mvdc standards update - nsrp

MVDC Update

Dr. Norbert DoerryTechnical Directory, Technology Office

December 13, 2018VASCIC, Newport News VA

12/5/2018 Approved for Public Release Distribution is Unlimited 1

Setting the Scene“In FY2030, the DON plans to start building an affordable follow-on, multi-mission, mid-sized future surface combatant to replace the Flight IIA DDG 51s that will begin reaching their ESLs [Estimated Service Life] in FY2040.”

Report to Congress on the Annual Long-Range Plan for Construction of Naval Vessels for FY2015

Big differences from DDG 51:• High-energy weapons and

sensors• Flexibility for affordable

capability updates

Photo by CAPT Robert Lang, USN (Ret), from sitehttp://www.public.navy.mil/surfor/swmag/Pages/2014-SNA-Photo-Contest-Winners.aspx

12/5/2018 Approved for Public ReleaseDistribution is Unlimited 2

Power System Considerations

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“I’m going to buy as much as I can afford. As much power as I can afford. Because I know by the time I retire the ship I’ll use it all.”

Admiral John Richardson31st U.S. Chief of Naval OperationsDirected Energy Summit I March 29, 2017

Buy as much power as you can afford• Power (esp. with electric propulsion) is fundamental to ship

design and affects major components, arrangements, superstructure, compartmentalization, & ship control

The power system must include a better approach to distribution flexibility throughout the ship’s service life; current design practices optimize for current requirements

• DDG 1000 has plenty of installed power but a distribution system limited to current requirements• DDG 51 Flight III includes a costly power system upgrade for AMDR that was not in the original design

The Electric Power System is the Foundation of the Ship’s Kill Chain12/5/2018 Approved for Public Release

Distribution is Unlimited 3

Directed Energy Mission System Power Demands

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Key to Success = Energy Storage and Advanced Controls

• Pulses of a different nature require different ranges of pulse power technologies

• Future directed energy demands need common large scale energy storage

GENERATOR CHARGES ENERGY STORAGE

TIME

POW

ER

Energy Storage Response to LoadCurrent Future

• Generators operate at continuous loading for efficiency & reliability

• Current generators cannot respond quickly and dynamically to new demands

Generator Response to Load

TIME

POW

ER

Kinetic Weapons

Directed Energy Weapons and Sensors

ENERGY STORAGE PROVIDESPULSE POWER


Naval Power and Energy Systems Technology Development Roadmap

Aligned to the Navy’s 30 year shipbuilding plan and Surface Capability Evolution Plan (SCEP)

Serves as a guide for future investment by Navy, DoD, Industry, and Academia Includes all major product areas for Naval Power Systems

• Prime Movers• Generators• Energy Storage• Electric Motors• Distribution Systems• Power Converters• Controls

Originally issued in 2007 as part of the stand-up of the Electric Ships Office

Updated and re-issued in 2013 & 2015 2018 Version utilized CPES OIPT input

The Guidebook: NPES TDR

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2018 Version Currently in chop for SEA00 Signature12/5/2018 Approved for Public Release

Distribution is Unlimited 5

Why Medium Voltage DC?• Decouple prime mover speed from power quality

• Minimize energy storage• Power conversion can operate at high frequency – Improve power density• Potentially less aggregate power electronics

• Share rectification stages • Cable ampacity does not depend on power factor or skin effect• Power Electronics can control fault currents

• Use disconnects instead of circuit breakers• Acoustic Signature improvements• Easier and faster paralleling of generators

• May reduce energy storage requirements• Ability to use high speed power turbines on gas turbines


Affordably meet electrical power demands of future destroyer

Example MVDC Reference Architecture


MVDC Voltage Standards

• MVDC nominal voltages based on IEEE 1709• 6,000 VDC• 12,000 VDC • 18,000 VDC

• Current levels and Power Electronic Devices constrain voltage selection

• 4000 amps is practical limit for mechanical switches• Power electronic device voltages increasing with time (SiC will lead to great

increase)• For now, 12,000 VDC appears a good target …• Power Quality requirements under development


