Your questions answered: Benefits of powerful embedded metering at the source of consumption

The Oct. 5, 2017, “Benefits of powerful embedded metering at the source of consumption” webcast presenters addressed questions not covered during the live event.
By Robert Martin, George Roscoe, and Bala Marimuthu, Siemens October 11, 2017

Energy management is a growing practice among large and medium size companies. Successful energy management requires detailed information on how the energy is being used. However, this information is not available in facilities that are not actively being monitored. For proper energy management, it is necessary for facility managers to understand how and where energy is being consumed.

Energy efficiency is the first step in achieving sustainability in buildings and helps to control increasing energy costs while reducing environmental footprints. Energy management system can provide metering, submetering, and monitoring functions that allow facility managers to gather data that allows them to make more informed decisions about energy use.

The presentation will provide a general overview of the submetering and integration capabilities with standalone, energy management, and cloud solutions. Discussions around unique “embedded” solutions will allow consulting and specifying engineers to understand the benefits of an integrated SEM3 solution compared to traditional monitoring.

Presenters Robert Martin, business development professional, Siemens; George Roscoe, product manager, Siemens; and Bala Marimuthu, product manager, Siemens, responded to questions not answered during the live Benefits of powerful embedded metering at the source of consumption webcast on Oct. 5, 2017.

Question: How would you best integrate metering on a supervisory control and data acquisition (SCADA) system based on IEC 61850-2017: Communication networks and systems for power utility automation?

Answer: IEC 61850 is a standard protocol for vendor-agnostic engineering of the configuration of intelligent electronic devices for electrical substation automation systems to be able to communicate with each other. Siemens does have power meters with native IEC 61850 protocol for integrating with systems such as SCADA based on IEC 61850.

Q: How do you ensure meters are integrated into the building automation system (BAS) and/or electrical power monitoring systems?

A: Ensure that the meters have native BACnet IP or BACnet MSTP protocol available for BAS integrations. Ensure that the meters have native Modbus TCP/IP or Modbus RTU protocols available for EPMS system integrations. Siemens SEM3 has both Modbus and BACnet protocol options available for different system integrations.

Q: How best do we do the metering and what devices are available to do this?

A: Siemens power meters and power quality meters meets the ANSI and IEC standards. Siemens has a variety of basic meters and advanced power quality meters for different applications. Please contact us at this link for further request on this topic.

Q: Please discuss submetering accuracy requirements and regulations.

A: In the U.S., revenue-grade submetering accuracy is ±1%. There are ANSI standards available to meet the accuracy. ANSI C12.20-2015: American National Standard for Electricity Meters established the physical aspects and performance criteria for a meter’s accuracy class. It supersedes certain details in ANSI C12.1-2014: American National Standard for Electric Meters – Code for Electricity Metering and ANSI C12.10-2011: American National Standard for Physical Aspects of Watthour Meters-Safety Standard.

The existing ANSI accuracy classes for electric meters are:

·         Class 0.5 – having ± 0.5% accuracy.

·         Class 0.2 – having ± 0.2% accuracy.

There are many regulation examples available:

·         NY PSC (New York Public Service Commission) certified meters: If the customer uses the submetering energy data to sub bill the tenants in the state of New York, then the meter must be certified by the New York Public Service Commission.

·         CA Weights & Measures Certified Meters (CDFA- California Department of Food and Agriculture – Division of Weights and Measures): If the customer uses the submetering energy data to sub bill the tenants in the Los Angeles county area, then the meter must be certified by CDFA.

·         Nationally recognized test lab (NRTL) certified meters: Most of the metering products in the industry goes through self-certification testing processes, which may be sufficient to get UL approval/certification. Many companies in the metering market take shortcuts. But only very few metering products in the industry go through very stringent testing processes to pass certain standards using the external NRTL.

·         Siemens SEM3 system meets all the above standards and passed through NRTL.

Q: Are embedded meters available for domestic (home) use at 120 V single-phase 20-amp supply?

A: Yes, the Siemens SEM3 system can measure 120 V single-phase circuits with a 20-amp supply. SEM3 measuring data is very accurate even when the load is very low, which is 1% of the amperage size.

Q: How does the SEM 3 system provide the corresponding potential sources for metering, especially when you might have mixed circuits such as 208Y/120 V and 480Y/277 V?

A: SEM3 can connect directly to a 480 V system and it is a single voltage and multiple current source system. Not used for mixed voltage inputs. If customers have mixed circuits, then they would have to purchase separate controllers for each voltage source.

Q: How does cost compare for embedded metering versus utility-type metering for a building with multiple tenants, say 20 tenants?

A: Costs probably are similar or lower than traditional metering in hardware. The biggest advantage is the customer can collect the data for analysis purposes over specific protocol, historical trending, alarm alerts, and additional savings is the electrical room size reduction. It can be reduced by 50%.

Q: Do all utilities accept this metering?

A: SEM3 is not a replacement for the utility meter. The SEM3 system is for submetering, but you could use it for monitoring incoming services as well. SEM3 can be used for tenant sub billing in conjunction with a third-party biller, where allowed by the utility.

Q: How does Siemens electrical metering solutions integrate with the Siemens BMS, Siemens flow meters, and Siemens Navigator dashboard?

