Report_Proposed_Generator_Excitation_Modifications.pdf

FRV SHIMADA

PROPOSED

GENERATOR EXCITATION MODIFICATIONS

GENERATOR KW LOAD SHARE MODIFICATIONS

PRINT PACKAGE FOR SUBMITTAL TO ABS

Client: NOAA Newport, Oregon

Submission to NOAA date: 30 November 2017

Engineer: W. N. Clewes

`141 Riverview drive

Littleton, NH 03561

603 444 2949, 603 303 6442 clewtec@roadrunner.com

Company: C & T Marine

1 Beechwood Court

Portsmouth, Va. 23702

757 285 4598 mailto:clewtec@roadrunner.com

Proposed modifications / change discussion

1: Generator droop current transformer change.

The originally installed current transformers have been found to be operating in the core saturated area of the output curve. This results in highly inaccurate reactive droop signals for the voltage regulators to utilize in calculating an appropriate correction to allow proper KVAR sharing with other generators.

Change is to replace the original current transformer with a similar X / Y dimension unit of the same ratio but with a much higher burden capacity, relay class rated.

This action was accomplished on the two original FRV vessels with very good results.

2: Addition of a zero center VAR meter to the generator metering package.

The existing switchboard metering does not allow for easy determination of reactive load share between generators. The installation of a zero center VAR meter will greatly improve this situation.

To be able to install a zero center VAR meter at the switchboard it will be necessary to replace the existing generator voltmeter and frequency meter with a dual display single digital meter.

When this is accomplished panel space becomes available for the VAR meter installation.

3: Reverse power relay modification

During the research in to the reactive and real load sharing issues on Shimada it was discovered that that a print error existed. The print shows the reverse power relay current transformer connection as using phase 2 current transformer. This is incorrect for the Basler ES 32 style of reverse power relay. This relay requires phase 1 current transformer be utilized. All four (4) generators are correctly installed as phase 1 current is actually utilized. This action is simply a print correction to show as built.

4: Generator over voltage protection.

The original overvoltage protection as shown on the KATO generator excitation print contains two serious deficiencies.

First is the over voltage protection sensing is the feedback voltage to the generator voltage regulator. If this voltage signal should happen to be removed the generator voltage would go to a very high and dangerous level. The over voltage protection system would not know of the high voltage thus no protection is offered to the ships electrical power system.

Second issue is that if the overvoltage trip device should operate and shut down the generator excitation the generator is allowed to remain connected to the bus. Thus will cause a lot of undue reactive load transfer between generators with subsequent voltage disturbances that are not necessary nor desired.

The proposed overvoltage protection circuit looks at a voltage not utilized by the voltage regulator for feedback. If the overvoltage protection system should trip an operation flag is displayed at the 86G device, the PMG power to the voltage regulator is removed causing the regulator output to go to zero and a trip command is given to the generator circuit breaker.

The voltage being monitored is the 120 Volt AC control power taken from a CPT on the generator side of the circuit breaker. If the 120 Volt AC control is removed the overvoltage protection system is not allowed to operate, however the generator circuit breaker will be cased to trip offline by action of the circuit breaker under voltage device. This isolates the high voltage to the one generator and it is off line.

5: Speed Trim potentiometer operation by the automation power system management

Speed control of the generator is the sole responsibility of the engine governors with no outside influence from some other system. The proposed action will disable the remote action of the speed trim pot by removing relays SSR and SLR along with all associated wiring.

This action was taken on Dyson and Bigelow and has proven to be the correct action. A portion of the real (KW) load share issues were traced back to the automation on the two original FRV vessels.

6: Real (KW) load share lines and switching improvements.

The existing KW load share lines are passed thru the auxiliary contacts of the three bus tie circuit breakers. These contacts are not well suited to low level micro / milliamp signals.

Based on work done Dyson / Bigelow we propose removing the actual switching of the governor load share lines from the circuit breakers and have the circuit breaker pilot a control relay. The control relays being considered are low level signal relays with bifurcated contacts suited for the application. This change made to Dyson / Bigelow made a significant improvement in KW load share.

7: Automatic generator control module installation

Proposed action is installation of a Woodward automatic generator load control (AGLC) module. The function of this module is to soft load and unload a generator when a trip command is given.

Presently the generator as taken to load share as soon as the breaker is closed or all load is instantly removed when a trip command is given.

With an AGLC module installed when a generator is commanded to go on line the circuit breaker closes as normal however the load is caused to be ramped up over a few seconds to the new machine on line. The ramp time is adjustable to fit the needs. This is a much better arrangement for the engines as it greatly reduces the stress of the engine.

When a generator is commanded to trip off line the AGLC panel causes the generator KW load to decay on a ramp, locally adjustable to system needs, until approximately 10% of rated load remains on the generator. At this point a trip command is issued to the circuit breaker.

Thus action was taken on Dyson and Bigelow with very good results.

8: Removal of voltage sensing filter at Kato generator excitation panel.

The sensing filter assembly (SF) contains shunt capacitors and series resistors arranged in a network arrangement. This filter causes a small but measurable phase shift of the sensed voltage. This phase shift makes it very difficult to obtain a fine and exact reactive load share.

The Basler SSR 125 family of voltage regulators has been used in several hundreds of applications without SF filter assemble present with proper results and normal life expectancy.

The author has experienced this SF assembly in other locations both marine sea going and shore side industrial applications. In each case where the SF filter was removed reactive load share improved.

