EDC 5 (5236)  P3   
 
 
 
 
 
 
 
 
 
 
 
 
 
DRAFT  TANZANIA  STANDARD   
 
(Draft for comments only)  
 
Mini-Grid Systems  –  
 
Part 9:  Interconnection  of less than  
1MW  of Generation  with the National  Grid  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
TANZANIA  BUREAU  OF STANDARDS   
 
 
TBS 2017                                                                                              First Edition  2017   
 Table   of  contents    
0   Foreward..................................................................................................................... ....... ii   
1   Scope  ............................................................................................................................. ....1   
2   References............................................................................. ............................................  1   
3   Conditions  of Interconnection  with National  Grid........................................................  2   
4   Technical  Requirements................ ..................................................................................2    
4.1  
4.2   Existing  Guidelines  of Interconnection  with National  Grid..........................................2   
Requirements  for Interconnection...............................................................................  2   
5   Response  to local  area abnormal  conditions  ...............................................................  4   
5.1  
5.2   
5.3   Voltage  ........................................................................................................................  4  
Frequency....................................................................... .............................................  5   
Reconnection  to National  Grid ....................................................................................  5   
6   Power  Quality............................................ ........................................................................  5   
6.1  
6.2   
6.3  
6.4   Limitation  of dc injection..............................................................................................  5  
Voltage  Regulation  and Reactive  Power  Exchange...................................................  5   
Limitation  of flicker  induced  by the Mini-grid...............................................................  6  
Harmonics  ...................................... .............................................................................  6   
7   Islanding  Interconnection  Test specifications  and Requirements.............................  6   
7.1  
7.2   
7.3   Design  Tests  Protocol.................................................................................................6   
Surge  Withstand  Performance....................................................................................  7   
Commissioning  Tests  ..................................................................................................  7   
Addendum  1 - Business  Requirements  ................................................................................  8   
Business  Models......................................................................................................................  8   
Compensation  of Assets  to Mini-grid Operators  by Business  Model:......................... ..... 8   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
ii   
 
testing
  metering,
  protection,
  synchronization,
  stability,
  considerations,
  safety   contents,
  harmonic   maximum   frequency,   levels,
  voltage
  including
  TANZANIA    STANDARD     
 
 
 
 
0    
 
 
 
Forward    
 
 
This Standard  specify  requirements  for interconnection  of mini-grids  with the national  grid,  
 synchronization,   
monitoring,  metering,  protection  system  and continuity  of service  to the customers.   
 
The aim of this Tanzania  standard  is to provide  a framework  within  which  mini-grid operators   
can be assured  of their rights  and obligations  in the event  they wish to interconnect  the mini-  
grid with the national  grid operator.    
 
Considerations  include:   
 
Interconnection  of mini-grid generation  to the national  grid for generation  in excess  of 1MW   
is covered  by the existing  requirements  that govern  the interconnection  of SPPs    
 
Mini-grids   in  the  size  range   considered   here  have   economic   limitations   that  make   
compliance  with the standards  intended  for larger  system  excessive ly burdensome.   
 
The presumption  is that the size of the mini-grid generation  covered  by this standard  is small   
enough  that it cannot  affect  system  frequency  and makes  a negligible  contribution  to system   
fault  conditions.     It  is  the  responsibility   of  the  grid  operator   to  clearly   and  objectively   
demonstrate  that this is not the case before  imposing  any additional  requirements.   
 
While  several  parameters  of an electricity  supply  such as frequency,  continuity  of supply,   
voltage  level,  etc. must  be within  allowable  limits  to ensure  that the consumer  obtains   
satisfactory  performance  for their electrical  equipment  while  ensuring  that the demands  of  
the consumer  continue  to be met, the capital  and operating  costs  of doing  so should  be held  
to the minimum  possible.   
 
EWURA  is considering  a distribution  grid code  at the present  time and it may be that, if the  
grid code  can be adjusted  to apply  to mini-grids,  there  may not be a need  for an additional   
mini-grid code.     
 