A: Siemens electrical metering solutions can integrate with Siemens BMS using OPC interface. Also, Siemens BMS software has a built-in driver for some basic power meters and it could be easily integrated into the Navigator dashboard.

Q: What is maximum lead length on the current transformers (CTs) if remote mounting is necessary?

A: For SEM3 standard CT length is 6 ft, but the installer can extend the CTs up to 500 ft without losing accuracy or resolution.

Q: We need to spec open protocol. What do we need to put into a panelboard spec to ensure that power analysis software is compatible across several manufacturers?

A: In the electrical industry, Modbus TCP is very common protocol and most of the electrical power monitoring software systems would be compatible with that protocol.

Q: How does the cost of embedded metering compare with more traditional standalone third-party metering solutions (assuming both are for a new installation)?

A: SEM3 is very cost-effective solution compared to traditional standalone metering when the user wants to measure more circuits or loads. The more the circuits (up to 45 per controller) that the user wants to monitor, the higher the savings. The reduction in labor and startup costs often make embedded meters a better choice than “loose” meters.

Q: Seeing a panelboard with that many CTs, meter modules, the controller, and all the individual CT wires seems overwhelming. How many years will it be until we see the modules integrated into the CTs, which are addressable and daisy-chained with a single 2-wire serial cable?

A: The CTs are a standard design. They connect to a meter module that is a single part for all amperages (50 amps through 2,000 amps). This creates the most modular and scalable solution. One of the benefits of embedded metering is all the wiring is done at the factory prior to arriving to the site. Future additions are easy to incorporate in the field due to modular and easy to adapt systems.

Q: Do you recommend non-intrusive load monitoring devices? if not, why? If yes, for what scenarios do you recommend them and do you have such products?

A: We do not recommend non-intrusive load monitoring (NILM) because it is not 100% reliable in near real time. There are many privacy concerns for NILM. NILM can detect what types of appliances people have and their behavioral patterns. Patterns of energy use may indicate behavior patterns, such as routine times that nobody is at home, or embarrassing or illegal behavior of residents. It could, for example, reveal when the occupants of a house are using the shower, or when individual lights are turned on and off.

If the NILM is running remotely at a utility or by a third party, the homeowner may not know that their behavior is being monitored and recorded. NILM also still has many hurdles to overcome with regard to the wide variety of load profiles that have to be programmed for the metering to work. We see there are many more disadvantages than advantages.

Q: What services does Siemens provide on the subject of energy management?

A: The Siemens power distribution solutions engineering team provides the required experience and knowledge to implement any energy management system regardless of the size or complexity. Siemens solution engineers are highly skilled professionals who understand how to combine the best energy management software and hardware to create solutions that exceed our customers’ expectations.

Q: Are there temperature limitations (outdoor switchboards in cold winter locations and in summer sun)?

A: Switchboards and panelboards are rated to operate in ambient temperatures of 32 to 104°F. For lower temperatures, heaters can be installed in switchboards to regulate temperatures.

Q: In the past, some CTs could only detect down to a minimum current level. How does this affect accuracy and CT selection?

A: SEM3 CTs are calibrated to meet the SEM3 system accuracy. For example, if you have 50-amp CT and load can be as low as 0.5 amp for the SEM3 system to be very accurate. Basically, minimum load can be 1% of any CT amperage size up to 2,000 amps. SEM3 CTs meet the new UL 2808 standards, CAT IV for service entrance and pollution degree 3. Also, SEM3 CTs do not require a shorting block thanks to its built in self-shorting technology.

Q: Who are the business partners for energy data monitoring and revenue billing process?

A: We have couple of partners available depending on the regional location. Please contact us for more information.

Q: Will lighting and appliance panels become wider to provide for the code required gutter space.

A: Traditional P2 Panels are 20 in. wide. With the SEM3 system, we have increased the panel width to 24 in. to accommodate wire bending space according to the code. SEM3 components require 9 in. of unit space in bottom or top of the panel for monitoring up to 42 circuits.

Q: What is the commercial model to work with a building owner, especially for services?

A: Please contact us directly.

Q: Are the meters capable of displaying harmonic content of the waveform?

A: Not with SEM3 submeter, but we do have different meters with harmonic tools available to display the harmonic content.

Q: Does this product line come under Siemens Building Division? What solution and services do you provide for industry energy management?

A: The Siemens SEM3 embedded metering module product falls under the Siemens Energy Management Division, Low Voltage Products.

Q: Is the energy software sold separately or is it bundled with the hardware sale?

A: Siemens can sell either way. Typically, it is sold with the software for customer to take advantage of the full features and solution.

Q: What is the difference between using WinMP or Desigo CC?

A: WinPM.Net software is web enabled electrical power monitoring software (EPMS) and it can communicate to most all the power meters: Siemens power quality meters for power quality analysis and custom drivers for third party devices, such as UPS, PDU, RPPs, and generators. Desigo CC is building management software (BMS) specific to HVAC, fire security alarms, humidity, sensors, and basic metering. Desigo CC does not have power quality analysis. Both WinPM.Net software and Desigo CC software can be integrated seamlessly.

Q: Can we have your pricing catalog sent please?

A: For embedded metering, contact your local siemens authorized distributor who can provide quoting for the embedded options. Or send us the request online.