A micro hydro turbine driving
an induction generator is like a finely tuned instrument. It runs most
efficiently when water flow and head pressure resonate mechanically with the
turbine geometry and the rotational speed. The rotational speed generates a
precise pitch of 60 cycles per second which in turn is tuned to resonate
(electrically) with the load and a bank of capacitors to keep currents
oscillating through the copper windings of the generator and create magnetic
fields in synchrony which in turn produce the current that we can use to light
up our lives.
Since there are significant
energy flows to be controlled and contained, it is important to understand how
to control the energy smoothly, avoiding sudden surges or stepwise impacts in
both the electrical as well as the hydraulic circuits. The operator, typically an engineer or highly
trained technician, must understand, and be able to predict the result of
turning On or Off any circuit breaker, switch or valve before actually touching
a breaker, valve or controlling device. (In many localities grid-connected
power plants are required to be operated under the supervision of an engineer.)
Always check the readouts first to find out what loads are being powered when
making any changes, and try to anticipate the result of the adjustment and the
effects on the connected load. This manual will explain each switch, breaker,
valve and controller and the function each serves.
This manual will give the
procedures for startup of the plant, planned shutdown, unplanned shutdown and
subsequent startup procedure. Monitoring and metering will also be explained.
It may be useful for the more experienced operator to refer to the diagrams for
further insight to the operation of this plant.
Definitions as they apply to the Buttermilk Micro
(Starting from the top.)
Storm Water Diversion: currently a pair of logs placed at an angle ~12 feet upstream from
the water intake. Their function is to protect the down stream intake structures
during extreme weather events. (Maintenance or future enhancement / automation
Water flow measuring
weir: located immediately upstream from the
water intake. Functions to get an approximate measure of total water flow
reaching the intake. (Maintenance or future enhancement / automation project.)
Slide gate: at the entry to the flume, function is to shut off water at the
water intake during severe weather events or flume repairs.
Water intake: the 8” x 48” rectangular opening in the upstream end of the flume.
Warm water feed: the warm Honderosa spring water fed via (blue) underground pipe that
keeps the water intake from freezing closed during most subzero winter nights.
Flume: the structure that currently carries the water from the water intake
to the gravel baffle (and screening) box. (Maintenance or future enhancement
Minimum flow bypass: the circular opening in the flume bottom that insures the escape of
a minimum of 200 Gallons / minute to keep the waterfall hydrated. (Maintenance
or future enhancement / automation project.)
Gravel baffle box: the 4’ x 4’ x 5’ high (wood) box (Maintenance and / or future
enhancement / automation project.) with the integral second gravel chamber and
attached first gravel chamber, ball and chain flush valves, moving screen,
screen drive mechanism, head valve, head valve drive / operator, and attached
to the flume upstream.
Gravel Chambers: the first gravel chamber removes most negative buoyancy material
that did not fall out of the minimum flow bypass. The second gravel chamber
mostly collects fine sand and mud. (Maintenance or future enhancement /
Moving screen: the HDPE conveyor belt screen that functions to keep floating or
neutral debris from going down the penstock and clogging the turbines. The
screen duty cycle can be adjusted so it does not clog itself with heavy debris
loads or frazzle ice formation. (Maintenance and / or future enhancement
Frazzle ice: the slushy watery ice that forms in the shallower upstream rapids as
water is super-cooled during sub zero nights. The frazzle ice solidifies
immediately when it meets any cold or metal surface and blocks water flow. Once
ice covers the stream no further frazzle ice will form and the water will run
unimpeded underneath the ice cover, more so if snow also covers the ice. Even
water falling vertically will be covered with ice.
Head valve: the butterfly valve and operator (motor and drive circuitry) at the
bottom outlet of the gravel baffle box where the penstock connects.
Penstock: the 8” insulated or buried steel pipe that keeps the water contained
as the pressure increases
going down to the powerhouse.
In the Power House
Green LED: indicates normal, OK,
valve open, valve opening, green condition.
Red LED: indicates fault, valve
closed, valve closing, red condition.
Orange Neon: indicates no power or
reverse power flow from grid to generator. The Orange will extinguish when generator is operating normally and
NO: Normally Open contacts /
NC: Normally Closed contacts /
Valve1: The large PVC valve with
red hand wheel that controls water flow to GEN1.
Valve2: The large PVC valve with
red hand wheel that controls water flow to GEN2.
