Power Network Control by HDC in Japan The 8 th EPCC Workshop June 2005 Toshiba Corporation Tokyo Japan Courtesy of N. Fukushima 1
Power Network Control by HDC in Japan Islands are connected by HDC. The 50Hz system and the 60Hz system are connected by HDC as frequency converter. Specially designed controls are utilized in addition to normal power control on HDC. 2
HDC Projects in Japan AFC : Automatic Frequency Control FC : Frequency Converter EPPS : Emergency Power Pre-Set PM : Power Modulation Minami - Fukumitsu BTB 300MW 1999 (AFC) Hokkaido-Honshu HDC Link 600MW 1993 (AFC) Shin-Shinano FC 600MW - 1992 Higashi-Shimizu FC 300MW - 2006 (EPPS) Sakuma FC 300MW - 1965 Kii Channel HDC Link 1400MW 2000 (PM, Fast power recovery, AFC) 3
Inter-Regional Interconnection in Japan (as of 2004) 60Hz (101GW) Kyush u 17GW 500k Chugok u 12GW 500k Shikok u 5.9GW 500k KII Channel HDC Link Hokurik u 5.5GW 500k Kansai 33GW MINAMI- FUKUMITSU BTB 500k 500k Chubu 28GW 275k Hokkaido- Honsyu HDC Link SHIN- SHINANO FC 500k FC 275k 275k SAKUMA Tohok u 15GW Hokkaid o 5.3GW 500k Tokyo 64GW Hakodat e 250k Kamikita 50Hz (84GW) 4
EPPS EPPS is for emergency cases where one of the two frequencies (50 or 60 Hz) exceeds some limits. In such an emergency case EPPS immediately sends the pre-set power to the abnormal frequency power system to recover the frequency. EPPS has long been successfully operated with many actual operations in Japan. 5
Multi-variable AFC Control Frequency of Network A (Hokkaido-Honsyu HDC) Frequency of network B Hokkaido island Network A f-reference Network B f-reference Integral control Feed@Back Control Bipole Control ƒ PA ƒ PB Observer DC Power reference Honshu island Network A Network B 6
Effects of AFC (Hokkaido-Honsyu HDC) Ordinary AFC Hokkaido f 1min Emergency AFC Hokkaido f Pole-1 DC Current Honshu f DC Power Order Honshu f DC Power Order Pole-2 DC current Emergency AFC switching on AFC switching on 7
Minami-Fukumitsu BTB C/S KEPCO HEPCO CEPCO Minami-Fukumitsu BTB Minami-Fukumitu BTB can prevent unnecessary loop flows among the 3 utilities, and can control the power flow between HEPCO and CEPCO freely. HEPCO: Hokkuriku Electric Power Co. KEPCO: Kansai Electric Power Co., CEPCO: Chubu Electric Power Co. 8
Actual Power System Test Tie Line was opened. KEPCO HEPCO CEPCO A Pumping-up generator was tripped in Pump Mode with 120MW. G BTB was operated in AFC Mode. When tie line between KEPCO and HEPCO is opened, BTB is operated in AFC mode. 9
Actual Power System Test frequencyi g šj DC currentipu 60.10 60.05 60.00 59.95 59.90 1.00 0.90 0.80 0.70 0.60 0.50 0.40 +0.05Hz 0.0 5.0 10.0 15.0 timeisec) 105MW 0.0 5.0 10.0 15.0 tim eisec) Pump rejected magenta: HEPCO blue : CEPCO By increasing the DC power from HEPCO to CEPCO by 105 MW, the maximum frequency changes are suppressed to less than 0.04 Hz. 10
Kii Channel HDC Link AC 500k line HDC 1400MW, ±250k, Tachibana -Wan p/s Submarine Cable: 50 km Overhead Line 50 km Anan c/s Yura s/s Kihoku c/s Note: P/S=Power Station, S/S=Switching Station, C/S=Converter Station 11
Power Modulation study 12
Record of Power Modulation HDC 1400MW (from Sikoku to Kansai) Power of AC line and HDC Chuugoku Line O (500k) 2600 2200 Kyushu Sikoku Power unbalance Kansai HDC power setting Chubu Power [M W] 1800 1400 1000 600 M start ( & Timer) opposit e polality Pac on Line-O PD on HDC M stop ( & Timer) -2 0 2 4 6 8 10 12 Time [sec] Power swing is well suppressed by PM controller 13
Power flow at 1-phase 1 fault Awa G Anan Records of Fast Power Recovery after AC fault 9331177 1177MW -pole d -pole Tachibana Gen d Id Id Kihoku ac Sinikoma C-phase 1phaseG-O Recorded chart AC oltage (ac) DC oltage (d) A B C 247k -pole -pole -247k 50ms 3cycles 100ms 0.9p u Pdc was recovered within 100ms after fault clearing Lightning attacked 11times during 2 months after commission, fast power recovery was completed successfully for all cases 14
Japan Electric Power Exchange (JEPX; Started from April 2005) JEPX is private and voluntary It accepts only physical transactions Wholesale power exchanges are treated It is the single market for the whole Japan as long as all the ATCs are not violated ATCs are checked to facilitate each power exchange between players It is to supplement bilateral transactions 15
ATC of Each Inter-Tie Line ATC = TTC Margin Scheduled Flow ATC; Available Transfer Capability Margin; Reserved for some risks TTC; The most severe constraint among thermal, stability, voltage stability, and frequency limit. It is equipment limits for HDC, BTB, FC links. Scheduled Flow; Reserved for bilateral contracts for long time 16