By Engr. A.S.A Bada CEO (TCN) Transmission Distribution Interface bottlenecks and strategies for improved grid Stability By Engr. A.S.A Bada CEO (TCN)

GRID INTERFACE BOTTLENECKS Major 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 Spatial Network Coverage 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 Steps Taken: On-going Capacity Strengthening Projects Stations Added Capacity 1 Birnin Kebbi 330KV 150MVA 2 Kumbotso 330KV 3 Ayede 330KV 4 Onitsha 330KV 5 Afam 330KV 6 Kantagora 60MVA 7 Sokoto 8 Birnin Kebbi 9 Funtua 10 Katsina 11 Onitsha 40MVA

ON-GOING CAPACITY STRENGTHENING PROJECTS...............Ctd Stations Added Capacity 12 Akure 30MVA 13 Ukpilla 14 Amukpe 15 Delta 60MVA 16 Ajaokuta 17 New Haven 18 Akwanga 40MVA 19 G.C.M. 15MVA 20 Hadejia 21 Bauchi 22 Akangba

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 CONSTRAINTS Steps 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 Line 1 330/132KV 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

Too frequent 33KV trippings URGENT CONCERNS Too frequent 33KV trippings Inadequate notification of expansion projects

TOTAL NUMBER OF TRIPPINGS TOTAL ENERGY Undelivered (MWH) 33KV TRIPPINGS FOR NOV. WK 1 # DISTRIBUTION ZONES TOTAL NUMBER OF TRIPPINGS TOTAL ENERGY Undelivered (MWH) 1 ABUJA 126 1,628.95 2 BENIN 125 4,674.39 3 EKO 55 4,405.25 4 ENUGU 208 15,261.96 5 IBADAN 191 4,305.78 6 IKEJA 43 3,289.8 7 JOS 71 1,385.12 8 KADUNA 107 758.74 9 KANO 46 558.04 10 PH 121 4,201.89 11 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 Harcourt Port Owerri Uyo ALAGBADO Kebbi Birnin Minna Kaduna Abuja Jos Bauchi Gombe Damaturu Maiduguri Kano IIorin Ekiti Ado Lokoja Lafia Makurdi MAKURDI Enugu Akwa 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 CROSS RIVER AN AMBRA OSUN BAYELSA KOGI EDO ABIA RIVERS DELTA ONDO OYO ENUGU IMO ADAMAWA BORNO GOMBE BAUCHI EKITI LAGOS AKWA IBOM ATLANTIC OCEAN REPUBLIC OF BENIN OF CAMEROON OF CHAD NOTE: BULK SUPPLY POINT HYDROELECTRIC POWER STATION THERMAL POWER STATIONS 330 KV H SAPELE P/ST. POWER ST. OGUN Osogbo EGBIN NIGERIA Potiskum Niamey 132 kV 2 3 4 Aliade Mambila Bali AFAM 330KV LINES – MULTIPLE CIRCUITS 330KV LINES - EXISTING 2005 : new 2015 : new 3rd Circuit 2015 : 2010 : new 2010: new 2015 : new 2015 : new 2015 : new Zaria 2015 : 2nd Circuit P/ST. SAPELE 2015 : new Geregu Okitipupa Mambila Hydro Agip Some 330kV lines especially in Lagos and Delta areas could not be indicated on this geographical Map. See attached single diagram for Details.

TRANSMISSION GRID STRUCTURE WITH THE SUPER GRID IN PLACE TCN NETWORK WITH SUPERGRID ONITSHA KAINJI JEBBA/GS JEBBA/TS SHIRORO AJAOKUTA Abeokuta Ikeja Akure Benin Asaba Harcourt Port Owerri Uyo ALAGBADO Kebbi Birnin Minna Kaduna Abuja Jos Bauchi Gombe Damaturu Maiduguri Kano IIorin Ekiti Ado Lokoja Lafia Makurdi MAKURDI Enugu Akwa 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 CROSS RIVER AN AMBRA OSUN BAYELSA KOGI EDO ABIA RIVERS DELTA ONDO OYO ENUGU IMO ADAMAWA BORNO GOMBE BAUCHI EKITI LAGOS AKWA IBOM ATLANTIC OCEAN REPUBLIC OF BENIN OF CAMEROON OF CHAD TRANSMISSION LINE LEGEND BULK SUPPLY POINT HYDROELECTRIC POWER STATION THERMAL POWER STATIONS 330 KV H SAPELE P/ST. POWER ST. OGUN Osogbo EGBIN NIGERIA Potiskum Niamey 132 kV 2 3 4 Aliade Mambila Bali AFAM 330KV LINES – MULTIPLE CIRCUITS 330KV LINES - EXISTING 2005 : new 2015 : new 3rd Circuit 2015 : 2010 : new 2010: new 2015 : new TRANSMISSION GRID STRUCTURE WITH THE SUPER GRID IN PLACE 2015 : new 2015 : new Zaria 2015 : 2nd Circuit P/ST. SAPELE 2015 : new Geregu Okitipupa Mambila Hydro 700KV LINES – SUPER GRID Agip 700 / 330KV SUBSTATION NOTE: Some 330kV lines especially in Lagos and Delta areas could not be indicated on this geographical Map. See attached single diagram for Details.

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