This standard  focuses  on the specifications  for performance,  operation  and maintenance,   
 and  
interconnection  requirements.  It will lay genera l requirements  of power  quality,  islandin  g and  
evaluation  and periodic  tests.  This document  will apply  to aggregate  capacity  less than 1MW   
and  more   than  10kW.   This  Standard   is  derived   from  EWURA   guidelines   for  grid  
interconnections  and various  IEC Standards.   
 
Regulatory  framework  allows  small  power  producers  to supply  electricity  from both grid-  
connected   and  off-grid  power   supply   systems.   Small   Power   Producers   (SPPs)   with  
generation  capaci ty of less than 1MW  are exempted  from obtaining   a license  but  are  
required  to register  with EWURA.    
 
 
 
 
 
ii   
 and C, 2011   
rated  current  =< 16A  
techniques  — Section  2: Electrostatic  discharge  requirements   1   Scope    
 
This standard  provides  a framework  within  which  consumers  and mini-grid developers   
know  what the minimum  requirements  are for service  quality  including  service  voltage   
level ranges  at the consumer  premises,  maximum  harmo nic levels  in the wave  shape,   
and continuity  of service  as specified  in IEC Standards  EWURA  Distribution  and Grid  
Codes.    
 
This standard  provides  minimum  interconnection  requirements  for mini-grid generation   
and  associated   distribution   network   with  national   utility   (TANESCO)   and  specifies   
performance,   operation,   testing,   protection,   metering   and  testing   procedures.   The  
requirements  shall be met at the point  of common  coupling  (PCC).  The equipment,   
hardware  and software  shall meet  the specified  requirements  and standards  and shall be  
technically  qualified  to operate  under  the local service  conditions.   
 
Note 1
 This standard  shall be read in conjunction  with other  relevant  – Tanzania   
Standards,  applicable  standards  and specifications  to have uniformity,  compatibility  and  
standardization  in the distribution  system.   
 
 
2    
 
Normative   references    
 
For the purpose  of this Tanzania  Standard,  the following  references  shall apply:   
 
EWURA  draft Distribution  Grid Code,  June 2016  
 
Guidelines  for Developers  of Small  Power  Projects  in Tanzania   
 
Standardized  Small  Power  Purchase  Agreement  (SPPA)  for the Purchase  of Grid-  
Connected  Capacity  and Associated  Energy   
 
Standardized   Small   Power   Purchase   Agreement   (SPPA)   for  the  Purchase   of  
Capacity  and  Associated  Energy  to Mini-grids  
 
TANESCO  Grid Code  for Embedded  Generation   
 
Guidelines  for Grid Interconnection  of Small  Power  Projects  in Tanzania,  Parts  A, B,  
 
 
EN 61000 -3-2, Elect romagnetic  Compatibility  - Part 3: Limits  - Section  2: Limits  for  
harmonic  currents  emissions  (Equipment  input  current  up to and including  16A per  
phase)   
 
EN 61000 -3-3, Electromagnetic  Compatibility  - Part 3: Limits  - Section  3: Limitation  of  
voltage  fluctuations  and flicker  in low-voltage  supply  systems  for equipment  with  
 
 
IEC TS 61000 -3-4:1998  Electromagnetic  compatibility  (EMC)  - Part 3-4: Limits  -  
Limitation  of emission  of harmonic  currents  in low-voltage  power  supply  systems  for  
equipment  with rated  current  greater  than 16 A  
 
EN 61000 -4-2, Electromagnetic  compatibility  (EMC)  - Part 4: Testing  and measuring   
 
 
1   
 EN 61000 -4-5, Electromagnetic  compatibility  (EMC)  - Part 4: Testing  and measuring   
techniques  - Section  5: Surge  immunity  tests  
 
IEC 61727:2004  Photovoltaic  (PV) systems  - Characteristics  of the utility  interface   
 