Existing MVDC Standards

• IEEE 1709-2018 Recommended Practice for 1 kV to 35 kV Medium-Voltage DC Power Systems on Ships


MVDC Technical Documents in the works• MIL-STD-1399 section on MVDC

• Complete mature draft exists• Industry reviewed multiple times• Submitted request to start Standards Project to TWH on 11/16/18

• MVDC Supplement to T9300-AF-PRO-020 rev 1 Electrical Systems Design Criteria and Practices (Surface Ships) for Preliminary and Contract Design

• Early complete draft exists• Industry reviewed early drafts• Incorporating comments and additional information

• MVDC Casualty Power System Specification• Subject of an SBIR

• MVDC Grounding Document• Subject of an STTR

• MVDC Fault Detection, Localization, and Isolation Document• Subject of an STTR


Discussion Topics for MIL-STD-1399 MVDC section• Measurement Methods

• Uses moving averages

• Verification Methods• Inrush current• Voltage Tolerance• Pulse Loads• Stability• Common Mode


Future MVDC Technical Documents

• Power Generation Module Specification• Draft Functional Requirements Documents exists

• Bus Node Specification • MVDC Disconnect Specification• MVDC Circuit Breaker Specification

• Cable / Bus Pipe Specification• Propulsion Motor Module Specification• PCM-1A / Energy Magazine Specification

• Specific Energy Magazine specifications exist• MVDC Control System Specification• DPC for Stability Analysis• Update of MIL-STD-2003 to address MVDC


Summary

• MVDC will come• Technology is maturing• Standards, Specifications, and

Guides are under development


Backup


Steady-State Measurements4.7 Steady-State Measurements. The steady-state DC component shall be calculated as the average value over a 100±1 ms moving time window. Steady-state ripple / non-DC component shall be calculated using the same time windows by subtracting the steady-state DC component from the waveform and calculating the root mean square value. The sampling rate shall be constant and sufficient to accurately measure the highest significant frequency component below 10 MHz. A frequency component is significant if it exceeds 5% of the largest frequency component. The time interval between the starts of time windows shall not exceed 20 ms.


𝑓𝑓𝑟𝑟𝑟𝑟𝑟𝑟2 (𝑡𝑡+) =1

𝑗𝑗𝑟𝑟𝑚𝑚𝑚𝑚 − 𝑗𝑗𝑟𝑟𝑚𝑚𝑚𝑚 + 1� 𝑓𝑓2

𝑗𝑗𝑟𝑟𝑚𝑚𝑚𝑚

𝑗𝑗=𝑗𝑗𝑟𝑟𝑚𝑚𝑚𝑚

(𝑗𝑗𝑡𝑡∆)

𝐹𝐹𝑑𝑑𝑑𝑑 (𝑡𝑡+) =1

𝑗𝑗𝑟𝑟𝑚𝑚𝑚𝑚 − 𝑗𝑗𝑟𝑟𝑚𝑚𝑚𝑚 + 1� 𝑓𝑓𝑗𝑗𝑟𝑟𝑚𝑚𝑚𝑚

𝑗𝑗=𝑗𝑗𝑟𝑟𝑚𝑚𝑚𝑚

(𝑗𝑗𝑡𝑡∆)

𝑓𝑓𝑟𝑟𝑚𝑚𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟 _𝑟𝑟𝑟𝑟𝑟𝑟 (𝑡𝑡+) = �𝑓𝑓𝑟𝑟𝑟𝑟𝑟𝑟2 (𝑡𝑡+)− 𝐹𝐹𝐷𝐷𝐷𝐷2 (𝑡𝑡+)

Ripple4.10 Ripple: Current ripple and current ripple frequency limits shall not be applicable during measurement time windows (see 4.7) that include inrush current, pulses, or when the negotiated values from control negotiations for current rate of change apply. Current ripple and current ripple frequency limits shall also not apply during equipment start-up and shutdown if the number of equipment start-ups and shut downs combined does not exceed 6 per hour on average. Voltage ripple limits shall not be applicable during measurement time windows that include voltage transients.


