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Req:loadshape - Requirements for loadshape built-in type

Application Concept

Loadshapes are used to represent a single or aggregate variation in power demand (or energy demand per unit of time) over time. A user may need to specify a loadshape as one of the following

  • an analog shape based on samples of consumption at given times;
  • a pulsed shape based on a series of random pulses that accumulate to a specified energy use of a specified time interval;
  • a modulated shape based on a series of modulated pulses of either constant period, amplitude, duration, or frequency;
  • a queued shape based on a series of random pulses from an accrued queue of demand; or
  • a scheduled shape based on a ramped demand that follows a daily schedule.

Requirements

R1

Analog shapes
Analog loadshapes shall represent loads that vary over time using sample obtained from a schedule.

R1.1

Energy scalar
When the energy demand is provided by the user, the schedule values shall be multiplied by a constant such that the energy used in each block is that specified by the user.

R1.2

Power scalar
When the power constraint is provided by the user, the schedule values shall be multiplied by the power value given.

R1.3

No scalar
When neither the energy or power scalar is provided by the user, the schedule values shall be multiplied by exactly 1.0.

R1.4

Randomization
When a standard deviation and either an energy or power scalar is provided by the user, the power amplitude output values shall be adjusted by the standard deviation multiplied by the triangle distribution from -3 to +3.

R2

Pulsed shapes
Pulsed loadshapes shall represent loads that recur periodically at random intervals with a probability such that the total energy used during a specified interval is constant.

R2.1

Reference schedule
The schedule provided by the user shall be the driving function for the loadshape.

R2.2

Constant energy
When a constant energy is specified, the total energy consumed by the pulses during the duration interval shall equal the constant energy value given. Either the duration, power, or pulse count shall be computed to satisfy the energy constraint, depending on which is not specified.

R2.3

Constant duration
The duration shall specify the duration interval over which the energy consumption is evaluated. Either the energy, power, or pulse count shall be computed to satisfy the duration constraint, depending on which is not specified.

R2.4

Constant power
When a constant power is specified, the power magnitude of the pulse shall be equal to the value given. Either the energy, duration, or pulse count shall be computed to satisfy the power constraint, depending on which is not specified.

R2.5

Pulse count
When the pulse count is specified, the number of pulses emitted during the duration interval shall be equal to the constant pulse count given. Either the energy, duration, or power shall be computed to satisfy the pulse count constraint.

R2.6

Randomization
When a standard deviation is provided by the user, the power amplitudes output values shall be adjusted by the standard deviation multiplied by the triangle distribution from -3 to +3.

R3

Modulated shapes
Modulated load shapes shall represent a continuous sequence of pulses that are modulated in either amplitude, frequency, or pulse-width such that a constant energy use is obtained over a specified duration.

R3.1

Constant energy
Specifying the constant energy shall constrain the loadshape to consume a fixed energy during the duration interval. The power, period, or pulse count shall be computed depending on which is not specified.

R3.2

Constant power
Specifying the constant power shall constrain the loadshape to produce a fixed power for each pulse. The energy, period, or pulse count shall be computed depending on which is not specified.

R3.3

Constant period
Specifying the constant period shall constrain the loadshape to consumed a fixed pulse period over the duration interval. The energy, power, or pulse count shall be computed depending on which is not specified.

R3.4

Constant count
Specifying the constant count shall constrain the loadshape to emit a fixed number of pulses over the duration interval. The energy, power, or period shall be computed depending on which is not specified.

R3.5

Randomization
When a standard deviation is provided by the user, the power amplitudes output values shall be adjusted by the standard deviation multiplied by the triangle distribution from -3 to +3.

R4

Queued shapes
A queued shape shall represent a tightly packed pulse train that occurs at random times.

R4.1

Energy
The energy value shall indicate the energy used by each unit of in the queue.

R4.2

Constant count
A constant count shall indicate that the number of pulses generated is fixed. When the count is fixed, the duration or the power of the pulses shall be computed depending on which is not specified.

R4.3

Constant power
A constant power shall indicate that the power amplitude is fixed. When the power is fixed, the count or duration of the pulses shall be computed depending on which is not specified.

R4.4

Constant duration
A constant duration shall indicate that the duration of a pulse is fixed. When the duration is fixed, the count or power of the pulses shall be computed depending on which is not specified.

R4.5

Queue value
An interval queue value shall accumulate the time-integral of the schedule value.

R4.6

Queue on threshold
The queue on threshold shall indicate the queue value at which the pulse train is generated.

R4.7

Queue off threshold
The queue off threshold shall indicate the queue value at which the pulse train ceases.

R4.8

Randomization
When a standard deviation is provided by the user, the power amplitudes output values shall be adjusted by the standard deviation multiplied by the triangle distribution from -3 to +3.

R5

Scheduled shapes
A scheduled loadshape shall represent a single daily load pulse.

R5.1

Weekdays
The weekdays shall specify which days of the week the pulse is generated.

R5.2

On-time
The on-time shall specify the time of day the pulse starts.

R5.3

Off-time
The off-time shall specify the time of day the pulse stops.

R5.4

Power
The power shall specify the amplitude of the pulse that is generated.

R5.5

Randomization
The power, on and off times shall allow users to min, mean, standard deviation, and max values for the time of day.

See also