IEC 62116:2014   Utility -interconnected  photovoltaic  inverters   - Test procedure   of  
islanding  prevention  measures   
 
3    
Condi tions   of  Interconnection   with  National   Grid   
 
 
Mini-grids  involve  small -scale  electricity  generation  (10kW  to 1MW),  which  serves  a limited   
number  of consumers  on distribution  grid that can operate  in isolation  from national  grid  
system.  Requirements  specified  in these  guidelines  are applicable  to all mini-grids  between   
10kW  and 1MW,  where  the mini-grids  are to be interconnected  with the national  grid. It is the  
objective  of these  guidelines  that such interconnections  appro priately  protect  the service   
quality  and facilities  of both the mini-grid operator  and the national  grid operator  at a cost  
that is not an excessive  burden  to either.   
 
a)  All mini-grids  considered  here are assumed  to have  loads  that are low enough  that  
 they can be served  for short  periods  by the interconnection  with the national  grid.   
 Such  mini-grids  can be provided  with simplified  interconnections.  In the event  this is  
 not  the  case,   either   because   the  load  of  the  mini-grid  is  high  or  because   the  
 capability  of the interconnection  is low, the interconnection  will be deemed  to be  
 subject  to the requirements  of Guidelines  for Grid Interconnecti on of Small  Power   
 Projects  in Tanzania,  Parts  A, B, and C, 2011.   
b)  Mini-grids  with generation  up to 100kW  shall interconnect  at low voltage  (400V)   
unless  otherwise  agreed  by the parties.   
 
 
4    
 
Technical   Requirements    
 
4.1   
Existing  Guidelines  of Interconnection  with National  Grid  
There  are existing  requirements  used to govern  the interconnection  of small  power  plants   
with the national  grid, but these  guidelines  are burdensome  for small  systems  in the 10kW  -  
1MW  range  and this standard  addresses  the technical  requirements  for interconnection  of  
such  systems.   
 
4.2   
Requirements  for Interconnection   
4.2.1    Interconnection  voltage   
 
a)  Mini-grids  with 100kW  or more  of installed  generation  shall be connected  at medium   
 voltage  which  may be an 11kV  or 33kV,  three  phase  three  wire system.   The choice   
 of interconnection  voltage  depends  on the voltage  level and carrying  capacity  of the  
 facilities  in the area and will be chosen  to match  the voltage  of the mini-grid  
 distribution  system,  if available.   
 
 
 
 
 
2   
 b)  Mini-grids  with less than 100kW  of installed  generation  shall be connected  at low  
 voltage,  400/230V,  three  phase  four wire system.   It may be necessary  to install  a  
 transformer  if the available  national  grid line is 11kV  or 33kV.   
 
c)  Equipment  requirements  for the mini-grid are the same  regardless  of voltage  of  
 interconnection.   
 
4.2.2    
Point  of Common  Coupling   
 
The Point  of Common  Coupling  (PCC)  is the point of interconnection  between  the mini-grid  
and the main  grid.  The location  of this point  shall be chosen  carefully  to allow  for access   
and installation  of necessary  equipment.     
 
4.2.3    
Equipment  at the Point  of Common  Coupling   
 
The following  equipment  shall, at a minimum  be located  at the PCC:   
 
a)  Fault  interrupting  equipment  designed  to ensure  that a fault on the mini-grid does  not  
interrupt  service  on the main  grid.  Appropriately  sized  fuses  fulfill this requirement.   
 
 
b)  A utility  grade  meter  installation  with associated  voltage  and current  transformers   
 capable  of metering  real and reactive  power  both into and out of the mini-grid.  Such   
 a meter  is commonly  referred  to as a four-quadrant  meter   
 
 
c)  A manually  operated,  lockable  disconnect  means  providing  a visible  open  between   
 the mini-grid and the main  grid.  
 
 
d)  Additional  equipment  may be installed  at the PCC upon  mutual  agreement.       
 
