Subject: [eman] terminology: power quality

From: Juergen Quittek <[email-masked]>
Date: Mon, 15 Aug 2011 13:14:29 -0700

Dear all,

Many thanks for the quick replies on the question about power quality.

Looking at the answers I might have asked another question first:
What is power quality? 

In past discussions we referred to a lot of quantities when using the term 
power quality. For me power quality has always been the "quality of power 
that a power provider delivers to consumers".  This is separate from 
the nominal power supply parameters and from the use that consumers 
make of power offered by the provider.

Power quality includes impedance and variation of voltage and frequency 
from agreed values. Excluded are current, (active/reactive/apparent) power, 
and the power factor. Current and power are mainly results of the consumer's 
behavior and not mainly driven by the quality of power provided. 

Of course, badly behaving consumers may deteriorate power quality for 
themselves and for other consumers connected and poor
power quality may influence the current and power at the consumer. 

Here are three groups of terms we should separate:

1. Nominal power supply
    (feel free to replace "nominal" with "nameplate" or "design")
  - type of current (AC or DC)
  - number of AC phases
  - nominal voltage (e.g., 100V, 230V)
  - nominal frequency (e.g. 50Hz, 60Hz)
  - min and max values for voltage and frequency

2. Power quality
  - the deviation of actual voltage from nominal voltage
    (can be realized by reporting the actual voltage and/or min/max voltage)
  - the deviation of actual frequency from nominal frequency
    (can be realized by reporting the actual frequency and/or min/max frequency)
  - the total harmonic distortion of voltage
In case of AC power, voltage and THD need to be measured per phase

Power quality can be measured at power inlets as "received/perceived quality"
or at power outlets as "provided quality".

3. Power usage
  - actual current
  - real/active power
  - power factor
  - reactive power
  - apparent power
  - phase (angle between current and voltage phase)
In case of DC power, only the current and real power are applicable
In case of AC power, all quantities need to be measured per phase

I think there is no question that we need to define a standard for reporting 
quantities listed under 1. and 3. (Some of the quantities related to complex power
under 3. are redundant. We may not need all of them.)

For me the main question is:

Do we need to define a standard for reporting power quality quantities listed under 2.?

Thanks,

    Juergen

---

From: "John Parello (jparello)" <[email-masked]>
Date: Mon, 15 Aug 2011 13:23:10 -0700

Hi Jeurgen,

For the values in Section 2 I think we'll need them.

 when the endpoints of a communication network are items "less
traditional" to this space they become more necessary.

For example an enterprise consisting of a communication network with 1
million PC based endpoints would not be concerned with those values.

Contrast that to an industrial setup with a communication network with 1
million endpoints of meters, motors, power generating, and
non-electrical energy endpoints  and it becomes relevant.

So I can't see a reason to exclude the information.  Allow it just make
it optional.

Jp

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of
Juergen Quittek
Sent: Monday, August 15, 2011 1:14 PM
To: eman mailing list
Subject: [eman] terminology: power quality

Dear all,

In past discussions we referred to a lot of quantities when using the
term power quality. For me power quality has always been the "quality of
power that a power provider delivers to consumers".  This is separate
from the nominal power supply parameters and from the use that consumers
make of power offered by the provider.

Power quality includes impedance and variation of voltage and frequency
from agreed values. Excluded are current, (active/reactive/apparent)
power, and the power factor. Current and power are mainly results of the
consumer's behavior and not mainly driven by the quality of power
provided. 

Of course, badly behaving consumers may deteriorate power quality for
themselves and for other consumers connected and poor power quality may
influence the current and power at the consumer. 

1. Nominal power supply

2. Power quality
  - the deviation of actual voltage from nominal voltage
    (can be realized by reporting the actual voltage and/or min/max
voltage)
  - the deviation of actual frequency from nominal frequency
    (can be realized by reporting the actual frequency and/or min/max
frequency)
  - the total harmonic distortion of voltage In case of AC power,
voltage and THD need to be measured per phase

Power quality can be measured at power inlets as "received/perceived
quality"
or at power outlets as "provided quality".

3. Power usage
  - actual current
  - real/active power
  - power factor
  - reactive power
  - apparent power
  - phase (angle between current and voltage phase) In case of DC power,
only the current and real power are applicable In case of AC power, all
quantities need to be measured per phase

I think there is no question that we need to define a standard for
reporting quantities listed under 1. and 3. (Some of the quantities
related to complex power under 3. are redundant. We may not need all of
them.)

Do we need to define a standard for reporting power quality quantities
listed under 2.?

Thanks,

    Juergen

_______________________________________________
eman mailing list
[email-masked]
https://www.ietf.org/mailman/listinfo/eman