Valve3: The large PVC valve with
red hand wheel in the middle that controls the dumping of water and debris into
the discharge pit.
GEN1: Smaller 10kW turbine /
GEN2: Larger 15kW turbine /
Rotork1: Valve and valve controller
on GEN1 functions to automatically keep
the speed of GEN1 constant when set to AUTO.
Rotork2: Valve and valve controller
on GEN2 functions to automatically
keep the speed of GEN2 constant when set to AUTO.
Electronic controlling devices:
Main distribution panel
will add more, see comment
balloons on Buttermilk manual 1.2.PDF
I. Start-up of water
flow at intake
During warm weather months
the flow of water to the turbine may be started (acquire ‘green’ condition) by
following these steps.
a. All power house valves
closed, No water flow.
b. GEN(1 and 2) Rotork in
manual / local mode and operated to CLOSED position.
c. Utility power present and
fed through to homes, transfer switches in Normal mode, not Utility /
1. Insure that there is at
least enough flow in the stream to support turbine/GEN1 operation. This can be
judged by observing the flow into the flume. Standing on the flume looking
upstream, the water should cover ~80% of the width of the sloping bedrock stone
weir, or within ~20% of the right side of the flume. (This measurement method
should be refined when the temporary intake structures are made permanent by
having a constant slope and marks ground or cemented into the trailing edge of
the bedrock leading into the flume.)
2. Check that the moving
screen (trash rack) is clear and operational. (see:Moving Screen Maintenance)
Flush the 1st and 2nd sand and gravel settling chambers by pumping the ball
valves (via stainless chains) up and down several times or until the water
flows clean from the flush opening. (This procedure should be refined when the
temporary intake structures are made permanent.)
The head valve can be
operated from the powerhouse by a single push of the button on the Head Valve
and Communications control box, observing the green LED for valve open and red
LED for valve closed. An additional red/green LED lights only while the valve
is moving to its newly commanded position, which takes ~100 seconds. Each push of
the button reverses the operation of the head valve from open to close and vice
versa with a 2 second delay.
Continuous operation of the
trash rack can currently be implemented manually from a control box at the top
of the falls in the old pump house. (Maintenance or future enhancement
II. Start-up of
conditions are: all the above and:
1. The ORU utility grid is assumed to be
always present when starting up. If ORU fails while BMH is running, BMH
continues independently, disconnected from the grid automatically via the
Beckwith 3410 intertie protection device.
Open Head Valve (press button
once on Head Valve and Communication box), wait for valve to open as indicated
by ONE green LED. (the ‘green’ condition)
After 15 minutes check that
pressure is stable at 95 PSI. (It was previously insured that a good volume of
water is available in stream above and no ice/sand/gravel is present in penstock
(See: “Winter Icing
Conditions” for cautions.)
2. Utility grid power ON.
Beckwith 5 minute timer expired and ‘Output 1’ RED LED is ON and GREEN LED is
3. Top four load side
breakers ON. We are using grid power as indicated on the Net Grid meter lower
right in Beckwith enclosure.
4. Bottom six Generator side
breakers OFF. We are not making any power yet.
5. Check for nominal meter
readings of Honders ~1-3kW, Buyske ~ 1-3kW, NET from Grid −3kW to −8kW on PM620
meter in lower right hand corner of Beckwith enclosure. (The signs will change
once the PM620ʼs are directionally adjusted to conform to Utility practice.)
6. REV PWR RESET to OFF
(down) (located under Beckwith 3410)
the GEN 1 or 2 (which ever one is being started) manual main (RED WHEEL) valve
to 50%. A red line on the valve stem indicates 50%.
8. Open GEN 1 or 2 Rotork in
MANUAL mode to get RPM ~2000 using manual mode with the lever and hand-wheel or
local control with open / close switch. Observe open / close LEDs in Rotork
housing, after alternating red/green both should be OFF indicating speed is
8. Switch REV PWR RESET to ON
(up) (located under Beckwith 3410)
9. GEN1or 2 breaker ON, never
breaker ON for GEN1. C1 and C2 breaker ON for GEN2. (Do not run both GENs
11. Switch Rotork valve to
REMOTE (automatic enabled). The Rotork controller should now open the valve
slowly to maximum power.
12. Observe pressure gauge
reading, (~90 PSI GEN 1, ~80PSI GEN 2), holding steady, not dropping for lack
of water at the top or too much power input to GEN2. If too much power revert
to manual control, 5/8 open 80 psi.