4.2.4    
Integration  of Mini-grid Grounding  System  with National  Grid Grounding   
System   
 
The grounding  scheme  of the mini-grid system  shall be integrated  with that of the  
national  grid, in case  the two grids  utilize  different  approaches  to grounding,  then  
grounding  transformer  may be required  to prevent  over voltages  that exceed  the  
rating  of the equipment  connected  to the national  grid or that disrupt  the ground  fault  
protection  system  of the national  grid. This might  occur  if the mini-grid uses  a four  
wire multi-grounded  MV system  while  the national  grid does not.   
 
4.2.5    Synchronization   
 
a)  The Mini-grid system  shall be synchronized  to the national  grid at the mini-grid  
 generator  locations  unless  otherwise  agreed  between  the parties.     
 
b)  Synchronization  of synchronous  rotating  machines  may be manual  or automatic,   
 except  that all schemes  shall contain  permissive  synch  check  relays  that inhibit   
 synchronization  until voltage,  frequency,  and phasing  are within  acceptable  limits.     
 
c)  Rotating  non-synchronous  machines  shall be brought  up to synchronous  speed   
 by auxiliary  means  before  being  connected  to the grid.   
 
 
 
3   
 d)  Power  electronics  inverters  designed  and programed  for grid tied operation  are  
 an acceptable  means  of synchronization.   
 
e)  Synchronization  of the mini-grid with the National  Grid system  shall not cause  a  
 voltage  fluctuation  at the PCC greater  than +/-5% of the prevailing  voltage  level  
 of the Nation  Grid at the PCC and shall meet  the specified  flicker  requirements.   
 
4.2.6    
Real Time  Metering   
 
There  is no requirement  that real-time metering  be installed  at the PCC unless  agreed  upon  
by both parties.    
 
5    
Response   to  Local   Area   Abnormal   Conditions    
Abnormal  conditions  can arise  on the national  grid electric  power  system  that requires  a  
response  from the connected  mini-grid. The required  response  is a separation  of the mini-  
grid  generation   from  the  system.       This  response   contributes   to  the  safety   of  utility   
maintenance  personnel  and the general  public,  as well as the avoidance  of damage  to  
connected   equipment,   including   the  mini-grid.  All  voltage   and  frequency   parameters   
specified  in this standard  shall be met at the mini-grid generator  location,  unless  otherwise   
stated.     
 
There  are three  cases  for responses  to abnormal  conditions:   
 
a)  The mini-grid generators  disconn ect from the main  grid, cease  generation  and wait  
 for the grid to become  stable,  then reconnect  after a time delay.   
b)  The mini-grid generating  system  disconnects  from the main  grid and continues  to  
 operate  as an islanded   grid. Reconne ction  is automatic  once  the grid becomes   
 stable.   Executing  this option  will require  additional  equipment  at the PCC than that  
 specified  in 4.2.3.   
c)  In  the  event   of  an  extended   outage,   the  mini-grid  generators   would   open   the  
disconnect  switch  from the main  grid and the mini-grid would  then be manually   
isolated  from the main  grid at the PCC.   The mini-grid generators  are then restarted   
to supply  the islanded  grid, but must  continue  to respond  to local disturban ces. When   
the main  grid outage  has been  resolved,  the mini-grid generators  would  be turned   
off, the distribution  component  of the mini-grid system  manually  reconnected  and  
then the mini-grid generators  turned  back on and resynchronized.   
5.1  Voltage    
The protection  functions  of the mini-grid generation  system  shall detect  the effective  (rms)  or  
fundamental  frequency  value  of each  phase -to-phase  voltage,  except  where  the transformer   
connecting  the local utility  electric  power  system  is a grounded  wye-wye configuration,  or  
single -phase  installation,  the phase -to-neutral  voltage  shall be detected.  When  any voltage   
is in a range  given  below,  the mini-grid generators  shall cease  to energize  the utility  electric   
power  system  within  the clearing  time as indicated.  Clearing  time is the time between  the  
start of the abnormal  condition  and the mini-grid ceasing  to energi ze the national  grid. For  
mini-grid generating  equipment  less than or equal  to 30kW  in peak  capacity,  the voltage  set  
points  and clearing  times  shall be either  fixed  or field adjustable.  For mini-grid generating   
equipment  greater  than 30 kW, the voltage  set points  shall be field adjustable.   
 
