambila Hydro

Some 330kV lines especially in Lagos and Delta areas could not be indicated on this geographicalMap.See attached single diagram for Details.

TRANSMISSION GRID STRUCTURE WITH THE SUPER GRID IN PLACE

ONITSHA

KAINJI

JEBBA/GS

JEBBA/TS

SHIRORO

AJAOKUTA

Abeokuta

Ikeja

Akure

Benin

Asaba

PortHarcourt

Owerri

Uyo

ALAGBADO

BirninKebbi

Minna

Kaduna

Abuja

Jos

Bauchi

Gombe

Damaturu

MaiduguriKano

IIorin

AdoEkiti

Lokoja

Lafia

Makurdi

MAKURDI

EnuguAkwa

Umuahia

Ibadan

Sokoto

Gusau

Katsina

Hadejia

Jalingo

Yola

Abakaliki

Calabar

JIGAWA

KANO

KATSINA

SOKOTO

ZAMFARA

KEBBI

KWARA

KADUNA

ABUJA

NIGER

NASSARAWA

TARABA

YOBE

PLATEAU

BENUE

EBONYI

CROSSRIVER

AN AMBRA

OSUN

BAYELSA

KOGI

EDO

ABIA

RIVERSDELTA

ONDO

OYO

ENUGU

IMO

ADAMAWA

BORNO

GOMBE

BAUCHI

EKITI

LAGOS

AKWAIBOM

ATLANTIC OCEAN

NIGER

REPUBLICOF BENIN

REPUBLICOF CAMEROON

REPUBLICOF

CHAD

TRANSMISSION LINE LEGEND

BULK SUPPLY POINT

HYDROELECTRIC POWER STATION

THERMAL POWER STATIONS

330 KV

H

SAPELEP/ST.

DELTAPOWER ST.

OGUN

Osogbo

EGBINP/ST.

NIGERIA

Potiskum

Niamey

132 kV

2

3

2

3

4

2

2

Aliade

Mambila

Bali

2

AFAM POWER ST.

2

2

330KV LINES – MULTIPLE CIRCUITS

330KV LINES - EXISTING

2

2

2005 : new

2

2015 : new

2015 : new

2015 : new

2015 : 3rd Circuit

2010 : new

2015 : new

2010: new

2

2

42015 : new

SAPELE

P/ST.

Okitipupa

Geregu

2015 : 2nd Circuit

Agip

Zaria

2015 : new

2015 : new

2015 : new

2015 : new

700KV LINES – SUPER GRID

700 / 330KV SUBSTATION

Mambila Hydro

Some 330kV lines especially in Lagos and Delta areas could not be indicated on this geographicalMap.See attached single diagram for Details.

NOTE:

TCN NETWORK WITH SUPERGRID

THANK YOU