Check that the Reverse Power
Relay ORANGE light is OFF.
Check PM620 Grid Power,
Summary kW3Ø 5 to15 depending on house loading.
Check that power factor, PF3Ø
> .90 or as close to 1.000 as you can get by switching breaker C2 and/or C3.
Closer to 1.00 is better. If PF3Ø is - (negative) then turn off C3 if you can
get closer to +or- 1.00
Check that the pressure
remains stable at ~90 PSI GEN 1, ~80PSI GEN2.
If it is raining/snowing be
sure to set the trash screen to continuous mode to prevent clogging.
13. GEN1or2 set the Rotork
valve controller to REMOTE (automatic enabled).
14. Set (Honders and Buyske) house
meters to read kW3Ø.
15. Switch REV PWR RESET to
ON (down) (This may change with further automation.)
III. Shut-down of
During warm weather months
the flow of water to the generator may be stopped (‘red’ condition) by closing
either the head valve, the manual valves, or the Rotorks in the powerhouse and
following this sequence:
a. Head Valve open, normal
water flow. ‘Green’ condition.
b. GEN(1 or 2) operating,
Rotork in automatic control mode.
c. Utility power present and
BMH power fed back to grid and through to homes, transfer switches in Normal
mode, never Utility / Emergency. (This can be assured by opening the main
breaker, interrupting the O&R ‘Emergency’ source from the ASCO transfer
switch at the house.)
Sequence to follow:
1. Set the GEN(1 or 2) Rotork
2. Switch REV PWR RESET to
OFF (up) (located under Beckwith 3410)
3. Set the Rotork to manual /
local control mode.
4. While observing the Valve
position indicator on the Rotork operate the valve to its fully closed
position. All should be quiet now.
5. Turn off all (lower)
Generator side breakers. Do not touch the upper 4 Load side breakers.
During cold weather months or
anytime there is a danger that BMH may stop generating power it is best to
switch REV PWR RESET to OFF (up) (this will change with further automation.)
During cold weather months
the stream water flow must be kept from entering the penstock by:
1. Lowering the slide at the
entry to the flume. (needs improvements with the rebuild)
2. Pull up 10” and hook both
gravel flush ball valves.
3. Check that warm water
flows down penstock to keep it from freezing solid.
4. Turn off all (lower)
Generator side breakers. Do not touch the upper 4 Load side breakers.
Conditions — CAUTION
years I have made continual improvements to the ‘temporary’ intake structures
to mitigate some of the problems with slush and ice in winter, leaves in the
fall, sand gravel, rocks, logs and debris washed down every time it rains more
than an inch or two overnight.
winter problems would be greatly reduced or eliminated if there was a deeper
reservoir to draw water below the surface ice layer, but not so low as to suck
up sand and gravel. ( An 8” high x 48” wide opening just above the low,
upstream, end of the moving screen could be opened to take water in through the
screen if the water level is raised just above this opening.) The first fall
excursions to single digit temperatures will probably not cause slushy (frizzle
ice) water. But after a day or two of sub-zero nights frizzle ice will start to
dam up flowing water especially any place where there is the slightest
restriction or shallow water flow. So the first problem occurs under the storm
water diversion logs which will definitely have to be repositioned or removed
in winter. This means that they probably will not be able to be repositioned
before the spring thaws to deflect the likely storm waters.
second problem area is the 8”x48” primary intake at the upstream end of the
flume. The water arrives super cooled to below freezing, carrying slush. Icicles
form along the top edge of the 48” wide opening and grow rapidly together to
the bottom of the flume and, with the slush, completely block the inlet in
short order. Then the upstream water rises until it flows around the plugged up
intake opening, dropping the head pressure, and starving the turbine.
down the power plant under these conditions is both difficult and risky. The
valve stems and motor drivers tend to be frozen in place or are unable to close
completely because of the cold and icing. This allows a trickle of water to
continue down the pipe with increased likelihood of freezing inside the
penstock. All means should be employed to
keep a flow of water going down the penstock to keep that from freezing solid
and potentially bursting or splitting or having it frozen until spring thaws.