 
 
 
4   
 Table  1  
Parameter    Magnitude    Timing  (s)  
Over voltage    115 % of nominal  voltage    2  
Under  voltage    70 % of nominal  voltage    2  
 
Note  that  operation   of  the  mini-grid  generators   in  islanded   mode   may  have   different   
disconnect  levels  and timing  (seconds)  than those  specified  table  1.  The modified  schedule   
may be applied  when  the mini-grid is connected  to the national  grid upon  acceptance  by  
both parties   
 
5.2   
Frequency    
a)  When  the system  frequency  is in range  given  below,  the mini-grid generators  shall  
 cease  to energize  the national  grid within  the clearing  time as indicated.  For mini-grid  
 generating  equipment  less than or equal  to 30kW  in peak capacity,  the fre quency  set  
 points  and clearing  times  shall be fixed  or field adjustable.  For mini-grid generating   
 equipment  greater  than 30kW,  the frequency  set points  shall be field adjustable.   
 
b)  Adjustable  under  frequency  trip settings  shall be coordinated  with the area electric   
 power  system  operations.   
Table  2  
Parameter    Magnitude    Timing  (s)  
Over frequency    1,5 Hz above  nominal  frequency    1  
Under  frequency    1,5 Hz below  nominal  frequency    1  
 
c)  Note that operation  of the mini-grid generators  in islanded  mode  may have  different   
 disconnect  levels  and timing  (s) than those  specified  here.   The modified  schedule   
 may be applied  when  the mini-grid is connected  to the national  grid upon  acceptance   
 by both parties   
 
5.3   
Reconnection  to National  Grid  
After  a national  grid power  disturbance,  no mini-grid generation  reconnection  shall take  
place  until the measured  voltage  is within  +/- 10% of nominal  voltage  (per IEC 60038)  and  
frequency  range  of 49.0 Hz to 51.0 Hz. The mini-grid interconnection  system  shall include  a  
function  that will delay  reconnection  for a minimum  of five minutes  after the area steady -  
state voltage  and frequency  are restored  to the ranges  identified  above.   
 
6    
Power   Quality    
6.1  Limitation  of dc injection   
a)  The direct -current  injection  shall be in accordance  with IEC 61727.   
 
b)  The PV system  or other  solid state  generator  shall not inject  dc current  greate r than  
 1% of the rated  inverter  output  current  into the utility  ac interface.   
6.2  Voltage  Regulation  and Reactive  Power  Exchange   
The mini-grid operator  shall not regulate  the voltage  at the point  of common  coupling  (PCC)   
unless   specifically   coordinated   between   the  mini-grid  and  the  national   grid  operating   
companies,  but shall have  the ability  to present  and m aintain  a unity power  factor  at the  
PCC.   
 
 
 
 
5   
 b)  The  stated   test  specifications   and  requirements   are  universally   needed   6.3  Limitation  of flicker  induced  by the Mini-grid  
The mini-grid shall not create  objectionable  flicker  for other  customers  on the national  grid,  
defined  as compliance  with EN 61000 -6-1.  
 