Load Change Measurement4.11 Load change measurement: A load change equals the larger of: a. minimum steady-state DC component in the first half of a 2 second time window minus the maximum steady-state DC component in the second half. Negative values are rounded up to 0.0. b. minimum steady-state DC component in the second half of a 2 second time window minus the maximum steady-state DC component in the first half. Negative values are rounded up to 0.0.


Current rate of change4.8 Current rate of change measurement: The current rate of change shall be calculated as the difference between the average value of the current measurements over the first half of a window and the average value of the current measurements over the second half of a window divided by half the time window duration. The window duration shall be no more than 10 ms and shall consist of a minimum of forty equally spaced current measurement samples. The time interval between the starts of successive time windows shall not exceed 20% of the time window duration.


5.2.3 Current Rate of Change: Unless otherwise specified in acquisition documentation (see 6.2) the load maximum current rate of change (no control negotiation) is 500 kA/second for load changes (see 4.11) of no greater than 20% of the load’s rated current. Unless otherwise specified in acquisition documentation (see 6.2) the load maximum current rate of change (no control negotiation) is 3.3 times the rated current per second for step load changes. A step load change is a load change of greater than 20% of the load’s rated current. The load maximum current rate of change (control negotiation) shall be in accordance with acquisition documentation (see 6.2). The control negotiations may include adjusting the time window value for calculating the Current Rate of Change. The load maximum current rate of change (no control negotiation) and the load maximum current rate of change (control negotiation) shall not apply to a particular load during the load’s start-up and shutdown if the number of start-ups and shut downs combined for that load does not exceed 6 per hour on average

Current Pulse Detection and Measurement4.9 Current pulse detection and measurement. For a pulse load, pulse detection and current pulse magnitude is based on the short-term average value calculated in an identical manner as for the half-window for the current rate of change measurement (see 4.8). A pulse is detected and its magnitude measured within a pulse window of 2 ±.001 seconds duration using the algorithms below. The time interval between the starts of successive pulse windows shall equal the time interval between the starts of successive short-term time window used for current rate of change measurements. a. Positive pulse detection. A positive pulse is detected in a pulse window if the maximum short-term average value exceeds both the minimum short-term average values before and after the maximum short-term average value by at least 25 amps. b. Negative pulse detection. A negative pulse is detected in a pulse window if the minimum short-term average value is exceeded by both the maximum short-term average values before and after the minimum short-term average value by at least 25 amps. c. Positive current pulse magnitude. If a positive pulse is detected within the pulse window, the positive current pulse magnitude is the larger of i. The difference between the maximum short-term average and the minimum short-term average values before the maximum short -term average. ii. The difference between the maximum short-term average and the minimum short-term average values after the maximum short-term average. d. Negative current pulse magnitude. If a negative pulse is detected within the pulse window, the negative current pulse magnitude is the larger of: i. The difference between the maximum short-term average before the minimum short-term average and the minimum short-term average. ii. The difference between the maximum short-term average after the minimum short-term average and the minimum short-term average.


Differentiate a pulse from a step load change

Pulse Loads and Step Load Changes

5.2.4 Pulse loads and step load changes. The load maximum current pulse (no control negotiation) shall be in accordance with acquisition documentation (see 6.2). Loads that do not exceed both the load maximum current pulse (no control negotiation) and the load maximum current rate of change (no control negotiation) are not required to communicate with the electric plant control system for the electrical power system prior to applying the pulse or load change to the interface. Loads that exceed either the load maximum current pulse (no control negotiations) or the load maximum current rate of change (no control negotiation) shall negotiate the maximum current pulse (up to the Load maximum current pulse (control negotiations),maximum current rate of change (up to the Load maximum current rate of change (control negotiations), and the start time of the pulse with the electric plant control system for the electrical power system. The protocols for conducting the negotiations shall be in accordance with acquisition documentation (see 6.2), or if not specified, in a manner approved by NAVSEA. The load maximum current pulse (control negotiation) shall be in accordance with acquisition documentation. (see 6.2)