To facilitate this I have installed piping that carries warm water (45°F) from
our hillside spring (and domestic water supply) to the intake structures. This
warm water is normally directed to the intake opening to keep that from
freezing but if a complete shutdown in winter is desired then the warm water is
redirected to the penstock in the trash conveyor enclosure by a diversion valve
(yet to be installed). Then to complete a safe shutdown both gravel dump ball
valves must be lifted 10 inches and chained open. The slide gate at the
upstream intake should be slid all the way down to minimize water entry. Now
the only water going down the penstock should be the warm 45° water from the
extreme caution when restarting the plant after a shutdown forced by extreme
cold. It is possible for ice to come loose from the penstock walls and damage
valves, pipes and turbines. If ice in the penstock is a possibility then the
dump valve should be opened slightly to allow a low flow (~60GPM) through for 8
to 12 hours to insure all the ice is melted before starting the turbine
risky procedures in plant operation are shut down and startup. A running plant
is far less prone to be damaged by nature or human error.
Gravel baffle box,
aka Trash rack / conveyor.
Gravel baffle box is still the (2007) original temporary wood construction and
needs to be reconstructed of more durable materials. At the same time the badly
worn down concrete and stone dam needs to be restored to its original height as
planned in this earlier graphic:
rebuilt trash conveyor box may be left in the current place and configuration
with just an 8” x 48” opening added to the upstream side just above the lower
end of the trash conveyor belt to allow
water to enter. The trash conveyor has been very effective in minimizing fall
leaf drop and debris problems. The higher water level behind the dam will
minimize freezing problems in winter.
Gravel Baffle Box: Raising the water level behind the low stone dam will
minimize winter icing problems.
The ORU Net Meter
The debiting and crediting of
kWh is done inside the ORU NET METER in real time as power flows back and
forth as local demand and generation fluctuates.
Beckwith M3410 Grid
Intertie Protection Relay
The Beckwith relay monitors
the grid side of the system. If the grid goes out of normal bounds it will
separate BMH from the grid. During normal BMH-grid-connected operation, if the
grid goes out of bounds it will also pull BMH
out of bounds with it.
(Approximate bounds are: 59.3 Hz to 60.5 Hz and 211.2v to 288V for a 240 V system)
When the programmed trip
point is reached the Beckwith will separate BMH from the defunct grid and the
BMH valve controller will attempt to match local generation to the new load
conditions for OFF GRID operation, sparing the line men working on the dead
grid, while continuing autonomous (also called 'islanded') operation.
Reverse Power Relay
The Reverse Rower Relay will
monitor the direction of energy flow in the connection between the BMH
generator and everything else. If the water flow decreases or stops and the
generator output starts to drop below a programmable minimum, the Reverse Rower
Relay will open the relay in the
preventing grid power from flowing to the idled generator and causing it to
'motor'. Refer to the One Line Diagram to see more detail, or the Power House
wiring diagram for even more detail.
All monitoring functions are
provided via webserver at: http://Powershack.Shacknet.nu:1300
After entering a username and
password all real time data as well as accumulated totals may be read remotely
using a standard web browser. (Chrome / Mac seems to work the best.)
Grid Supply to BMH
The Beckwith 3410 automatically switches from ORU to BMH and vice versa, depending on the
adequacy of BMH generation to meet the demands of Honders and Buyske
Individual ORU Accounts and Automatic Transfer Switches
With all electrical service
to homes drawn through BMH, the individual accounts with ORU, as well as
the automatic transfer switches previously installed, are redundant and
ORU residential accounts
may be discontinued. When BMH has disrupted operation, grid power is directed to each residence through the BMH
account, using energy credit accrued.
Intelligent Load Controllers (DILCs)
DILCs installed on water heaters,
clothes dryers or other high-demand appliances were intended to modify the jolt
of instant demand on the BMH system by ramping-up the power from BMH to the
appliance, thereby lessening brown-outs or other effects on the system. With the
grid connection, the system reactive power is greater, and thus able to handle the fluctuating loads and obviating the need for the DILCs.
As long as the trash screen
is in place and operational and gravel is flushed after every heavy rain fall,
cleaning of turbines is unnecessary.
The job of generator bearing
replacement maybe too cumbersome to be done in the powerhouse. At the point that
bearings become worn and need replacement, the turbine and generator may be disconnected
from the system and taken to a qualified pump repair service.
I am a retired electronics engineer, educator, businessman and builder of micro hydro installations for fun and sometimes even profit. This one uses a pump/motor as a turbine/generator using a 200 ft waterfall in our back yard. It is currently producing 15KW. I will be tweaking it to take advantage of greater winter flows.
It's not the product, but the process... I enjoy doing the most with the least. So this renewable energy source cost less than $2 per watt of capacity not counting any labor and engineering.