6.4   
Harmonics   
a)  The harmonic  current  emission  shall be in compliance  with IEC TS 61000 -3-4 and  
 IEC 61727.   
 
b)  Even  harmonics  shall be less than 25% of the next higher  odd harmonics  listed  in the  
 IEC 61727.   
 
c)  Total  voltage  harmonic  distortion  shall be less than 5% at the rated  inverter  output.   
 Each  individual  harmonic  shall be limited  to the percentage  listed  in the following   
 table:   
Table  3  
Odd harmonics   Distortion  limit  
3rd through  9th  Less than 4.0%   
11th through  15th  Less than 2.0%   
17th through  21st  Less than 1.5%   
23rd through  33rd  Less than 0.6%   
 
7    
Islanding   Interconnection   Test  specifications   and  Requirements      
a)  This clause  provides  the test requirements  to demonstrate  that the interconnection   
 system  meets  the IEC specified  requirements  (IEC 62116).  The applicable  tests are  
 required  for all interconnection  systems.   The results  of these  tests shall be formally   
 documented.   
 
 for  
interconnection  of mini-grid including  synchronous  machines,  induction  machines,  or  
static  power  inverters/converters,  and will be sufficient  for most  installations.   
 
7.1   
Design  Tests  Protocol   
a)  This design  test shall be performed  as applicable  to the specific  interconnection   
 system  technology.  The test shall be performed  on a representative  sample,  either  in  
 the factory,  at a testing  laboratory,  or on equipment  in the field.  
b)  This test applies  to a packaged  interconnection  system  using  embedded  components   
 or to an interconnection  system  that uses an assembly  of discrete  components.   
c)  It shall interconnect  after five minutes  of stable  power  within  0.3 Hz of 50 Hz, but  
 disconnecti on is triggered  at 48.5 Hz (1.5 Hz difference)   
 
Table  4  
Synchronization  parameter  limits  for synchronous  interconnection  to the  
system,   
 
Aggregate  rating   
of mini-grid   
Frequency   
difference    
Voltage   
difference    
Phase  angle   
difference   
Units  (kVA)   (∆f, Hz)  (∆V, %)  (∆Φ, °)  
10 – 500  0.3  10  20  
501 – 1 000  0.2  5  15  
 
6   
 i)  
j)  f)  7.2  Surge  Withstand  Performance   
The interconnection  system  shall be tested  for the specified  requirement  in all normal   
operating  modes  in accordance  with EN 61000 -4-5 for all voltages  less than 4 kV.   
7.3  Commissioning  Tests   
All commissioning  tests  shall be performed  based  on written  test procedure  jointly  agreed   
between  mini-grid operator  and national  grid representatives.  The forms  and formats  must  
be developed  for testing  listed  below  or followed  as given  in EWURA  draft Distribution  Grid  
Code,  June  2016:   
 
a)  Visual  inspection  to ensure  grounding  requirements  have  been  implemented   
b)  Visual  inspection  to ensure  isolation  equipment  has been  placed  and operating   
c)  Visual  inspection  of all equipment  and devices  that necessary  equipment  has been   
 installed.   
d)  Operability  tests on the isolation  equipment  as  specified   
e)  Unintentional  islanding  functionality  test as specified   
 Cease  to energize  functionality  tests as specified   
g)  Monitoring  devices  testing   
h)  Metering  devices  testing   
 System  protection  relays  and devices  testing   
 Harmonics,  surge  withstand,  EMI testing   
k)  Hardware  and software  used  in the interconnection  testing   
l)  Grounding  integration  with national  grid operat or  
m) Design  verifications  to verify  BIL of equipment  and standards  certifications    
n)  Verification  of all system  parameters  to be within  specified  range   
o)  Other  tests which  falls under  the provision  of testing   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
7   
   Annex   A  
 (informative)    
Addendum   1  -  Business   Requirements    
 
 
Note:     In addition  to technical  requirements  it is to be noted  that mini-grids  are business   
enterprises  which  made  a good  faith effort  to supply  electricity  to the rural area in support  of  
national  objectives.   Such  an effort  can be successful  only when  the  investors  in the  
enterprise   can  be  reasonably   assured   of  recovering   their  inves tment.     It  is  therefore   
important  for this standard  to consider  conditions  under  which  such investors  should  be  
compensated  for loss of the utility  of such as asset,  as might  occur  if the national  grid were  
to take over the service  area and supplant  at lower  cost the service  supplied  by the mini-  
grid.  Such  compensation  would  be limited  to the cost of assets  as provided  elsewhere  in  
this standard  and would  not include  loss of projected  business  value.   EWURA,  as the  
statutory   regulator   of  the  sector   would   be  empowered   to  approve   each   transaction   
individually.     
 
