# Presentation: 143730

## CHP- Interconnection

- On-Site Power, CHP Interconnection
- Consultant Engineer/Owner Perspective
- April 22nd, 2004
- William Cristofaro P.E. - President
- Energy Concepts Engineering PC
- Ph: 585-272-4650
- www.nrg-concepts.com

- April 2004 FUPWG, Brooklyn, NY

## I-Connect – Engineer and Owner’s Goals

- Energy savings $
- First cost $
- System reliability
- Equipment safety – Owner + Utility
- Power Quality

- April 2004 FUPWG, Brooklyn, NY

## Slide 3

- April 2004 FUPWG, Brooklyn, NY

## Typical DG Plant Layout

- DG-1

- DG-2

- DG-3

- DG-4

**Building Heating**

**Domestic Hot Water**

**Air Conditioning**

**Other Processes**

**Electric Power**

**Heat**
**Recovery**
**Loop**

- Modular Cogen Assembly

- April 2004 FUPWG, Brooklyn, NY

## Interconnect – What is it ?

- DG-1

- DG-2

- DG-3

**Electric Power**

**Modular Cogen Assembly**

**Main Electric Power Panel**

**Power To Building**

**Electric Power From Utility**

**CB-52 Shunt**

- Trans.

**I-Connect Protection Relay**

**Power Quality Sensors**

**I-connect Controls**

**S**

**Utility**

**Cogen Power**

- April 2004 FUPWG, Brooklyn, NY

## Interconnect Function

- Protects Owner and Utility Equipment and personnel
- Opens CB-52 or similar shunt
- Isolates CHP plant from utility and building
- Shuts down Cogen units
- Must operate in less than 12 cycles (1/10 of a second)
- Latest technology about 6 cycles, about limit for mechanical operation.

- April 2004 FUPWG, Brooklyn, NY

## Interconnection Relay Panel

- Microprocessor based relay logic panel

- April 2004 FUPWG, Brooklyn, NY

## CB-52 Shunt Switch

- 6 cycle (1/10) sec operation.

- April 2004 FUPWG, Brooklyn, NY

## I-Connect, Types of Trips

- High/Low voltage per phase
- High/Low amps
- High/Low Frequency ( 60 cycles/sec)
- Reverse Power (Back to utility)
- Other more exotic functions
- Usually disturbances on utility system

- April 2004 FUPWG, Brooklyn, NY

## Causes of I-connect Trips

- Utility blackout – down for a while
- Utility brownout - visible but temporary
- Utility disturbance – not visible by human
- Cogen plant problem – usually only with synchronous type plants, unit trips first.
***Issue: Protective relay trips are more commonly the result of utility disturbances than on-site power plant problems.***

- April 2004 FUPWG, Brooklyn, NY

## I-Connect, Problems for Owner

- Brings on-site plant down
- Can create a demand spike and reduce kwh production
- Depending on technology, may take a while to bring plant back up: Fuel cells, steam turbine, photo-voltaic
- Creates various operational issues
- Issues can be addressed to quickly bring up CHP plant.

- April 2004 FUPWG, Brooklyn, NY

## Addressing I-Connect Owner Issues

- Wider settings for trip set points, ie allow variances within owner’s tolerance. **
- Good quality interconnect equipment
- Automatic on-site plant restart **
- Annunciation, alarms and calling
- Procedure design and education

******** Issues of concern/discussion with utility**

- April 2004 FUPWG, Brooklyn, NY

## Automatic Re-closure

- Purpose to avoid utility demand spike during brownout or disturbance.
- When power quality “good” for 2 minutes automatically re-closes CB-52
- Special computer program sequence for rapid plant restart
- The “15 minute race” for demand savings or charges.

- April 2004 FUPWG, Brooklyn, NY

## Interconnect – What is it ?

- DG-1

- DG-2

- DG-3

**Electric Power**

**Modular Cogen Assembly**

**Main Electric Power Panel**

**Power To Building**

**Electric Power From Utility**

**CB-52 Shunt**

- Trans.

**I-Connect Protection Relay**

**Power Quality Sensors**

**I-connect Controls**

**S**

**Utility**

**Cogen Power**

- April 2004 FUPWG, Brooklyn, NY

## Proper Trip Set Points

- Purpose to provide protection yet avoid nuisance and “false” trips
- Power quality survey needed, what is real baseline background for power quality.
- Programmable set points and functions provides flexibility per site needs.
- Ability to work with utility relay personnel to build confidence and negotiation.
- Different for Induction vs Synchronous

- April 2004 FUPWG, Brooklyn, NY

## I-Connect, Technology Advances

- Technology working in favor of both utilities and owners.
- Reliability increasing
- Cost decreasing
- Interconnection often not a problem for the experienced, but often more than expected by many.

- April 2004 FUPWG, Brooklyn, NY

## Technical Issues for Action

- Further refinement of NYS interconnection standard.
- Con Edison – address synchronous plants in parallel with network system.
- Interconnection for “small” plants
- VS Interconnection for “large” plants.
***Proper technology and standards can benefit both utilities and owners.***

- April 2004 FUPWG, Brooklyn, NY

## I-Connect, Administrative Issues

- Utility response time
- Consistent review team with utility (good example – NYSEG + RG&E specific group.)
- Consistent standards
- Methods of review and comment – best to make it more interactive.
- Legal interconnection contract issues

- April 2004 FUPWG, Brooklyn, NY

## I-Connect, Owner Goals

- Technical reliability can be met with proper engineering and equipment.
- Energy savings can be enhanced with automatic equipment (restart)
- Cost can be controlled with proper utility-engineer interface and good equipment.
- More work needed via tech standards
- More work needed via administrative and legal process.

- April 2004 FUPWG, Brooklyn, NY

## I-Connect - Standards

- For standards to be truly useful they must be practical.

- April 2004 FUPWG, Brooklyn, NY