ATTACHMENTS:

1: Shallco type 26 Lockout Relay data sheets

2: Basler type ES 59 voltage sensing relay data sheets

3: Basler type ES 32 reverse power relay data sheets

4: Woodward AGLC product manual #82004

5: Crompton switchboard meter catalog sheet, AC Varmeter

GENERATOR # 1 MODIFICATIONS

Print # 05S025-10101A

Date: Engineer Change description

11/24/17 W. N. Clewes Corrected Rev Pwr. relay to reflect actual install

11/24/17 W. N. Clewes Changed VM and FM to a single dual display instrument

11/24/17 W. N. Clewes Added zero center KVAR meter

11/24/17 W. N. Clewes Changed droop current transformer to unit with higher burden capacity, ratio remains same as original

Print # 05S025-10101B

Date: Engineer Change description

11/24/17 W. N. Clewes No changes to this sheet

Print # 05S025-10101C

11/24/17 W. N. Clewes Added 86G trip to generator circuit breaker control

11/24/17 W. N. Clewes Added Generator over voltage trip circuit

11/27/17 W. N. Clewes Remove 1PM1 contact from 52G trip circuit

11/27/17 W. N. Clewes Add AGLC X relay contact to 52G trip circuit

11/27/17 W. N. Clewes 52G 1 aux contact A23 / 24 to AGLC logic input

Print # 05S025-10101D

Date: Engineer Change description

11/24/17 W. N. Clewes Removed relay SRR and associated wiring

11/24/17 W. N. Clewes Removed relay SLR and associated wiring

11/24/17 W. N. Clewes Removed bus tie breaker contacts in KW load share circuits

11/24/17 W. N. Clewes Add AGLC panel to KW load share lines and 52G trip logic

GENERATOR # 2 MODIFICATIONS

Print # 05S025-20101A

11/24/17 W. N. Clewes Corrected Rev Pwr. relay to reflect actual install

11/24/17 W. N. Clewes Changed VM and FM to a single dual display instrument

11/24/17 W. N. Clewes Added zero center KVAR meter

11/24/17 W. N. Clewes Changed droop current transformer to unit with higher burden capacity, ratio remains same as original

Print # 05S025-20101B

Print # 05S025-20101C

11/24/17 W. N. Clewes Added 86G trip to generator circuit breaker control

11/24/17 W. N. Clewes Added Generator over voltage trip circuit

11/27/17 W. N. Clewes Remove 2PM1 contact from 52G trip circuit

11/27/17 W. N. Clewes Add AGLC X relay contact to 52G trip circuit

11/27/17 W. N. Clewes 52G 2 aux contact A23 / 24 to AGLC logic input

Print # 05S025-20101D

11/24/17 W. N. Clewes Removed relay SRR and associated wiring

11/24/17 W. N. Clewes Removed relay SLR and associated wiring

GENERATOR # 3 MODIFICATIONS

Print # 05S025-30101A

11/24/17 W. N. Clewes Corrected Rev Pwr. relay to reflect actual install

11/24/17 W. N. Clewes Changed VM and FM to a single dual display instrument

11/24/17 W. N. Clewes Added zero center KVAR meter

11/24/17 W. N. Clewes Changed droop current transformer to unit with higher burden capacity, ratio remains same as original

Print # 05S025-30101B

Print # 05S025-30101C

11/24/17 W. N. Clewes Added 86G trip to generator circuit breaker control

11/24/17 W. N. Clewes Added Generator over voltage trip circuit

11/27/17 W. N. Clewes Remove 3PM1 contact from 52G trip circuit

11/27/17 W. N. Clewes 52G 3 aux contact A23 / 24 to AGLC logic input

Print # 05S025-30101D

11/24/17 W. N. Clewes Removed relay SRR and associated wiring

11/24/17 W. N. Clewes Removed relay SLR and associated wiring

GENERATOR # 4 MODIFICATIONS

Print # 05S025-40101A

11/24/17 W. N. Clewes Corrected Rev Pwr. relay to reflect actual install

11/24/17 W. N. Clewes Changed VM and FM to a single dual display instrument

11/24/17 W. N. Clewes Added zero center KVAR meter

11/24/17 W. N. Clewes Changed droop current transformer to unit with higher burden capacity, ratio remains same as original

Print # 05S025-40101B

Print # 05S025-40101C

11/24/17 W. N. Clewes Added 86G trip to generator circuit breaker control

11/24/17 W. N. Clewes Added Generator over voltage trip circuit

11/27/17 W. N. Clewes Remove 3PM1 contact from 52G trip circuit

11/27/17 W. N. Clewes 52G 4 aux contact A23 / 24 to AGLC logic input

Print # 05S025-40101D

11/24/17 W. N. Clewes Removed relay SRR and associated wiring

11/24/17 W. N. Clewes Removed relay SLR and associated wiring

BUS TIE CIRCUIT MODIFICATIONS

Print # 05S025-11013B

11/24/17 W. N. Clewes Add relay BTA/LS

Print # 05S025-11015B

Date: Engineer Change description

11/24/17 W. N. Clewes Add relay BTB/LS

Print # 05S025-11017B

11/24/17 W. N. Clewes Add relay BTC/LS

New Sheet: un-numbered, from Dyson / Bigelow rehabilitation project

KW Load Share Lines Arrangement

Date: Engineer Description

11/24/17 W. N. Clewes New KW load share lines and AGLC panel addition details

Print dated: 0/02/2008

KATO ENGINEERING PRINT MODIFICTIONS

Print # 888-00178-25 910 KW generator

11/24/17 W. N. Clewes Remove SF filter assembly

Remove MOP reference from print

Remove existing over voltage protection circuit

Add 86/G contact to PMG input to volt regulator

Print # 888-00178-24 1380 KW generator

11/24/17 W. N. Clewes Remove SF filter assembly

Remove MOP reference from print

Remove existing over voltage protection circuit

Add 86/G contact to PMG input to volt regulator