 
A.1  Business   Models    
 
In addition  to technical  requirements  there  are different  business  models,  which  should  be  
considered   by  the  mini-grid  operators,   when   the  service   areas   of  the  mini-grid  are  
approached  by the national  grid. In the event  that the national  grid operator proposed  to  
serve  the same  consumers  as were  currently  being  served  by the mini-grid, it is expected   
that the national  grid operator  and the mini-grid operator  would  enter  into discussions  about   
the take-over of the mini-grid assets  and that a mutually  acceptable  arrangement  along  the  
lines of one of the business  models  indicated  would  be reached.   
 
Case -1: Continuity  in operation  of the mini-grid by the current  mini-grid operator,  as viable   
and sustainable  option  without  interconnection  with the national  grid  
 
Case -2: Continuity  in operation  of the mini-grid by the current  operator,  with interconnection   
to the national  grid   
 
Case -3: Continuity  in operation  of the mini-grid generation  as a power  supplier,  but sale of  
the mini-grid distribution  network  to the national  grid operator   
 
Case  4: Sale of generation  equipment/assets  and distribution  system  both to the national   
grid operator   
 
Case -5: Sale of distribution  system  to the national  grid operator  and removal  of generation   
system/equipment  by the mini-grid operator  for use elsewhere   
 
Case -6: Removal  of mini-grid assets  (both  generation  and distribution)  altogether  by the  
mini-grid operator  for use elsewhere.   
 
 
A.2  Compensation   of  Assets   to  Mini-grid  Operators   by  Business   Model:        
 
Compensation  of mini-grid assets  is the subject  of EWURA  SPP Rule 36.  
 
Compensation  would  be available  to a mini-grid operator  whose  system  was constructed  to  
the requirements  of TBS standards  as listed  below:   
 
 
 
8   
 TZS (XXX)  – Part 1:  Standard  for Uniform  Mini-grid Project  Planning   
 
TZS (XXX)  – Part 2: Standard  for Utility  Interactive  Inverters  for Mini-grids  
 
TZS (XXX)  – Part 3: Standard  for Distribution  Systems  for Mini-grids  
 
TZS (XXX)  – Part 4: Standard  for Wood  Poles  for Mini-grids  
 
TZS (XXX)  – Part 5: Standard  for Aerial  Bundled  Cable  for Mini-grids  
 
TZS (XXX)  – Part 6: Standard  for Low Voltage  Underground  Distribution  Systems  for Mini-  
grids   
 
TZS (XXX)  - Part 7: Standard  for Cables  for Low Voltage  Underground  Distribution  for Mini-  
grids   
 
TZS (XXX)  – Part 8: Standard  for Consumer  Electric  Metering  for Mini-grids  
 
TZS (XXX)  – Part 9: Grid Interconnection  Standard  for Mini-grids  
 
Compensation  for the value  of the assets,  but not for lost business  revenues,  would  be  
available  from the national  grid operator  by business  model  as follows:   
 
Case -1: No compensation   
 
Case -2: No compensation    
 
Case -3: Compensation  for the asset  value  of the distribution  system    
 
Case  4: Compensation  for the asset  value  of the generation  and distribution  system   
 
Case -5: Compensation  for the asset  value  of the distribution  system  only.  
 
Case -6: No compensation   
 
Compensation  would  be paid on the basis  of the depreciated  original  installed  value  of the  
asset,  with such original  installed  value  determined  by audited  records  from the time of the  
installation.   Depreciation  would  be taken  in accordance  with standard  utility  accounting   
practice.   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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